IntervalParallelHTTP

Monitor services in parallel

Run independent endpoint checks at the same time, then publish one health result after every check has settled.

This workflow uses a durable five-minute interval. The <parallel> group gives each endpoint its own step and runs all three checks concurrently. A final step reads those durable outputs and produces a compact report.

The workflow

WOML

<woml>
  <workflow
    id="service-health"
    name="Service health"
    description="Check public WOML endpoints and summarize their health."
    version="1.0.0"
  >
    <config concurrency="1" timeout="2m" />

    <triggers>
      <interval id="poll" every="5m" on-missed="skip" />
    </triggers>

    <steps>
      <parallel id="checks" name="Check endpoints" concurrency="3" on-error="wait-all">
        <step id="website" name="Check woml.org" retry="3" retry-backoff="exponential">
          <script>
            const response = await services.http.request({
              url: "https://woml.org",
              responseType: "text",
              timeout: "10s",
              acceptedStatus: { minimum: 100, maximum: 599 }
            }, { name: "check-woml-website" });

            return { name: "website", status: response.status, healthy: response.ok };
          </script>
        </step>

        <step id="repository" name="Check GitHub repository" retry="3" retry-backoff="exponential">
          <script>
            const response = await services.http.request({
              url: "https://github.com/dali-benothmen/woml",
              responseType: "text",
              timeout: "10s",
              acceptedStatus: { minimum: 100, maximum: 599 }
            }, { name: "check-woml-repository" });

            return { name: "repository", status: response.status, healthy: response.ok };
          </script>
        </step>

        <step id="package" name="Check npm package" retry="3" retry-backoff="exponential">
          <script>
            const response = await services.http.request({
              url: "https://registry.npmjs.org/woml-cli/latest",
              timeout: "10s",
              acceptedStatus: { minimum: 100, maximum: 599 }
            }, { name: "check-woml-package" });

            return { name: "package", status: response.status, healthy: response.ok };
          </script>
        </step>
      </parallel>

      <step id="report" name="Build health report">
        <script>
          const checks = [
            context.steps.website,
            context.steps.repository,
            context.steps.package
          ];

          return {
            healthy: checks.every((check) => check.healthy),
            checkedAt: context.payload.triggeredAt,
            checks
          };
        </script>
      </step>
    </steps>
  </workflow>
</woml>

Run it

Save the file as service-health.woml, validate it, and keep it active for scheduled checks.

Terminal

woml check service-health.woml
woml run service-health.woml

The parallel group has no aggregate output of its own. Each child publishes its result under context.steps, and the downstream report step deliberately defines the final shape.