Shlink on Cloud Run — Lab Guide

📖 Configuration Guide

Overview

Estimated time: 45–90 minutes

Shlink is a self-hosted, open-source URL shortener with detailed visit analytics and a full REST API. This lab takes you through the full operational lifecycle of the Shlink on Cloud Run module on Google Cloud: deploy it, access and verify it, run it day-to-day, observe it, diagnose common problems, and tear it down.

The lab focuses on operating the Cloud Run module and the Google Cloud platform, not on Shlink product features. For the complete list of provisioned services and every configuration input (organised by group), see the Configuration Guide — this lab deliberately does not duplicate that detail so it stays accurate over time.

Objectives

By the end of this lab you will be able to:

• Deploy the module from the RAD platform and locate the resources it provisions.
• Access and verify the running service through its health endpoint and REST API.
• Retrieve the auto-generated API key and create your first short URL.
• Perform day-2 operations — inspect, scale, update, and manage secrets and backups.
• Observe the service with Cloud Logging and Cloud Monitoring.
• Diagnose and resolve the most common deployment and runtime issues.
• Tear the deployment down cleanly.

Prerequisites

• Services_GCP deployed in the target project (provides the VPC, Cloud SQL, Artifact Registry, and shared service accounts this module depends on).
• A Google Cloud project with billing enabled.
• gcloud CLI authenticated: gcloud auth login and gcloud auth application-default login.
• Project Owner (or equivalent) IAM on the project.
• RAD platform access with permission to deploy modules into the project.

Set these shell variables once; every task below reuses them:

export PROJECT="<your-gcp-project-id>"
export REGION="us-central1"          # the region you deploy into

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Task 1 — Deploy the module [Automated]

1. Click Deploy in the RAD platform top navigation, open Shlink (Cloud Run) from the Platform Modules list to start configuration, set project_id, and review the inputs. Configure only what you need — the Configuration Guide documents every input by group, with defaults. Review the estimated cost (if credits are enabled) and click Deploy, which opens the deployment status page with real-time logs.

2. The platform provisions the Cloud Run service, a Cloud SQL (PostgreSQL 15) database with its Secret Manager secrets (DB password plus the auto-generated INITIAL_API_KEY), builds and mirrors the container image into Artifact Registry, and runs a one-shot database-initialisation job. Shlink needs no NFS share or GCS bucket — all state lives in PostgreSQL. First deploys take roughly 20–35 minutes (Cloud SQL creation dominates).

3. When it completes, discover the resources with name-agnostic filters (so the commands keep working regardless of the deployment suffix):

   SERVICE=$(gcloud run services list --project="$PROJECT" --region="$REGION" \
     --filter="metadata.name~shlink" --format="value(metadata.name)" --limit=1)
   SERVICE_URL=$(gcloud run services describe "$SERVICE" \
     --project="$PROJECT" --region="$REGION" --format="value(status.url)")
   echo "Service: $SERVICE"
   echo "URL:     $SERVICE_URL"

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Task 2 — Access & verify [Manual]

1. Confirm the service is healthy. Shlink's health path is /rest/health — an unauthenticated endpoint returning HTTP 200 with {"status":"pass",...}. Do not test / — Shlink is API-first and has no homepage, so the root path returns 404 by design. With scale-to-zero, allow ~5–15 seconds for the first request to cold-start an instance:

   curl -s "$SERVICE_URL/rest/health"
   # {"status":"pass","version":"...","links":{...}}

2. Retrieve the auto-generated API key from Secret Manager and create your first short URL through the REST API:

   API_SECRET=$(gcloud secrets list --project="$PROJECT" \
     --filter="name~shlink AND name~initial-api-key" --format="value(name)" --limit=1)
   API_KEY=$(gcloud secrets versions access latest --secret="$API_SECRET" --project="$PROJECT")
   
   curl -s -X POST "$SERVICE_URL/rest/v3/short-urls" \
     -H "X-Api-Key: $API_KEY" -H "Content-Type: application/json" \
     -d '{"longUrl": "https://cloud.google.com/run"}'

   Follow the returned shortUrl in a browser (or curl -I) and confirm the redirect; then list recorded visits:

   curl -s "$SERVICE_URL/rest/v3/short-urls" -H "X-Api-Key: $API_KEY"

3. Post-deploy hardening/setup: set DEFAULT_DOMAIN (via the environment_variables input and the Update flow) to the service's public hostname so generated short URLs carry the right host, and optionally add a GEOLITE_LICENSE_KEY to enable visit geolocation. For a browser UI, point the hosted shlink-web-client at $SERVICE_URL with your API key.

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Task 3 — Operate & keep it running (Day-2) [Manual]

1. Inspect the service and its revisions (each deploy creates an immutable revision; traffic shifts to the newest healthy one):

   gcloud run services describe "$SERVICE" --project="$PROJECT" --region="$REGION"
   gcloud run revisions list --service="$SERVICE" --project="$PROJECT" --region="$REGION"

2. Scale by changing the min/max instance inputs and clicking Update on the deployment details page — the module owns the service spec, so scaling is a configuration change, not a manual gcloud edit (a manual edit would be reverted on the next apply). The default is scale-to-zero (min = 0); set min = 1 to eliminate the cold start on the first redirect after idle. Before raising max_instance_count well beyond 3, enable Redis for shared caching/locking.

3. Update the application version by changing the version input via Update on the deployment details page; a new image builds and a new revision rolls out. Shlink runs its schema migrations automatically on the new revision's first start.

4. Manage secrets, storage, and jobs:

   gcloud secrets list --project="$PROJECT" --filter="name~shlink"
   gcloud run jobs list --project="$PROJECT" --region="$REGION"   # db-init + backup jobs

5. Open a database session for inspection or maintenance (the tenant-scoped database user is in the deployment outputs):

   INSTANCE=$(gcloud sql instances list --project="$PROJECT" --format="value(name)" --limit=1)
   gcloud sql connect "$INSTANCE" --user=postgres --project="$PROJECT"

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Task 4 — Observe: Logging & Monitoring [Manual]

1. Logs — from the CLI or the Logs Explorer:

   gcloud run services logs read "$SERVICE" --project="$PROJECT" --region="$REGION" --limit=50

   Logs Explorer filter: resource.type="cloud_run_revision" AND resource.labels.service_name="<service>".

2. Monitoring — open the Cloud Run dashboard for the service and review request count, request latency (P50/P95/P99 — the metric that matters most for a redirect service), instance count (watch scale-to-zero in action between requests), and CPU / memory utilisation. The module also provisions an uptime check against /rest/health; confirm it is green under Monitoring → Uptime checks, and review Alerting → Policies.

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Task 5 — Troubleshoot & debug [Manual]

Durable techniques for the failure modes you are most likely to hit. These are platform-level diagnostics and do not change with Shlink releases.

• / returns 404: not a failure — Shlink has no web homepage. Verify health at /rest/health and interact via /rest/v3/... with the X-Api-Key header.
• Revision unhealthy / service won't serve: the startup probe allows up to ~300 seconds for first-boot database migrations. Inspect the latest revision and its logs before concluding the service has failed:

  gcloud run revisions list --service="$SERVICE" --project="$PROJECT" --region="$REGION"
  gcloud run services logs read "$SERVICE" --project="$PROJECT" --region="$REGION" --limit=100

• Database connection errors: confirm the Cloud SQL (PostgreSQL 15) instance is RUNNABLE, the DB password secret exists, and the db-init job completed. Never set DB_USER/DB_NAME manually in environment_variables — the foundation injects tenant-scoped values, and overriding them causes password authentication failed.
• Initialisation job failed: list executions and read the failed one's logs:

  gcloud run jobs executions list --job="${SERVICE}-db-init" \
    --project="$PROJECT" --region="$REGION"

• 401 on API calls: the X-Api-Key header must carry the value of the initial-api-key secret (or a key you created with it). Re-fetch it from Secret Manager as in Task 2.
• Wrong host in generated short URLs: set DEFAULT_DOMAIN to the public hostname (see Task 2 step 3) — until then Shlink may build short URLs against the wrong domain.
• Image build failed: review Cloud Build history for the failed build's log; the image is a thin wrapper built from shlinkio/shlink:stable and mirrored into Artifact Registry.
• 403 / permission errors: verify the runtime service account's IAM roles.

See the Configuration Guide's Configuration Pitfalls section for setting-specific gotchas.

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Task 6 — Tear down [Automated]

On the Deployments page, open the deployment and click the Trash icon (Delete). Delete runs terraform destroy and is irreversible (the deployment record is retained for history). If a deployment is stuck and the RAD platform can no longer manage it (for example after manual changes that conflict with the Terraform state), use Purge instead — it removes the deployment from RAD's records without destroying the cloud resources (it makes RAD forget the project). This removes everything the module created — the Cloud Run service, Cloud SQL database, Secret Manager secrets (including the initial API key), and Artifact Registry images. Resources owned by Services_GCP (the VPC, shared Cloud SQL, registry) are managed separately and are not removed here.

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Summary

Task	Type	Outcome
1 — Deploy	Automated	Module provisions Cloud Run, Cloud SQL (PostgreSQL 15), secrets, and runs DB init
2 — Access & verify	Manual	/rest/health passes; first short URL created via the REST API with the bootstrap key
3 — Operate	Manual	Inspect revisions, scale, update version, manage secrets/backups, DB access
4 — Observe	Manual	Query Cloud Logging; review Cloud Monitoring metrics and uptime check
5 — Troubleshoot	Manual	Diagnose revision, database, init-job, API-key, build, and IAM issues
6 — Tear down	Automated	Delete (Trash) removes all module resources