CIPipeline

CI/CD Pipeline

A durable CI/CD pipeline modelled as a Strand workflow. If a build worker crashes during any stage, the pipeline resumes from the last completed step on restart — no work is lost, no stage runs twice.

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What it demonstrates

Strand feature	Where
Parallel activity fan-out	Lint + unit tests + security scan run simultaneously via async let
Automatic retry	UnitTestActivity fails on attempt 1, passes on attempt 2
Signal-based approval gate	context.condition suspends until an approve signal arrives
WorkflowSignal	Typed handle.signal(CIPipelineWorkflow.Approve.self, payload:)
Durability under crash	Kill the process at any stage; restart resumes from the last checkpoint

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Pipeline stages

[ 1 ] Checkout          clone the repo
[ 2 ] Quality Gates     lint + unit tests + security scan (all parallel)
[ 3 ] Build             compile release artifact
[ 4 ] Approval Gate     wait for an operator to send the "approve" signal
[ 5 ] Deploy            rolling update across instances

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Prerequisites

• PostgreSQL 15+ on localhost:5499

psql "postgresql://strand:strand@localhost:5499/strand_dev" -f ../../../strand.sql

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Quick start

cd Examples
swift run CIPipeline

The demo sends an approval signal automatically after ~18 s so the pipeline runs end-to-end without manual intervention.

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Sending the approval signal manually

To try the approval gate interactively, comment out the auto-approve Task in CIPipelineExample.swift, then send the signal from a second terminal once the pipeline reaches stage 4:

// In your own code or the REPL:
let client = StrandClient(postgres: postgres, queue: "ci-pipeline",
                          namespace: "ci-pipeline-demo")
let handle = client.workflowHandle(id: taskID, as: CIPipelineWorkflow.self)
try await handle.signal(
    CIPipelineWorkflow.Approve.self,
    payload: ApprovalDecision(approved: true, approver: "alice")
)

Or from the Loom dashboard: open the task → Send Signal:

Field	Value
Signal name	approve
Payload	{"approved": true, "approver": "alice"}

To reject the deployment: {"approved": false, "approver": "alice"}.

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Crash recovery demo

Kill the process at any point during the run (Ctrl-C). Restart with swift run CIPipeline. Because each stage is a checkpointed activity, the pipeline resumes from the last completed stage — try killing during the Build stage and watch it skip Checkout and Quality Gates on restart.