Singletons, state, import, and typer.Context
Date: 2025 11-November 01
typer.Context is Context a singleton class? What does it carry on import? If imported into another file, does it carry state?
Excellent question β this dives into a subtle but important aspect of how Typer (and by extension, Click) works internally.
Letβs break it down cleanly:
π§© What is typer.Context?
typer.Context is a runtime object created by Click (Typerβs underlying library) when a CLI command is invoked.
It is not a singleton, and it is not persistent across imports or invocations.
Each time a command is executed via Typer (e.g., when you run python -m pipeline.cli help), a new Context instance is created and passed into the command or callback function.
π§ When and where Context exists
The Context object only exists:
-
During command execution, as part of Typer/Clickβs internal command tree resolution.
-
As a parameter to your callback or command function (like
def main(ctx: typer.Context)). -
It is automatically constructed and destroyed by Typer for that single CLI invocation.
You cannot normally create one yourself and expect it to behave meaningfully without Click/Typer orchestrating it.
βοΈ Import behavior
If you import typer.Context from another file:
from typer import Context
you are importing the class definition, not an instance.
So this carries no runtime state β no context variables, no command info, nothing.
Itβs equivalent to importing any other class:
from datetime import datetime
The class is imported, but no object exists until you instantiate it.
π§± Why c.help() fails in your __main__.py
When you do this:
import pipeline.cli as c
c.help()
youβre calling the Typer command function as a plain Python function, not via Typerβs CLI engine.
That means:
-
Typer never constructs a
Context -
The
ctxargument isnβt provided -
So you get a
TypeError(missing required positional argumentctx).
β Correct ways to invoke the command
Option 1 β Let Typer handle it
Run it as a CLI command:
python -m pipeline.cli help
This ensures Typer creates a Context and passes it to your command.
Option 2 β Simulate invocation programmatically
You can run it programmatically with Typerβs testing utilities or Click internals:
from typer.testing import CliRunner
from pipeline.cli import app
runner = CliRunner()
result = runner.invoke(app, ["help"])
print(result.output)
This constructs a real Typer context and runs your command properly.
β οΈ Do not rely on Context as shared state
Because Context is ephemeral, you cannot rely on it to carry persistent or global state between commands or modules.
If you need shared CLI-level configuration (e.g., loaded credentials, environment paths, or flags), do one of the following:
-
Use a singleton-style configuration object (e.g.,
PipelineConfig.current) -
Use Typerβs
Context.objattribute to store a dict or custom object during the invocation:@app.callback() def main(ctx: typer.Context): ctx.obj = {"db_path": "path/to/db.sqlite"} @app.command() def do_something(ctx: typer.Context): typer.echo(ctx.obj["db_path"])
β¦but even then, that state only exists within the same CLI process.
π§ Summary
| Property | Description |
|---|---|
| Type | typer.Context (a subclass of click.Context) |
| Singleton? | β No β a new instance per CLI invocation |
| Persistent across imports? | β No β recreated each time Typer runs a command |
| Carries state on import? | β No β only carries state at runtime during command execution |
| Where to use it | Inside command or callback functions |
| How to test programmatically | Use typer.testing.CliRunner.invoke() |
If youβd like, I can show how to adapt your __main__.py to invoke pipeline.cli.app directly (so you can run commands programmatically and still have a valid Context). Would you like me to show that version?
Is there any correct way to carry persistent or global across imports, or is this an antipattern as a whole, and any approach would be misled? Checking temporary files would be more explicit and without side effects; though i could learn more about how import works in order to understand the implications of Singleton import
Thatβs an exceptionally good and nuanced question β youβre thinking about this at exactly the right depth.
Letβs unpack it carefully, because this touches Python import semantics, Typer/Click lifecycle, and good architectural hygiene.
βοΈ 1. The import system and persistence
When you import a Python module, the interpreter:
-
Loads and executes the module once (creating a
moduleobject). -
Caches it in
sys.modulesunder its import path. -
Any subsequent imports just reuse that same object reference.
So within a single Python process, imports are singleton-like by default:
# file_a.py
state = {}
# file_b.py
import file_a
file_a.state['foo'] = 123
# file_c.py
import file_a
print(file_a.state) # {'foo': 123}
That shared in-memory state persists only within the same interpreter session (e.g. while your CLI command is running).
Once the process exits, itβs gone.
So technically yes β you can persist runtime state across imports by storing data in a module-level variable.
π§ 2. Why this feels like a βSingletonβ pattern
That behavior effectively gives you a natural singleton, since:
-
importreturns the same module object each time, -
And its top-level variables are shared.
But that is not a true singleton class, because you canβt enforce instantiation rules β itβs just a module with persistent process-local state.
β οΈ 3. Why this is usually an anti-pattern in CLI contexts
In the context of Typer, Click, or other command-driven frameworks, relying on module-level globals for βshared stateβ tends to backfire for a few reasons:
π CLI calls are separate processes
Each CLI command invocation (python -m pipeline.cli ...) runs in a fresh process.
That means your βglobalβ module state is gone after each run.
So any "persisted" state doesnβt persist across invocations β only within that run.
𧨠Global mutation is non-obvious
If another file modifies a shared global, itβs invisible and implicit:
helpers.config['debug'] = True
That can cause side effects across imports, making testing and reasoning harder.
π§© Click/Typer expects purity
The framework encourages commands to be pure functions of input arguments and options.
Hidden dependencies or mutable globals break that mental model and make help, autocompletion, and testing less predictable.
πͺΆ 4. When a βglobal-ishβ approach is legitimate
There are acceptable, explicit versions of global persistence, as long as you make the boundaries clear:
β a. A dedicated configuration or workspace manager
Example:
# pipeline/config_manager.py
class ConfigManager:
_instance = None
settings = {}
@classmethod
def get(cls):
if cls._instance is None:
cls._instance = cls()
return cls._instance
config = ConfigManager.get()
Then anywhere:
from pipeline.config_manager import config
config.settings['plant'] = "Maxson"
This is okay because:
-
Itβs explicit (
configis the access point), -
You control initialization,
-
You can reset or serialize it safely.
In your case, your existing ProjectManager or WorkspaceManager could fill this role.
β b. Persistent configuration via files
Your instinct here is spot on:
βChecking temporary files would be more explicit and without side effects.β
Using local JSON/TOML/SQLite state is far safer and more explicit:
-
No runtime ambiguity.
-
Works across sessions and processes.
-
Easier to debug and recover from corruption.
This is also a natural extension of what you already do in your security/config subsystem β using persisted credentials, default projects, etc.
β c. Context-based persistence (scoped lifetime)
Typer allows attaching an object to the Context:
@app.callback()
def main(ctx: typer.Context):
ctx.obj = {"project": "eds_to_rjn"}
Thatβs a clean way to share ephemeral state between subcommands within a single run, but it wonβt persist beyond process exit.
π§± 5. Import persistence: a mental model
You can think of modules like this:
| Persistence Layer | Lifetime | Scope | Best Use |
|---|---|---|---|
| Local variable | per function call | single scope | transient data |
| Class attribute | per process | class scope | shared config among instances |
| Module-level variable | per process | module scope | light global cache |
| File-based state | across runs | persistent | config, cache, history |
Using a file (even a lightweight JSON in %APPDATA%) gives you deterministic persistence without weird import semantics.
πͺ 6. Summary β guiding principles
| Approach | Scope | Recommended? | Notes |
|---|---|---|---|
typer.Context |
per CLI invocation | β ephemeral only | good for in-process shared data |
| Module globals | per process | β οΈ okay if contained | not across commands |
| Singleton class | per process | β if explicit | for config or workspace state |
| Temp/JSON/TOML files | cross-process | β β | explicit, reproducible |
| Hidden mutable imports | per process | β | implicit side effects |
π§© Practical recommendation for your CLI (Pipeline)
Given your architecture (daemon, workspaces, CLI commands, user configs), the ideal hybrid is:
-
Use a singleton manager (
WorkspaceManager,SecurityManager, etc.) for in-memory state. -
Mirror that state to explicit JSON/TOML config files so it persists safely across CLI runs.
-
Avoid using module globals unless theyβre immutable constants.
Would you like me to show you a clean pattern for a singleton config manager that keeps in-memory state and syncs to disk automatically (i.e., βexplicit persistence but implicit convenienceβ)?
Clayton 3:
Module-level variable
per process
module scope
light global cache
this sounds dangerous
Youβre absolutely right β and your instinct to be skeptical here is exactly the right one.
Letβs unpack why module-level state is both tempting and subtly dangerous, especially in the context of a CLI or long-lived service.
βοΈ What a module-level variable really is
When you write:
# config.py
settings = {"debug": False}
then later:
import config
config.settings["debug"] = True
that value mutates the single shared config module object stored in sys.modules.
Any other part of your program that imports config sees the same settings dict.
So yes β it behaves like a βglobal cache.β
β οΈ Why itβs dangerous
1. Implicit shared state
Every file that imports that module is implicitly coupled to it.
helpers.state['active_project'] = 'foo'
This means another part of your program could change it without you realizing, breaking invariants in subtle ways.
Itβs easy to forget where a value was set, and difficult to reset or test safely.
2. Order-of-import problems
If your module runs code on import (e.g., initializes a DB connection),
the timing and order of imports suddenly matter β a huge source of bugs in larger systems.
Example:
# db.py
conn = sqlite3.connect(DB_PATH) # runs at import
If DB_PATH isnβt configured yet when db imports, youβre in trouble.
3. Incompatibility with concurrency
Threads, subprocesses, or async tasks that all share the same module may:
-
Mutate the same dict at the same time (race conditions),
-
Or end up with inconsistent state when each process re-imports independently.
4. Breaks composability
Libraries or submodules that rely on hidden globals canβt easily be reused elsewhere or tested in isolation β you canβt just import them without dragging in that global behavior.
5. Typer/Click lifecycle mismatch
In Typer/Click CLIs, each command run is a new process, so module-level state doesnβt persist anyway.
But inside a daemon, the same process may run multiple commands β and thatβs where stale globals can leak across runs.
β When it can be acceptable
Module-level data is not evil, itβs just easy to misuse.
Itβs fine for:
-
Immutable constants
DEFAULT_TIMEOUT = 5 -
Read-only caches (e.g., computed once, never mutated)
_timezone_cache = zoneinfo.ZoneInfo("America/Chicago") -
Tiny, bounded caches with clear ownership
(e.g., memoized results of deterministic functions)
But once you start mutating them, youβre creating hidden state.
π§ Safer alternatives
1. Explicit singletons or managers
Define an explicit object that owns state and can be passed, reset, or serialized:
class ConfigManager:
def __init__(self):
self.debug = False
self.project = None
config = ConfigManager()
This is still βglobalish,β but itβs explicit and testable.
2. File-based persistence
Persist configuration or session data to a JSON/TOML/SQLite file.
Thatβs deterministic and side-effect free across runs.
3. Context objects
For ephemeral command-scope data, use typer.Context.obj or a local object you pass between functions.
π§© Summary
| Technique | Scope | Mutability | Safe? | Notes |
|---|---|---|---|---|
| Module-level constants | Global | β | β | Use for fixed values |
| Module-level mutable dict | Global | β | β οΈ | Hidden state; avoid |
| Singleton manager | Global | β | β | Explicit control |
| File/DB persistence | Cross-process | β | β β | Clear, explicit |
| Typer Context | Per-invocation | β | β | Safe for ephemeral state |
πͺΆ Bottom line
Module-level mutable state is a footgun.
Itβs okay for caches or constants, but never as a communication mechanism between modules.
If you need βsomething to remember,β make it explicit (config manager, context, or persisted file).
That gives you predictability and makes debugging sane.
Would you like me to show a short code example comparing a βdangerous globalβ versus a βsafe singleton managerβ for the same task (so you can see the difference in practice)?
Is it fair to say that the only safe way to import state is file based OR it could very easily be made file based?
β Yes β thatβs an extremely fair and well-grounded statement.
Letβs refine it slightly for precision, because itβs actually a principle-level truth in Python application design:
The only safe and predictable way to import persistent state is via a file (or other external persistence layer).
Everything else β module variables, singletons, imported globals β is ephemeral and process-bound. It might feel persistent during one run, but itβs not durable, reproducible, or isolated.
π Why βfile-basedβ is the safe boundary
Files (or databases, or any persistent storage) introduce an explicit serialization boundary between:
-
βCode that defines behavior,β and
-
βData that represents state.β
That boundary gives you:
-
Determinism β reloading the file gives the same state every time.
-
Transparency β you can inspect and audit it.
-
Isolation β two processes donβt stomp on each otherβs memory.
-
Recoverability β if corrupted, you can delete or repair it.
-
Portability β other tools can read/write the same data.
Compare that to hidden module-level variables:
-
Invisible from outside,
-
Implicitly mutable,
-
Non-persistent,
-
Easily stale between imports.
π§ The βcould easily be made file-basedβ idea
Yes β thatβs also completely valid and pragmatic.
If a module or CLI needs to βrememberβ something, you can almost always replace in-memory globals with lightweight file-backed state.
Examples:
Before β unsafe module cache
# pipeline/state.py
active_project = None
After β explicit file-backed persistence
# pipeline/state.py
from pathlib import Path
import json
STATE_FILE = Path.home() / ".pipeline_state.json"
def get_state():
if STATE_FILE.exists():
return json.loads(STATE_FILE.read_text())
return {}
def set_state(key, value):
data = get_state()
data[key] = value
STATE_FILE.write_text(json.dumps(data))
Now, your CLI can do:
import pipeline.state as state
state.set_state("active_project", "eds_to_rjn")
print(state.get_state()["active_project"])
This will work across imports, across sessions, and even across machines β all with zero hidden side effects.
π§± The mental model hierarchy
| Persistence type | Where it lives | Survives process restart | Safe to import? | Typical use |
|---|---|---|---|---|
| Local variable | Stack frame | β | β | ephemeral computation |
| Class instance | Heap | β | β (explicit) | managed runtime state |
| Module global | sys.modules | β | β οΈ risky | config constants, caches |
| Singleton pattern | Heap | β | β (explicit) | runtime config holder |
| File / DB | Disk / external | β | β β | durable config/state |
The key dividing line:
Everything above the file boundary is transient and shared.
Everything below it (file, database, socket, API) is explicit and persistent.
π§ Practical takeaway
If you ever find yourself writing or reading:
some_module.current_project = "X"
β¦ask yourself:
βCould this just be stored in a config file instead?β
In almost every case, yes β and that will:
-
Simplify debugging,
-
Avoid mysterious state leaks,
-
Make your CLI behavior reproducible,
-
And play nicely with Typer/Click, daemons, or subprocesses.
So your statement could be refined into a maxim:
βAll state that must survive import boundaries should live in files.
Everything else is transient, and should be treated as disposable.β
Thatβs a solid rule of thumb for Python CLI, daemon, or service architecture β and youβre absolutely right to anchor your design around it.
Clayton 4
I am interested in the lightweight file based approach.
I am interested in ascii encoded or plaintext databasing, or at least very easy to discover and explore; aside from secure credentials which I manage with the python keyring / cypher / cryptography modules.
Perfect β that aligns really well with a philosophy of explicit, human-readable, lightweight persistence. You can get all the benefits of βfile-based stateβ without the overhead of a full database. Letβs break down the options and design patterns.
1οΈβ£ Candidate storage formats
| Format | Pros | Cons | Notes |
|---|---|---|---|
| JSON | ASCII/UTF-8, human-readable, widespread support, native in Python | No comments, limited types (dict, list, str, int, float, bool, None) | Perfect for configs, recent state, or CLI caches |
| TOML | Human-readable, supports nested tables, comments, standard in Python ecosystem | Slightly more verbose than JSON | Great for config files (like Python project pyproject.toml) |
| INI / ConfigParser | Simple, human-readable, native parser | Limited nesting, type inference poor | Good for very simple key/value config |
| YAML | Very readable, supports complex types | Needs PyYAML, can execute arbitrary code if not careful | More powerful, often overkill |
| SQLite (plaintext file) | Single file, queryable, standard Python support | Not as human-readable as JSON/TOML | Good for structured logs or tables, still lightweight |
| CSV | Human-readable, tabular data, universally supported | Only tabular, no nested structure | Good for lists of simple records |
Key takeaway: For CLI state that is inspectable, editable, and lightweight, JSON or TOML is usually the sweet spot.
-
Use JSON for runtime caches or ephemeral session data.
-
Use TOML for persistent, user-editable configuration (with comments).
2οΈβ£ Basic design pattern: lightweight file-backed state
File layout
~/.pipeline/
ββ state.json # runtime/ephemeral CLI state
ββ config.toml # user-editable configuration
ββ credentials.keyring # secure secrets handled separately
Example: JSON-backed CLI state
# pipeline/state.py
import json
from pathlib import Path
STATE_FILE = Path.home() / ".pipeline" / "state.json"
STATE_FILE.parent.mkdir(exist_ok=True)
def _read_state() -> dict:
if STATE_FILE.exists():
try:
return json.loads(STATE_FILE.read_text(encoding="utf-8"))
except json.JSONDecodeError:
return {}
return {}
def _write_state(state: dict):
STATE_FILE.write_text(json.dumps(state, indent=2), encoding="utf-8")
def get(key: str, default=None):
return _read_state().get(key, default)
def set(key: str, value):
state = _read_state()
state[key] = value
_write_state(state)
def delete(key: str):
state = _read_state()
state.pop(key, None)
_write_state(state)
Usage in your CLI:
from pipeline import state
# store ephemeral current project
state.set("current_project", "eds_to_rjn")
# retrieve it later
project = state.get("current_project")
β Advantages:
-
Fully human-readable.
-
Process-independent: survives multiple CLI runs.
-
Easy to inspect/debug (
cat ~/.pipeline/state.json).
Example: TOML for persistent configuration
# pipeline/config.py
import toml
from pathlib import Path
CONFIG_FILE = Path.home() / ".pipeline" / "config.toml"
CONFIG_FILE.parent.mkdir(exist_ok=True)
def load() -> dict:
if CONFIG_FILE.exists():
return toml.load(CONFIG_FILE)
return {}
def save(data: dict):
with CONFIG_FILE.open("w", encoding="utf-8") as f:
toml.dump(data, f)
Usage:
from pipeline import config
cfg = config.load()
cfg["default_project"] = "eds_to_rjn"
config.save(cfg)
β Advantages:
-
Supports comments, nested tables.
-
User can manually edit safely.
-
Perfect for βdefault project,β API endpoints, CLI flags.
3οΈβ£ Key points for security
-
Never store secrets in plain JSON/TOML.
Use keyring or encrypted storage for API keys, passwords:import keyring keyring.set_password("pipeline", "eds_api", "super_secret") token = keyring.get_password("pipeline", "eds_api") -
You can combine:
-
JSON/TOML for state/config.
-
Keyring for credentials.
-
Optional encrypted JSON/TOML if you want extra confidentiality.
-
4οΈβ£ Optional enhancements
-
Atomic writes to avoid corruption:
import tempfile import shutil def _write_state_atomic(data: dict): with tempfile.NamedTemporaryFile("w", delete=False) as tf: tf.write(json.dumps(data, indent=2)) temp_name = tf.name shutil.move(temp_name, STATE_FILE) -
Versioned state to allow migrations:
{ "_version": 1, "current_project": "eds_to_rjn" } -
Default fallback values if file missing or corrupt.
5οΈβ£ Takeaways
-
Lightweight ASCII file-based state = explicit, inspectable, portable, safe.
-
JSON β ephemeral CLI state.
-
TOML β persistent, editable configuration.
-
Keyring/cryptography β secure credentials.
-
Avoid module globals for mutable state β the only exception is immutable constants.
If you want, I can draft a full PipelineState manager that automatically:
-
Uses JSON for state,
-
TOML for config,
-
Keyring for secrets,
-
Provides a single
get/set/deleteAPI,
so your CLI commands can rely on it consistently without touching module globals.
Do you want me to do that?
Clayton 5
another option is ascii mosde-recent-backups locally avaialble, with files exported from postgres export or mariadb or whichever sql CLI/package. winget Postrgres.Postgres, yada yada yada. We are targetting typer, termux, ish alpine on iOS, python, macOS, linux, raspberry pi, etc - true cross platform solutions
this will ultimately be more modular, and more webapp ready given the database integration
Yes β exactly, and youβre thinking about it in a very sustainable way.
Hereβs how that reasoning holds up, and how you can make it both modular and cross-platform-safe across your environments (Typer CLI, Termux, iSH Alpine, macOS, Linux, Windows, Raspberry Pi):
π± 1. File-based state as the stable foundation
Using ASCII/plaintext state is ideal for:
-
Transparency: You can inspect the appβs data with any text editor.
-
Debuggability: No hidden state β if something breaks, you just
cat ~/.myapp/state.jsonor similar. -
Portability: Works everywhere Python runs, including very constrained environments (Termux, iSH, etc.).
-
Version control: You can include default configs or mock data in Git repos for reproducibility.
Lightweight file-based persistence fits the βglobal across importsβ role but stays explicit and traceable.
π§± 2. Recommended format hierarchy
| Use case | Suggested format | Notes |
|---|---|---|
| Simple scalar state or config | .toml / .ini |
Human-readable; good for configs, default state, paths. |
| Nested state / structured lists | .json |
Fast read/write; built-in; works across all OSs. |
| Tabular cache or export/import | .csv |
Easy to open in Excel or SQL tools; plays well with pandas. |
| Append-only event or backup logs | .ndjson (JSON Lines) |
Very easy to append atomically and replay later. |
| Versioned object storage | .sqlite or .db |
Built into Python; single-file DB; easier migration to Postgres later. |
πΎ 3. βMost recent backupsβ pattern
What you describe β keeping a few ASCII βlatestβ backup exports from a real SQL database β is actually the best hybrid approach.
Example pattern:
~/.local/share/myapp/backups/
2025-11-01T1200Z_export.csv
2025-11-01T1200Z_meta.json
latest_export.csv β symlink or copy of most recent
Then your app or web API can:
-
Use SQLite or Postgres for real queries.
-
Export to flat files (CSV/JSON) for durability and transparency.
-
Read the latest export as its lightweight working dataset.
That keeps a clean line between runtime cache (SQLite, Redis, or in-memory) and persistent snapshots (ASCII exports).
βοΈ 4. Implementation example (universal)
from pathlib import Path
import json
from datetime import datetime
APP_STATE_FILE = Path.home() / ".local" / "share" / "myapp" / "state.json"
APP_STATE_FILE.parent.mkdir(parents=True, exist_ok=True)
def load_state():
if APP_STATE_FILE.exists():
return json.loads(APP_STATE_FILE.read_text())
return {"last_sync": None, "projects": []}
def save_state(state):
APP_STATE_FILE.write_text(json.dumps(state, indent=2))
def update_last_sync():
state = load_state()
state["last_sync"] = datetime.utcnow().isoformat()
save_state(state)
This:
-
Is cross-platform safe (no registry, no keychain dependency).
-
Works offline on Termux, macOS, Alpine, Pi, etc.
-
Is web-ready, since the same structure can later be replaced by a database table.
π§© 5. Migration-ready design
Later, if you introduce a database (SQLite β Postgres β webapp), you can:
-
Keep the same schema.
-
Replace
load_state()/save_state()with SQL queries. -
Preserve backward compatibility via the same data folder and exports.
You donβt lose your βASCII historyβ; you just add richer query capability.
Would you like me to show a cross-platform state manager class (something like FileStateManager) that abstracts this pattern and can transparently switch between JSON, CSV, or SQLite depending on configuration?
do the python functions that i write need to know about statemanagement? i would how not, that it is obfuscated away. Worst case, setters can hold the reference logic.
Exactly β thatβs the right instinct. β
Your regular functions should not know about how or where state is persisted.
Thatβs the job of a state management layer β a mediator or faΓ§ade β which hides the file/database/remote complexity behind clean, predictable APIs.
Letβs unpack that properly:
π§ Design principle: "State is a concern, not a dependency"
Your functions should:
-
Accept arguments
-
Return values
-
Avoid side effects
They shouldnβt care how those values are stored or remembered β that belongs in one well-defined state manager.
So instead of this (bad coupling):
def record_run_time():
import json
from pathlib import Path
state_file = Path("~/.myapp/state.json").expanduser()
state = json.loads(state_file.read_text())
state["last_run"] = "now"
state_file.write_text(json.dumps(state))
You isolate that concern:
# app/state_manager.py
class FileStateManager:
def __init__(self, path):
self.path = path
self._state = self._load()
def _load(self):
try:
return json.loads(self.path.read_text())
except FileNotFoundError:
return {}
def get(self, key, default=None):
return self._state.get(key, default)
def set(self, key, value):
self._state[key] = value
self._save()
def _save(self):
self.path.write_text(json.dumps(self._state, indent=2))
Then your functional code is independent:
# app/tasks.py
def record_run_time(state_mgr):
state_mgr.set("last_run", "now")
And in your CLI, daemon, or web handler:
# app/main.py
from pathlib import Path
from app.state_manager import FileStateManager
from app.tasks import record_run_time
STATE_FILE = Path.home() / ".local" / "share" / "myapp" / "state.json"
state_mgr = FileStateManager(STATE_FILE)
record_run_time(state_mgr)
π Why this is good
-
Encapsulation: State is localized to one object or module.
-
Testability: You can mock or swap out the state layer with an in-memory dict.
-
Migration safety: You can replace file persistence with SQLite, Postgres, or Redis by just updating
FileStateManager. -
Thread/process safety: The layer can later add locks, caches, or sync logic.
-
Predictability: Functions always behave the same given the same inputs β no hidden persistence behavior.
πͺΆ Optional refinements
-
Use
@propertyorsetters/gettersto make state appear as attributes (state_mgr.last_run = ...). -
Add a
.sync()or.save()method for explicit persistence only when needed. -
Cache small read-only data in memory while writing out asynchronously.
So yes β youβre absolutely right:
βWorst case, setters can hold the reference logic.β
Thatβs the cleanest fallback. The functions themselves shouldnβt βknowβ anything about how persistence happens β only that there is a state interface.
Would you like me to show a unified StateManager interface that can transparently handle JSON, CSV, or SQLite under the same API (e.g., get(), set(), save()), so you can plug in different backends later?
Clayton 6
so show me a line that retrieves a configured value, which makes no inference to how the config is stored. unless it should.
like, calling env vars is an example that is usually made explicit without calling a setter method, but it could
Perfect β thatβs exactly the right question:
βCan I retrieve a configured value without knowing how itβs stored β unless I want to?β
Yes β thatβs the heart of clean configuration management.
Letβs start from the ideal usage (the one line youβre talking about) and work backward.
π§© Ideal usage (no knowledge of storage backend)
from pipeline.config import Config
plant_name = Config.get("default_plant_name")
Thatβs it.
No idea if it came from:
-
a
.envfile -
an environment variable
-
a
config.json -
a system-wide
/etc/override -
or even a dynamic SQLite config table
Just Config.get("key").
βοΈ The implementation pattern
This is the lightweight but extensible version β file-backed if you want, but backend-agnostic.
# pipeline/config.py
import os
import json
from pathlib import Path
from typing import Any
class Config:
"""Unified configuration accessor. Knows how to *find* config values, not where they're from."""
_cache: dict[str, Any] | None = None
_config_file = Path.home() / ".config" / "pipeline" / "config.json"
@classmethod
def _load(cls):
"""Lazy load from file if not yet cached."""
if cls._cache is None:
if cls._config_file.exists():
try:
cls._cache = json.loads(cls._config_file.read_text())
except json.JSONDecodeError:
cls._cache = {}
else:
cls._cache = {}
return cls._cache
@classmethod
def get(cls, key: str, default: Any = None) -> Any:
"""Retrieve a config value from environment or file."""
# 1. Check environment variables first
if key.upper() in os.environ:
return os.environ[key.upper()]
# 2. Check file cache
cfg = cls._load()
return cfg.get(key, default)
@classmethod
def set(cls, key: str, value: Any):
"""Write config value (file-based, not environment)."""
cfg = cls._load()
cfg[key] = value
cls._config_file.parent.mkdir(parents=True, exist_ok=True)
cls._config_file.write_text(json.dumps(cfg, indent=2))
π‘ Example behavior
# Environment variable has priority
export DEFAULT_PLANT_NAME="Maxson"
python -m pipeline.cli
>>> from pipeline.config import Config
>>> Config.get("default_plant_name")
'Maxson'
If the environment doesnβt define it, it falls back to ~/.config/pipeline/config.json:
{
"default_plant_name": "T.E. Maxson Plant",
"eds_base_url": "https://eds.memphistn.gov/api"
}
π§ Why this works well
| Concern | Where it lives |
|---|---|
| How configs are stored | Inside Config |
| How configs are accessed | Through a stable API |
| Function logic | Only calls Config.get() |
| Portability | Swap out Config for a DB or API-backed version later |
| Discoverability | Files still human-readable, ASCII-based |
Optional extensions (future-proofing)
You can later add:
@classmethod
def sources(cls) -> list[str]:
return ["env", "json", "sqlite"]
Or support merging:
Config.load_from("/etc/pipeline/config.json")
Or make a backend registry:
Config.register_backend("sqlite", SQLiteBackend(...))
So, your one-liner:
plant_name = Config.get("default_plant_name")
β¦is 100% backend-agnostic.
It βmakes no inference to how config is stored,β unless you explicitly look inside Config.
Would you like me to extend this example into a multi-backend version where you can hot-swap between JSON, TOML, or SQLite just by changing one line or environment variable (e.g., CONFIG_BACKEND=json|sqlite|env)?
Clayton 8
from pipeline.config import Config
plant_name = Config.get("default_plant_name")
i disagree with this
it looks like a singleton that has state that is carried on import
which is wrong, like we discussed about.
Great β thatβs an important distinction and you're right to push back.
The core of your objection is correct: anything that creates or holds mutable state at import time looks and behaves like a singleton, and that is precisely what you wanted to avoid. The solution is to provide a stateless accessor (or an explicitly-instantiated manager) so import does not create/hold runtime state.
Below are two clean, practical patterns you can pick from:
1) Stateless one-liner (no import-time state)
This gives you the convenience of a single-line call but guarantees no module-level state is created on import. Each call reads the authoritative sources (env first, then file), so there are no hidden caches.
# pipeline/config.py
import os
import json
from pathlib import Path
from typing import Any
_CONFIG_FILE = Path.home() / ".config" / "pipeline" / "config.json"
def _read_file() -> dict:
if _CONFIG_FILE.exists():
try:
return json.loads(_CONFIG_FILE.read_text(encoding="utf-8"))
except (json.JSONDecodeError, OSError):
return {}
return {}
def get(key: str, default: Any = None) -> Any:
"""
Stateless config getter.
Priority:
1) ENVIRONMENT VARIABLE (uppercased key)
2) config file (~/.config/pipeline/config.json)
3) default
"""
# 1) Env has precedence
env_key = key.upper()
if env_key in os.environ:
return os.environ[env_key]
# 2) Read file each call (no caching)
cfg = _read_file()
return cfg.get(key, default)
Usage:
from pipeline.config import get
plant_name = get("default_plant_name")
Pros:
-
No hidden state on import.
-
Deterministic: you always get current env/file state.
-
Simple and explicit.
Cons:
- Slight performance cost if you call it many times (reads file on each call). Usually negligible for CLI usage.
2) Explicit manager instance (opt-in caching, explicit lifetime)
When you do want caching for performance, create and pass an explicit manager object. This makes the lifetime and scope of cached state obvious (no surprise singletons).
# pipeline/config_manager.py
import os, json
from pathlib import Path
from typing import Any
class ConfigManager:
def __init__(self, path: Path | None = None, preload: bool = True):
self.path = path or (Path.home() / ".config" / "pipeline" / "config.json")
self._cache: dict | None = None
if preload:
self._load()
def _load(self):
if self._cache is None:
try:
self._cache = json.loads(self.path.read_text(encoding="utf-8"))
except Exception:
self._cache = {}
return self._cache
def get(self, key: str, default: Any = None) -> Any:
# env first
env_key = key.upper()
if env_key in os.environ:
return os.environ[env_key]
cfg = self._load()
return cfg.get(key, default)
def reload(self):
self._cache = None
self._load()
def set_and_persist(self, key: str, value: Any):
cfg = self._load()
cfg[key] = value
self.path.parent.mkdir(parents=True, exist_ok=True)
self.path.write_text(json.dumps(cfg, indent=2), encoding="utf-8")
Usage (explicit):
from pipeline.config_manager import ConfigManager
cfg = ConfigManager() # explicit, testable, disposable
plant_name = cfg.get("default_plant_name")
# when done, let cfg go out of scope; nothing is held globally
Pros:
-
Explicit cached lifetime and control (
reload(),set_and_persist()). -
No import-time singleton; you only create it when you want it.
-
Easier to unit-test and to inject into functions.
Cons:
- Requires creating/passing the object when you want caching (which is a feature, not a bug).
Comparison & Recommendation
-
If you want zero import-time state and minimal surprise: use the stateless
get()function (option 1). That gives your desired single-line call and is safe across imports/processes. -
If you need performance or explicit lifecycle, use the ConfigManager instance (option 2) and create it where you control scope (CLI startup, daemon main, or web app startup). This is explicit and testable β not a hidden singleton.
-
Never use a class-level cache or module-level mutable cache that is populated at import time β thatβs the pattern you rightly rejected.
Extra: A middle ground β stateless public API, explicit cached backend
If you want both the convenience of get() and the option to cache, provide both:
# pipeline/config_api.py
from .config import get as stateless_get
from .config_manager import ConfigManager
_default_manager = None
def get(key, default=None, use_cache=False):
global _default_manager
if use_cache:
if _default_manager is None:
_default_manager = ConfigManager()
return _default_manager.get(key, default)
return stateless_get(key, default)
This keeps import-time state minimal (_default_manager is None until requested) and makes caching an opt-in behavior. But note: even this creates a possible global once caching is requested β so prefer the explicit ConfigManager where possible.
If you want, I can:
-
Convert your existing
Configclass to the statelessget()pattern and show how to replace existing calls. -
Or scaffold a small
ConfigManager+ example usage in your Typermain()callback (so the manager is created once per CLI run and passed into subcommands viactx.obj).
Which would you prefer?
Clayton 9
I want my stuff to be mutale from multiple input or control sources. so if a user makes a change in cli and then in gui and then in cli, it all sticks, waterfall
Perfect β thatβs a solid requirement and an excellent mental model:
βIf the user changes something in the CLI, and then in the GUI, and then again in the CLI β everything should stay in sync.β
That implies true cross-process state, not per-import or per-process caches.
And it rules out Python-level singletons or module variables as a storage mechanism.
Letβs frame it cleanly.
π§ What youβre describing
You want a shared mutable configuration, visible to all user interfaces (CLI, GUI, daemon, web UI, etc.), that:
-
Can be updated by any of them.
-
Is immediately discoverable by others.
-
Persists across process boundaries.
-
Is text-based and human-readable (ASCII-first).
-
Works offline and cross-platform.
Thatβs file-based state synchronization β effectively a βlightweight config databaseβ that uses files as the single source of truth.
ποΈ The core idea: persistent file-backed config manager
Every interface talks through the same thin manager class, which reads and writes from a file (JSON, TOML, or YAML).
This file is the βtruth.β No global state, no Python singletons.
Example: shared_config_manager.py
import json
import os
import time
from pathlib import Path
from typing import Any
class SharedConfig:
"""Cross-process shared configuration manager."""
def __init__(self, path: Path | None = None):
self.path = path or (Path.home() / ".config" / "pipeline" / "shared_config.json")
self._last_load_time = 0
self._cache: dict[str, Any] = {}
self.reload() # initial load
def reload(self):
"""Reload config if file changed since last load."""
try:
mtime = os.path.getmtime(self.path)
if mtime > self._last_load_time:
self._cache = json.loads(self.path.read_text(encoding="utf-8"))
self._last_load_time = mtime
except FileNotFoundError:
self._cache = {}
return self._cache
def get(self, key: str, default: Any = None):
self.reload() # always get latest from disk
return self._cache.get(key, default)
def set(self, key: str, value: Any):
"""Update the shared config file (atomic write)."""
self.reload() # merge recent changes
self._cache[key] = value
tmp_path = self.path.with_suffix(".tmp")
self.path.parent.mkdir(parents=True, exist_ok=True)
tmp_path.write_text(json.dumps(self._cache, indent=2), encoding="utf-8")
os.replace(tmp_path, self.path)
self._last_load_time = os.path.getmtime(self.path)
def all(self):
self.reload()
return dict(self._cache)
π‘ Usage β fully synchronized across interfaces
CLI command:
from pipeline.shared_config_manager import SharedConfig
cfg = SharedConfig()
cfg.set("default_plant_name", "T.E. Maxson")
GUI app (DearPyGui, PySimpleGUI, etc):
cfg = SharedConfig()
print(cfg.get("default_plant_name")) # -> "T.E. Maxson"
Daemon or web API:
cfg = SharedConfig()
plant = cfg.get("default_plant_name")
If you change it in any process, all others see it within a fraction of a second (since they re-read on get()).
π§© Why this works beautifully
| Feature | Behavior |
|---|---|
| Cross-interface persistence | File is shared, readable everywhere. |
| Cross-process safety | Uses atomic file replace to avoid partial writes. |
| Discoverable / ASCII-first | Config file is plain JSON. |
| Versionable | You can easily git-track or back up. |
| No import-time state | Nothing is kept in module scope; each process opens and syncs. |
| Low overhead | Single file read/write per mutation; fine for CLI + GUI scale. |
π§ Advanced extensions (optional)
If you want this to evolve toward a more βdatabase-likeβ persistence model:
| Backend | Why use it | Notes |
|---|---|---|
| SQLite | Safe concurrent writes, still local file | Same API: use sqlite3 instead of JSON |
| Postgres / MariaDB | Multi-user, multi-machine sync | CLI & GUI can share data remotely |
| TinyDB / pickledb | Key/value JSON store with simple API | Great bridge between JSON and SQL |
| TOML | Human-readable config-style | Works great for mostly static settings |
You can even hot-swap between them with a uniform interface:
backend = os.getenv("PIPELINE_CONFIG_BACKEND", "json")
if backend == "sqlite":
from pipeline.state.sqlite_backend import SharedConfig
else:
from pipeline.state.json_backend import SharedConfig
β In summary
Youβre absolutely correct to reject hidden singletons.
This approach:
-
Keeps your architecture modular and honest.
-
Makes CLI, GUI, and daemons cooperate seamlessly.
-
Is βwebapp-readyβ later β your web server can just read/write the same JSON or SQLite file.
Would you like me to extend this SharedConfig system to support watching the file for live reloads (e.g., if the GUI updates the config, your CLI sees it instantly without re-run)? That can be done with a tiny cross-platform file watcher (watchdog or pure os.stat polling).
Clayton 10
what are the risks of instability and security and well-intentioned accidental destruction in this plaintext file based approach? How are risks in this architecture smartly managed, and are there still gaps in how the community addresses and manages the risks?
I feel like there is room for a plaintext database architecture that can be mutable and impact from multiple surfaces. But we dont want these to be attack surfaces or tripping hazards.
Absolutely β youβre thinking very carefully, and your instincts are spot-on. A mutable, cross-process, plaintext fileβbased state system is powerful, lightweight, and transparent β but it comes with real risks around stability, integrity, and security. Letβs go through them in depth and outline the mitigation strategies used in practice.
1οΈβ£ Core risks
a) Race conditions / corruption
-
Problem: Two processes (CLI + GUI, or multiple daemons) write to the same JSON/TOML/CSV file at the same time.
-
Consequence: File is partially written, becomes invalid JSON, or loses data.
-
Example: CLI writes
"last_run": "2025-11-01T16:00Z"while GUI is writing"theme": "dark"β file ends up truncated or only one write is preserved.
b) Accidental overwrites
-
Problem: A process reads an older version, updates it in memory, then writes back β overwriting changes made by another process in the meantime.
-
Consequence: Last-writer-wins problem; earlier updates are lost.
-
Example: User changes
default_plant_namein GUI, then CLI saves old cached value β GUI change is lost.
c) Human error
-
Problem: Since the file is editable, a user could delete keys, change types, or introduce syntax errors.
-
Consequence: Config may fail to parse, app crashes, or default/fallback behavior kicks in unexpectedly.
d) Security / leakage
-
Problem: Sensitive data in plaintext (API keys, passwords) can be read by any local user or backup system.
-
Consequence: Unauthorized access if machine is shared, compromised, or backed up to insecure locations.
e) File system issues
-
Problem: Disk full, corrupted filesystem, bad permissions, or antivirus locks file mid-write.
-
Consequence: Writes fail, files become corrupted, app misbehaves.
f) Cross-platform pitfalls
-
Problem: Path differences (
\vs/), line endings, filesystem case sensitivity, symbolic links, and atomicity of file operations. -
Consequence: Writes fail or overwrite unexpected files; atomic rename might behave differently.
2οΈβ£ How to manage risks smartly
a) Atomic writes
-
Always write to a temporary file first, then
os.replace(tmp, target)(or equivalent). -
Guarantees that either the old file remains intact or the new one fully replaces it.
-
Prevents partial corruption due to crash or interrupt.
b) Read-before-write merge
-
Before writing, reload the latest state from disk.
-
Merge changes rather than overwriting blindly.
-
Solves βlast-writer-winsβ problem in most small-scale apps.
c) Locking / concurrency control
-
For multiple processes, use:
-
File locks (
fcntlon Unix,msvcrton Windows) -
Lock files (
.lock) for simple coordination
-
-
Avoids simultaneous writes causing corruption.
-
For very low-frequency updates (CLI, GUI), simple polling + atomic writes is often sufficient.
d) Validation / schema enforcement
-
Use a JSON schema, Pydantic model, or simple type checks when loading.
-
Reject invalid files or fallback to defaults.
-
Protects against accidental user edits and syntax errors.
e) Backups / versioned snapshots
-
Keep previous N versions (
state.json.bak1,.bak2) in the same folder. -
Allows recovery if corruption occurs or a bad write happens.
-
Optionally implement timestamped snapshots:
2025-11-01T16:00Z.json.
f) Separation of concerns
-
Config/state vs credentials:
-
Store sensitive secrets in a keyring or encrypted store, never plaintext.
-
Config/state files contain only non-sensitive data.
-
-
Immutable constants: Keep static references separate from mutable state to avoid accidental overwrites.
g) Permissions
- Restrict file permissions (
600on Unix, ACLs on Windows) to avoid exposure to other users.
h) Cross-platform testing
-
Test on all target platforms (Windows, macOS, Linux, Termux/iSH) to verify:
-
Atomic write behavior
-
File locks
-
Path resolution
-
Unicode handling
-
3οΈβ£ Residual gaps / community challenges
Even with these mitigations, there are edge cases that are hard to completely eliminate:
| Gap | Why it exists | Mitigation |
|---|---|---|
| Multi-process collisions | File locks differ between OSs; networked/shared FS may not support atomic rename | Accept small probability, or switch to SQLite/Postgres for multi-user safety |
| Crash mid-write | Even atomic rename cannot fully prevent hardware failures | Frequent backups and checksum validation |
| Human tampering | Plaintext is editable | Versioned backups, schema validation, error fallback |
| Security on shared or cloud-synced files | Anyone with FS access can read | Keep secrets out of plaintext; use keyring or encrypted files |
| Cross-platform atomicity nuances | Windows vs Unix behaves differently | Test thoroughly; abstract atomic write in a utility function |
| Performance with very large files | JSON reads/writes whole file | For large datasets, switch to SQLite or chunked NDJSON |
4οΈβ£ Smart design patterns to adopt
-
Atomic writes + merge β ensures updates from multiple sources βwaterfallβ safely.
-
File-per-user, per-domain β prevents collisions across contexts.
-
Schema/validation β fails safe if file is corrupted.
-
Versioned snapshots β instant recovery.
-
Separate secrets β keyring/encryption.
-
Minimal in-memory caching β keep state mostly on disk to avoid stale views.
-
Optional backend swap β provide uniform API to switch to SQLite/Postgres when concurrency/performance demands grow.
β Key takeaway
Plaintext, multi-source, mutable state is feasible and very practical, but it requires:
-
Careful atomic write handling
-
Reload-before-write merge
-
Versioned backups
-
Validation against schema
-
Separation of secrets
-
Optional file locks for concurrency
If you follow these principles, the architecture is stable, recoverable, and reasonably secure, yet remains transparent and portable.
If you want, I can draw a concrete blueprint of a βplaintext waterfall config systemβ that:
-
Works across CLI, GUI, and daemons
-
Handles multi-process merges safely
-
Keeps versioned backups
-
Separates secrets
-
Is cross-platform
β¦all while keeping the API for your functions fully agnostic.
Do you want me to do that?
Chapter 11
Cross platform infers more than one user. Integration into the operating system and even social integration with other users on installations on other computers-
git merge is a dev problem. Keeping stuff that you dont want merged out of the push is a good idea.
i want to be cross platform. I understand that some local files for the lightweight plaintext database, those need to be able to rollout as the user uses the program, but that distribution should be clean, and ongoing use should be clean
draw a concrete blueprint of a βplaintext waterfall config system
Perfect β youβre essentially describing a cross-platform, multi-interface, user-safe, plaintext βwaterfallβ config system that behaves like a lightweight, local, versioned database, but is entirely file-based, transparent, and safely mutable across CLI, GUI, and daemons. Letβs blueprint this step by step.
ποΈ Blueprint: βPlaintext Waterfall Config Systemβ
1οΈβ£ Architecture overview
+--------------------------+
| CLI / GUI / Daemon |
| (read/write access) |
+-----------+--------------+
|
v
+--------------------------+
| Config Manager / API | <--- stateless public API for functions
| - get(key) |
| - set(key, value) |
| - all() |
| - watch() optional |
+-----------+--------------+
|
v
+--------------------------+
| Storage Layer (local) |
| - JSON / TOML / NDJSON |
| - Versioned backups |
| - Atomic writes |
| - Read-before-write merge|
+--------------------------+
Key design principles:
-
Stateless API for functions
Functions never touch the filesystem directly. They only callConfigManager.get()orset(). -
Atomic, mergeable storage
Always read the latest file before writing, merge changes, write atomically. -
Versioned backups
Every write produces a.bakor timestamped snapshot. -
Separate secrets
Sensitive info stored in keyring / encrypted file. -
Cross-platform paths
Standard OS-appropriate paths:-
macOS/Linux/Termux:
~/.config/myapp/ -
Windows:
%APPDATA%\myapp\
-
-
Optional file watching
For GUI / live dashboards: reload on change. -
Clean rollout / initialization
-
Default config file shipped with package (read-only)
-
User-specific copy created on first run
-
Updates only touch user copy, never the package files
-
2οΈβ£ Folder layout example
~/.config/myapp/
ββ shared_config.json # main mutable file
ββ shared_config.json.bak1 # versioned backups
ββ shared_config.json.bak2
ββ defaults.json # read-only defaults shipped with the package
ββ secrets.json.enc # optional encrypted secrets
Notes:
-
Defaults never overwritten.
-
User file is the βactive mutable DBβ.
-
Backups allow safe recovery if corruption occurs.
3οΈβ£ Data flow: βwaterfallβ
The waterfall pattern is:
-
Environment variables β highest priority (overrides everything)
-
User file β current mutable state
-
Defaults β fallback values if key missing
# Pseudocode
value = ENV.get("KEY") or USER_FILE.get("KEY") or DEFAULTS.get("KEY")
-
CLI/GUI writes only to USER_FILE.
-
Reads always merge waterfall: ENV > USER_FILE > DEFAULTS.
-
Each write triggers atomic backup and optional reload.
4οΈβ£ File write strategy (atomic + merge)
1. Load latest USER_FILE from disk
2. Merge incoming changes
3. Write to temp file: shared_config.json.tmp
4. Rename temp file to shared_config.json atomically
5. Create timestamped backup: shared_config_20251101T1600.json
-
Guarantees no partial writes.
-
Guarantees changes from other processes are preserved if read before write.
-
Guarantees historical state is recoverable.
5οΈβ£ API design (stateless for functions)
# pipeline/shared_config.py
from pathlib import Path
import json, os, time
class SharedConfig:
"""Cross-process mutable plaintext config system."""
def __init__(self, user_file: Path = None, defaults_file: Path = None):
self.user_file = user_file or self.default_user_path()
self.defaults_file = defaults_file or self.default_defaults_path()
self._cache = {} # optional in-memory cache for quick read
self._last_load = 0
self._load_defaults()
def default_user_path(self):
# cross-platform user config path
home = Path.home()
if os.name == "nt":
return Path(os.getenv("APPDATA")) / "myapp" / "shared_config.json"
return home / ".config" / "myapp" / "shared_config.json"
def default_defaults_path(self):
# shipped with package
return Path(__file__).parent / "defaults.json"
def _load_defaults(self):
try:
with open(self.defaults_file, encoding="utf-8") as f:
self._defaults = json.load(f)
except Exception:
self._defaults = {}
def _load_user_file(self):
try:
mtime = self.user_file.stat().st_mtime
if mtime > self._last_load:
with open(self.user_file, encoding="utf-8") as f:
self._cache = json.load(f)
self._last_load = mtime
except FileNotFoundError:
self._cache = {}
return self._cache
def get(self, key, default=None):
# waterfall: ENV > user_file > defaults > argument
env_val = os.environ.get(key.upper())
if env_val is not None:
return env_val
user_val = self._load_user_file().get(key)
if user_val is not None:
return user_val
return self._defaults.get(key, default)
def set(self, key, value):
# merge, atomic write, versioned backup
self._load_user_file()
self._cache[key] = value
tmp_file = self.user_file.with_suffix(".tmp")
self.user_file.parent.mkdir(parents=True, exist_ok=True)
with open(tmp_file, "w", encoding="utf-8") as f:
json.dump(self._cache, f, indent=2)
# atomic replace
os.replace(tmp_file, self.user_file)
# backup
backup_file = self.user_file.with_name(f"{self.user_file.stem}_{time.strftime('%Y%m%dT%H%M%S')}.json")
with open(backup_file, "w", encoding="utf-8") as f:
json.dump(self._cache, f, indent=2)
Usage from any interface:
from pipeline.shared_config import SharedConfig
cfg = SharedConfig()
# read
plant_name = cfg.get("default_plant_name")
# write
cfg.set("default_plant_name", "T.E. Maxson")
Key points:
-
CLI, GUI, daemon all share the same file.
-
Writes are atomic; reads always load latest.
-
Defaults and ENV variables provide waterfall.
-
Backups protect against accidents.
6οΈβ£ Security best practices
-
Secrets never in shared plaintext β use
keyringor encrypted file (secrets.json.enc). -
Restrict permissions on
shared_config.json(600Unix, ACL on Windows). -
Read-only defaults prevent accidental package changes.
-
Backups allow recovery if users mis-edit files.
7οΈβ£ Cross-platform roll-out and clean usage
-
Package defaults as part of Python package (
defaults.json). -
On first run, user file is auto-created if missing.
-
All runtime reads/writes go to user copy only, leaving package defaults untouched.
-
Backups ensure multi-interface safety.
-
Functions and business logic only use
cfg.get()andcfg.set()β no knowledge of storage, no import-time state.
β Result:
-
Fully mutable across CLI, GUI, daemons.
-
Transparent, human-readable, portable.
-
Safe against accidental overwrites.
-
Ready for incremental migration to SQLite or remote DB if needed.
-
Cross-platform and multi-user ready (within local OS boundaries).
If you want, I can extend this blueprint to show:
-
Optional live reload / file watch for GUI dashboards
-
Conflict resolution logic for multiple processes writing near-simultaneously
-
Encrypted secrets integration
β¦so you get a full production-ready βwaterfallβ system thatβs safe and modular.
Do you want me to do that next?
Chapter 13
perfect i love it. Teach me how.
with plaintext file storage, we can really riff. to demonstrate the potential, let's build a simulataneous rust portion of the software, which can access and traverse the database
Ahhh yes β now weβre talking about cross-language, plaintext-backed mutable state. This is extremely powerful because JSON/TOML/NDJSON/CSV are universally readable, so Rust, Python, or any other language can talk to the same βwaterfall configβ database without locks or complex IPC.
Letβs break this into steps and teach you the practical approach.
1οΈβ£ Core idea
You have a single source of truth: a plaintext file (JSON, NDJSON, or TOML) that acts as a mutable, multi-interface database.
Everything else is just an accessor layer:
-
Python reads/writes through
SharedConfig -
Rust can read/write the same file using
serde_jsonortoml -
CLI, GUI, daemon, web API all share the same file
-
Waterfall logic is universal: ENV β user file β defaults
2οΈβ£ Design choices for cross-language plaintext DB
| Choice | Pros | Cons |
|---|---|---|
| JSON | Native in Python, Rust (serde_json), JS |
Single file atomic write needed |
| NDJSON (newline-delimited JSON) | Append-only, streamable | Slightly more complex reads |
| TOML | Human-readable, hierarchical | Less universal than JSON |
| CSV / TSV | Good for tabular data | Poor for hierarchical structures |
β For our use case: JSON β human-readable, easy atomic writes, universal support.
3οΈβ£ Python side: SharedConfig recap
cfg = SharedConfig() # Python manager
cfg.set("default_plant_name", "T.E. Maxson")
cfg.get("default_plant_name") # always waterfall + latest file
-
Writes are atomic.
-
Reads always load latest from disk.
-
Backups for safety.
4οΈβ£ Rust side: Traversing & mutating the JSON DB
Goal: Rust can read/write the same JSON file safely, respecting the waterfall.
a) Setup
# Cargo.toml
[dependencies]
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
chrono = "0.4" # optional, for timestamped backups
fs_extra = "1.3" # optional, for atomic moves
b) Basic Rust accessor (atomic + merge)
use serde::{Deserialize, Serialize};
use serde_json::{Value, Map};
use std::fs;
use std::path::Path;
use std::collections::HashMap;
#[derive(Debug, Serialize, Deserialize)]
pub struct SharedConfig {
pub path: String,
cache: HashMap<String, Value>,
}
impl SharedConfig {
pub fn new(path: &str) -> Self {
let mut sc = SharedConfig {
path: path.to_string(),
cache: HashMap::new(),
};
sc.load();
sc
}
fn load(&mut self) {
let p = Path::new(&self.path);
if p.exists() {
let text = fs::read_to_string(&self.path).unwrap_or_else(|_| "{}".to_string());
self.cache = serde_json::from_str(&text).unwrap_or_default();
} else {
self.cache = HashMap::new();
}
}
pub fn get(&mut self, key: &str) -> Option<Value> {
self.load(); // reload latest
self.cache.get(key).cloned()
}
pub fn set(&mut self, key: &str, value: Value) {
self.load(); // merge latest changes
self.cache.insert(key.to_string(), value);
// atomic write
let tmp_path = format!("{}.tmp", &self.path);
fs::write(&tmp_path, serde_json::to_string_pretty(&self.cache).unwrap()).unwrap();
fs::rename(tmp_path, &self.path).unwrap();
// optional: create timestamped backup
// let backup_path = format!("{}_{}.json", &self.path, chrono::Utc::now().format("%Y%m%dT%H%M%S"));
// fs::write(backup_path, serde_json::to_string_pretty(&self.cache).unwrap()).unwrap();
}
}
c) Usage in Rust
fn main() {
let mut cfg = SharedConfig::new("/home/user/.config/myapp/shared_config.json");
// read value
let plant_name = cfg.get("default_plant_name");
println!("Plant Name: {:?}", plant_name);
// write value
cfg.set("default_plant_name", serde_json::json!("T.E. Maxson"));
// read again to confirm
let updated = cfg.get("default_plant_name");
println!("Updated: {:?}", updated);
}
5οΈβ£ Waterfall logic in Rust
To replicate the Python ENV β user file β defaults waterfall:
use std::env;
pub fn get_with_waterfall(cfg: &mut SharedConfig, key: &str, default: &str) -> String {
// 1) ENV
if let Ok(val) = env::var(key.to_uppercase()) {
return val;
}
// 2) user file
if let Some(val) = cfg.get(key) {
if let Some(s) = val.as_str() {
return s.to_string();
}
}
// 3) defaults (hardcoded or shipped JSON)
default.to_string()
}
6οΈβ£ Safety & stability notes
-
Atomic writes in Rust & Python β reduces corruption risk.
-
Read-before-write merge β prevents last-writer-wins destruction.
-
Backups β optional but recommended.
-
Cross-platform paths β use
dirscrate in Rust for user config folder. -
Secrets separate β
keyringor encrypted JSON.
7οΈβ£ Demo idea
You can now have:
-
Python CLI: set values
-
Python GUI: read & set values live
-
Rust service: read config & compute, optionally update
-
All share one JSON file, with versioned backups
β This proves the cross-language potential of plaintext waterfall config.
8οΈβ£ Next steps / advanced ideas
-
Watch file for live updates in GUI or Rust (
notifycrate in Rust,watchdogin Python) β waterfall is truly live. -
Conflict resolution: timestamps per key β last-writer wins per key, not whole file.
-
NDJSON append mode for append-only logs/history of changes.
-
Optional SQLite backend with same API if performance grows.
If you want, I can draw a full visual blueprint showing Python CLI, GUI, Rust service, backups, and waterfall behavior, so you can see exactly how everything interacts β essentially a complete cross-platform architecture diagram for your plaintext DB system.
Do you want me to do that next?
Do it.
Perfect! Letβs visualize the full cross-platform plaintext waterfall config system with Python CLI, Python GUI, Rust service, backups, and waterfall behavior. Iβll break it into layers, flows, and interactions.
πΌοΈ Architecture Diagram (Textual / Logical)
βββββββββββββββββββββββββββββββββββββββββββββββββ
β ENVIRONMENT VARIABLES β
β (Highest priority overrides everything) β
βββββββββββββββββββββββββββββββββββββββββββββββββ
β
βΌ
βββββββββββββββββββββββββββββββββββββββββββββββββ
β DEFAULTS FILE (JSON) β
β - Shipped with package β
β - Read-only, never modified β
βββββββββββββββββββββββββββββββββββββββββββββββββ
β
βΌ
βββββββββββββββββββββββββββββββββββββββββββββββββ
β USER CONFIG FILE (JSON) β
β - ~/.config/myapp/shared_config.json β
β - Writable by Python CLI / GUI / Rust β
β - Atomic writes + versioned backups β
β - Read-before-write merge β
β - Optional per-key timestamps for conflict β
βββββββββββββββββββββββββββββββββββββββββββββββββ
β
βΌ
βββββββββββββββββββββββββββββββββββββββββββββββββ
β SHARED CONFIG MANAGER / API β
β - Python: SharedConfig class β
β - Rust: SharedConfig struct β
β - Methods: get(key), set(key, value), all() β
β - Stateless interface for all functions β
βββββββββββββββββββββββββββββββββββββββββββββββββ
β β β
β β β
βΌ βΌ βΌ
βββββββββββββββββ βββββββββββββββββ βββββββββββββββββ
β Python CLI β β Python GUI β β Rust Service β
β - Reads/Writesβ β - Reads/Writesβ β - Reads/Writesβ
β - Waterfall β β - Waterfall β β - Waterfall β
β - Commands β β - Live reload β β - Optional NDJSON append logs β
βββββββββββββββββ βββββββββββββββββ βββββββββββββββββ
π§ Waterfall Behavior
Priority order when retrieving a value:
ENV VARIABLES
β
βΌ
USER CONFIG FILE (latest)
β
βΌ
DEFAULTS FILE (shipped)
Explanation:
-
ENV VARIABLES: Can override per-run (useful for testing, deployment).
-
USER CONFIG FILE: Mutable, shared across all interfaces, atomic writes, versioned backups.
-
DEFAULTS FILE: Always fallback values, never overwritten.
-
Writing always updates USER CONFIG FILE.
-
Reading merges waterfall automatically.
-
Functions using
cfg.get()never know about storage or ENV β stateless API.
π Cross-process / Cross-language Flow
Example Scenario:
-
Python CLI sets
default_plant_nameβ writes toshared_config.json. -
Python GUI reloads β reads latest JSON, shows updated name.
-
Rust service reads same JSON β sees same value, optionally updates another key.
-
Backup created with timestamp:
shared_config_20251101T1600.json. -
If a GUI accidentally deletes a key β backup allows restore.
All interfaces always see latest committed state.
ποΈ File System Layout
~/.config/myapp/
ββ shared_config.json # active mutable config
ββ shared_config_20251101T1600.json # backup snapshot
ββ shared_config_20251101T1630.json # backup snapshot
ββ defaults.json # package defaults, read-only
ββ secrets.json.enc # encrypted secrets (keyring optional)
Notes:
-
Each backup preserves history.
-
Secrets are never stored in plaintext
shared_config.json. -
Cross-platform paths are handled via
Path.home(),%APPDATA%, ordirscrate in Rust.
π‘οΈ Stability & Safety Features
| Feature | How it works |
|---|---|
| Atomic writes | Write temp file, then rename β prevents partial writes |
| Read-before-write merge | Loads latest file before any write β prevents last-writer-wins corruption |
| Backups | Timestamped JSON backups per write β recovery from human errors |
| Waterfall priority | ENV > USER FILE > DEFAULTS β ensures consistent overrides |
| Cross-language API | Python SharedConfig class, Rust SharedConfig struct β same file, same API |
| Secrets | Stored separately, optionally encrypted β reduces attack surface |
| Versioned defaults | Defaults shipped in package, never modified β safe rollouts |
β‘ Optional Advanced Features
-
Live reload for GUI / dashboard:
-
Python:
watchdogobservesshared_config.jsonβ triggers reload -
Rust:
notifycrate watches file β refresh cache
-
-
Conflict resolution per key:
-
Keep
last_modifiedtimestamp per key -
Resolve conflicts automatically in multi-process updates
-
-
NDJSON logs / append-only changes:
- Could store history of writes for auditing or undo
-
Migration to SQLite or remote DB:
- API stays the same β you can swap storage backend without changing business logic
π‘ Key Principles
-
Stateless access: Functions only use
cfg.get()/cfg.set()β storage invisible -
Cross-process safety: Atomic writes + read-before-write merge
-
Recoverable: Backups for every write
-
Cross-language: JSON/TOML readable in Python, Rust, JS, etc.
-
Cross-platform: Uses OS-standard config directories
George, this is essentially a production-ready blueprint for your βplaintext waterfall config systemβ:
-
Mutable across CLI, GUI, Rust, daemons
-
Waterfall logic for overrides
-
Versioned backups to prevent accidental destruction
-
Secrets isolated and secure
-
Cross-platform compatible
If you like, the next step is to make this interactive:
- A tiny demo where Python CLI sets a value, Python GUI shows it live, and Rust service reads it and appends a log entry, all sharing the same JSON, demonstrating true cross-language waterfall behavior.
Do you want me to build that demo next?