version-check

A lightweight, opt-in version checking library for Mozilla CLI tools.

Features

Opt-in only: Only checks when MOZTOOLS_UPDATE_CHECK=1 is set
Non-blocking: Runs in background thread, never delays program startup
Cached: Checks at most once per 24 hours per tool
Shared cache: All tools share ~/.mozbuild/tool-versions.json
Silent failures: Network errors don't affect program operation
Thread-safe: Safe for concurrent access

Usage

Add to your Cargo.toml:

[dependencies]
version-check = { path = "../foxtail/version-check" }

In your main.rs:

fn main() -> Result<()> {
    let version_checker = version_check::VersionChecker::new(
        "your-tool-name",
        env!("CARGO_PKG_VERSION"),
    );
    version_checker.check_async();

    let result = run();

    version_checker.print_warning();

    result
}

fn run() -> Result<()> {
    // Your actual program logic here
    Ok(())
}

How It Works

At program startup, if MOZTOOLS_UPDATE_CHECK=1 is set, spawn a background thread
The thread checks the cache file (~/.mozbuild/tool-versions.json)
If the cache is recent (< 24 hours), use cached data
Otherwise, query crates.io API: https://crates.io/api/v1/crates/<name>
Update the cache with the latest version info
At program exit, print a warning if a newer version is available

Warning Format

When a newer version is available, users see:

Note: A newer version of socorro-cli is available (0.2.0 > 0.1.0)
      Run: cargo binstall socorro-cli

Cache Format

The cache file at ~/.mozbuild/tool-versions.json contains:

{
  "socorro-cli": {
    "last_check": 1234567890,
    "latest": "0.2.0"
  },
  "treeherder-cli": {
    "last_check": 1234567890,
    "latest": "0.1.0"
  }
}

Testing

To enable version checking:

export MOZTOOLS_UPDATE_CHECK=1
socorro-cli crash --help

To disable (default):

unset MOZTOOLS_UPDATE_CHECK
socorro-cli crash --help

Configuration

Cache location: ~/.mozbuild/tool-versions.json
Cache validity: 24 hours
Network timeout: 5 seconds
User-Agent: {tool-name}/version-check

Implementation Details

Uses reqwest with blocking client for HTTP requests
Uses serde_json for cache file serialization
Thread-safe via Arc<Mutex<Option<String>>>
Silently fails on any error (network, I/O, parsing)
Never blocks program execution

moz-cli-version-check 0.1.0