Health Check Improvements

[stevensJourney]

Overview

The PowerSync service uses a probing system to communicate health check statuses. Internally, the probe state is updated when the service becomes ready or active. This state is maintained in memory and can be exposed externally via the filesystem or HTTP endpoints.

Previously, probe state was always exposed via the filesystem by writing timestamps to .probes/startup, .probes/ready, and .probes/poll. This required the service to run with write access to the filesystem, which isn't always feasible or recommended. There was no way to disable filesystem probes.

In addition, the same probe state was exposed via HTTP routes, but only if the RouterEngine started an HTTP server. This occurred only in API and UNIFIED modes. In SYNC mode, the only way to access probe state externally was through the filesystem.

What's new

This PR introduces configurable probe types through the PowerSync configuration file. You can now enable or disable probe outputs via YAML:

  healthcheck:
    probes:
      use_filesystem: true
      use_http: true

The specified probe_types determine how probe state is exposed. Selecting http will now start an HTTP server even when running in SYNC mode.

Backwards compatibility
If no healthchecks configuration is provided, the service retains its previous behavior.

Implementation

Internally this moves some configuration from the service runner to a new shared module. This should remove some minor duplication throughout our hosted codebases.

[changeset-bot]

🦋 Changeset detected

Latest commit: 2aec7ee

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 15 packages

Name	Type
@powersync/service-core	Minor
@powersync/service-image	Minor
@powersync/service-types	Minor
@powersync/lib-services-framework	Minor
@powersync/service-module-core	Minor
@powersync/service-core-tests	Patch
@powersync/service-module-mongodb-storage	Patch
@powersync/service-module-mongodb	Patch
@powersync/service-module-mysql	Patch
@powersync/service-module-postgres-storage	Patch
@powersync/service-module-postgres	Patch
test-client	Patch
@powersync/lib-service-postgres	Patch
@powersync/service-rsocket-router	Patch
@powersync/lib-service-mongodb	Patch

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