Wiring Components

This is how to wire one component’s data into another. The composition grammar these patterns build on — phases, steps, gate, onFailure — lives in Composition & Wiring.

Cross-stack outputs

When one component’s stack exports a value another needs, the consumer imports it. The graph resolves it, replacing the describe-stacks | jq glue a pipeline would otherwise carry.

export const searchService: Component = {
  name: "search-service",
  dependsOn: ["shared-alb"],
  deploy: [
    phase("Apply", [cfnDeploy({ template: "archive:search.template.json", inputs: { ...sharedAlb.outputs } })]),   // listener ARN, cluster ARN, subnets, …
  ],
};

chant graph --stacks orders shared-alb before the service and wires its outputs. See Multi-Stack Projects for the underlying stackOutput mechanism.

examples/adopt-alb-services is the runnable version of this exact pattern: a bespoke two-service ALB pipeline — describe-stacks | jq glue and all, kept as before/.gitlab-ci.yml — adopted as three build.json components a single driver runs.

Cross-component outputs

Components also wire by artifact, not just by stack output. A producer publishes an artifact; a consumer references it as @<component>.publish.uri (or .digest / .key). dependsOn orders the producer first; the graph resolves the reference into the consumer’s step.

The example illustrates the wiring — its jvm-build and publish-artifact verbs are not yet implemented (the cross-component reference resolution is what ships today):

// producer — a JAR published to S3, publish-only deploy
export const jarLib: Component = {
  name: "jar-lib",
  build: jvmBuild({ tool: "maven", path: ".", into: "archive" }),
  deploy: [phase("Publish", [publishArtifact({ from: "archive", to: "$env.s3" })])],   // → @jar-lib.publish.uri
};

// consumer — an EMR job that reads the JAR
export const emrJob: Component = {
  name: "emr-job",
  dependsOn: ["jar-lib"],
  deploy: [
    phase("Submit", [emrStartJobRun({ jar: "@jar-lib.publish.uri", args: [/* … */] })]),
    phase("Verify", [waitJob({ runId: "@Submit.runId" })]),
  ],
};

Both wirings, one resolver

Cross-stack outputs and cross-component artifact outputs are resolved the same way — by the graph, never by orchestrator code. That is what keeps the driver generic across an unbounded set of components.

Read next

• Composition & Wiring — the composition grammar and fan-out, which these two wiring mechanisms build on.
• examples/adopt-alb-services — a bespoke multi-service ALB pipeline adopted onto the component model, before and after, runnable end to end.
• Build Archive — where a producer’s artifact lives before it is published.