Add Prometheus /metrics endpoint

[jamescmartinez]

This PR adds a Prometheus metrics endpoint to the dashboard and the supporting backend queries to power it.

GET /metrics on the dashboard:

# HELP openworkflow_workflow_runs Current count of workflow runs in each status.
# TYPE openworkflow_workflow_runs gauge
openworkflow_workflow_runs{status="pending"} 0
openworkflow_workflow_runs{status="running"} 0
openworkflow_workflow_runs{status="sleeping"} 0
openworkflow_workflow_runs{status="completed"} 0
openworkflow_workflow_runs{status="failed"} 0
openworkflow_workflow_runs{status="canceled"} 0

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/openworkflowdev/openworkflow/@openworkflow/cli@327

npm i https://pkg.pr.new/openworkflowdev/openworkflow/@openworkflow/dashboard@327

npm i https://pkg.pr.new/openworkflowdev/openworkflow@327

commit: 83fd3e0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[Copilot]

Pull request overview

This PR adds Prometheus metrics support to the OpenWorkflow dashboard by introducing a new /metrics endpoint that exposes workflow run counts grouped by status. The implementation includes backend aggregation queries, a metrics server handler, comprehensive test coverage, and user documentation.

Changes:

• Added countWorkflowRuns() method to Backend interface with implementations for PostgreSQL and SQLite
• Created /metrics endpoint in dashboard that serves Prometheus exposition format
• Added comprehensive documentation for Prometheus integration with alert examples

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/openworkflow/backend.ts	Added WorkflowRunCounts type, countWorkflowRuns interface method, and toWorkflowRunCounts helper function for status aggregation
packages/openworkflow/sqlite/backend.ts	Implemented countWorkflowRuns with SQLite GROUP BY query
packages/openworkflow/postgres/backend.ts	Implemented countWorkflowRuns with PostgreSQL GROUP BY query
packages/openworkflow/backend.test.ts	Added unit tests for toWorkflowRunCounts function covering legacy "succeeded" status handling
packages/openworkflow/backend.testsuite.ts	Added integration tests for countWorkflowRuns covering empty state, status grouping, and transitions
packages/dashboard/src/lib/metrics.server.ts	Created metrics server handler using prom-client to generate Prometheus exposition format
packages/dashboard/src/lib/metrics.server.test.ts	Added tests for metrics endpoint covering format validation, caching behavior, and error handling
packages/dashboard/src/routes/metrics.ts	Added /metrics route definition
packages/dashboard/src/routeTree.gen.ts	Auto-generated route tree updates for new metrics route
packages/dashboard/package.json	Added prom-client v14.2.0 dependency
packages/docs/docs/prometheus.mdx	New documentation page with setup instructions, metrics reference, and PromQL alert examples
packages/docs/docs/production.mdx	Added reference to Prometheus metrics documentation
packages/docs/docs/dashboard.mdx	Added reference to Prometheus metrics documentation
packages/docs/docs.json	Added prometheus.mdx to documentation navigation
package-lock.json	Lock file updates for prom-client and dependencies (bintrees, tdigest)

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 14 out of 15 changed files in this pull request and generated 2 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated no new comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.