V0.9.10

[bartvanbenthem]

What's New

Exponential backoff on poll failures

watch_external no longer retries immediately on error. Failed polls now wait
using exponential backoff: the retry delay starts at the base interval,
doubles on each consecutive failure, and is capped at interval × 32.
A successful poll resets the wait back to interval.

Previously, a transient failure caused an immediate retry on the next tick with
only a warning log. Now the watcher backs off progressively, reducing noise and
load during extended outages.

New WatchConfig type and watch_external_with_config entry point

WatchConfig exposes interval and max_backoff as explicit fields and is
constructed with a fluent builder:

use std::time::Duration;
use koprs_external::watcher::WatchConfig;

let config = WatchConfig::new(Duration::from_secs(30))
    .with_max_backoff(Duration::from_secs(300)); // cap retries at 5 min

watch_external_with_config accepts a WatchConfig instead of a bare
Duration, giving full control over the retry ceiling:

let _handle = watch_external_with_config(poller, config, tx);

watch_external remains unchanged as a convenience wrapper; it calls
watch_external_with_config with WatchConfig::new(interval) and a default
max_backoff of interval × 32.

Public re-exports

WatchConfig and watch_external_with_config are now re-exported from the
crate root alongside the existing ExternalEvent and watch_external.

use koprs_external::{ExternalEvent, WatchConfig, watch_external, watch_external_with_config};

Correct feature flag name in documentation

The object-store feature is "object-store", not "s3". The README and
code examples have been corrected.

# correct
koprs-external = { version = "0.9.1", features = ["object-store"] }

Internal changes

• watcher.rs: replaced the tokio::time::interval ticker with explicit
  sleep calls so backoff waits can vary between iterations.
• store.rs: removed duplicate inline doc examples that duplicated the
  README; module-level and struct-level docs now point to the crate README for
  backend-specific setup.
• lib.rs: doc-link syntax updated ([crate::watcher::ExternalSource] →
  [watcher::ExternalSource]) to fix cross-reference resolution.
• tests/watcher.rs: added FlakySource — a test double that fails a
  configurable number of times then succeeds — covering the backoff recovery
  path. Three new async tests verify recovery after N errors, survival through
  five consecutive failures, and watch_external_with_config behaviour.
• tests/watcher.rs: two unit tests cover WatchConfig construction:
  default max_backoff equals interval × 32, and with_max_backoff
  overrides the default correctly.

Migration

watch_external is source-compatible. No changes required for existing callers.

To set a custom backoff ceiling, switch to watch_external_with_config:

// before
let _handle = watch_external(poller, Duration::from_secs(30), tx);

// after — custom ceiling
let config = WatchConfig::new(Duration::from_secs(30))
    .with_max_backoff(Duration::from_secs(300));
let _handle = watch_external_with_config(poller, config, tx);