# Cloud GCP > Use this skill when architecting on Google Cloud Platform, selecting GCP services, or implementing data and compute solutions. Triggers on Cloud Run, BigQuery, Pub/Sub, GKE, Cloud Functions, Cloud Storage, Firestore, Spanner, Cloud SQL, IAM, VPC, and any task requiring GCP architecture decisions or service selection. - Skill: `majiayu000/cloud-gcp` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds add majiayu000/cloud-gcp` - Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/cloud-gcp/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: DevOps & Infra - License: MIT - Author: majiayu000 (https://skillmd.com/u/majiayu000) - Updated: 2026-09-09 - Page: https://skillmd.com/skills/majiayu000/cloud-gcp --- When this skill is activated, always start your first response with the ๐Ÿงข emoji. # Google Cloud Platform GCP is Google's suite of cloud infrastructure and managed services. This skill covers architecture decisions, service selection, and implementation patterns for the most commonly used GCP building blocks: compute (Cloud Run, GKE, Cloud Functions), data (BigQuery, Cloud Storage, Pub/Sub), and databases (Cloud SQL, Firestore, Spanner, Bigtable). The emphasis is on *choosing the right service* for the problem and *configuring it correctly* rather than memorizing every API surface. --- ## When to use this skill Trigger this skill when the user: - Deploys a containerized service or API to GCP - Designs a data pipeline (ingestion, transformation, analytics) - Needs to choose between GCP database offerings (Cloud SQL, Firestore, Spanner, Bigtable) - Sets up IAM roles, service accounts, or Workload Identity - Architects an event-driven system with Pub/Sub and Cloud Functions - Configures networking (VPC, Load Balancer, Cloud CDN, Cloud Armor) - Estimates or controls GCP costs (BigQuery slot reservations, Cloud Run concurrency) Do NOT trigger this skill for: - AWS or Azure architecture (use the corresponding cloud skill) - Application-level code that happens to run on GCP but has no GCP-specific concerns --- ## Key principles 1. **Managed services first** - Prefer fully managed services (Cloud Run, BigQuery, Firestore) over self-managed ones (GCE with custom installs). The operational overhead of managing VMs, patches, and scaling is rarely worth the flexibility. 2. **BigQuery is the analytics layer** - BigQuery is GCP's default for any analytical workload at any scale. It is serverless, cost-effective for infrequent queries, and integrates with Dataflow, Pub/Sub, and Looker. Use it unless you need sub-second OLTP latency. 3. **Cloud Run is the default compute** - For HTTP-serving workloads, Cloud Run (not GKE, not App Engine) is the right default. It is stateless, auto-scales to zero, and charges per request-second. Move to GKE only when you need persistent connections, GPUs, or complex networking. 4. **Pub/Sub for decoupling** - Whenever two services need to communicate asynchronously, route through Pub/Sub. It provides durable delivery, at-least-once semantics, replay, and dead-letter queues without you managing a broker. 5. **IAM at project level, fine-grained at resource level** - Grant roles at the lowest resource scope possible. Use service accounts with Workload Identity for workloads running on GCP - never create and download service account key files. --- ## Core concepts ### Resource hierarchy ``` Organization โ””โ”€โ”€ Folders (teams, environments) โ””โ”€โ”€ Projects <-- primary billing and IAM boundary โ””โ”€โ”€ Resources (Cloud Run services, BigQuery datasets, buckets, etc.) ``` IAM policies are inherited downward. A role granted at the organization level applies to all projects. Grant permissions at the project or resource level to limit blast radius. ### IAM model Every GCP principal (user, service account, group) is granted **roles**, which are bundles of **permissions**. There are three role types: | Type | Example | When to use | |---|---|---| | Basic | `roles/viewer`, `roles/editor` | Never in production - too broad | | Predefined | `roles/run.invoker`, `roles/bigquery.dataViewer` | Default choice | | Custom | Built from individual permissions | When predefined is still too broad | Service accounts are identities for workloads. Use Workload Identity to bind a Kubernetes service account to a GCP service account - no key files needed. ### Compute spectrum | Service | Trigger | State | Scale to zero | Use case | |---|---|---|---|---| | Cloud Functions (gen2) | Event / HTTP | Stateless | Yes | Lightweight event handlers | | Cloud Run | HTTP / gRPC | Stateless | Yes | Containerized APIs, backends | | GKE Autopilot | Always-on | Stateful OK | No | Long-running, GPU, complex networking | | Compute Engine | Always-on | Stateful | No | VMs, custom OS, legacy lift-and-shift | ### Storage and database tiers | Service | Model | Sweet spot | |---|---|---| | Cloud Storage | Object / blob | Files, backups, data lake raw zone | | BigQuery | Columnar OLAP | Analytics, reporting, ad-hoc queries | | Cloud SQL | Relational (Postgres/MySQL) | OLTP, existing SQL apps | | Firestore | Document (NoSQL) | Mobile/web, hierarchical, real-time sync | | Spanner | Globally distributed relational | Finance, inventory, global consistency | | Bigtable | Wide-column NoSQL | Time-series, IoT, >1 TB key-value | | Memorystore | Redis / Memcached | Caching, session storage, leaderboards | --- ## Common tasks ### Deploy a containerized service to Cloud Run ```bash # Build and push image to Artifact Registry gcloud builds submit --tag us-central1-docker.pkg.dev/PROJECT/REPO/my-service:latest # Deploy with recommended production settings gcloud run deploy my-service \ --image us-central1-docker.pkg.dev/PROJECT/REPO/my-service:latest \ --region us-central1 \ --platform managed \ --service-account my-service-sa@PROJECT.iam.gserviceaccount.com \ --set-env-vars "ENV=production" \ --memory 512Mi \ --cpu 1 \ --concurrency 80 \ --max-instances 10 \ --no-allow-unauthenticated # use --allow-unauthenticated for public APIs ``` Key dials: - `--concurrency` - requests handled per container instance (default 80). Lower it for CPU-bound work; increase for I/O-bound. - `--max-instances` - hard cap to control costs and protect downstream services. - `--no-allow-unauthenticated` + `roles/run.invoker` on the calling service account is the correct pattern for service-to-service calls. ### Design a data pipeline Standard GCP data pipeline pattern: ``` Source (app events, CDC, files) --> Pub/Sub topic (ingestion buffer, durability) --> Dataflow job (transform, enrich, validate) --> BigQuery dataset (analytics layer) --> Looker / Looker Studio (visualization) ``` For simpler pipelines without transformation logic, use **BigQuery subscriptions** directly from Pub/Sub (no Dataflow needed). For batch ingestion from Cloud Storage, use **BigQuery Data Transfer Service** or a scheduled Dataflow pipeline. ### Set up BigQuery for analytics ```sql -- Create a dataset with a region and expiration CREATE SCHEMA my_project.analytics OPTIONS ( location = 'us-central1', default_table_expiration_days = 365 ); -- Partition tables by date to control scan costs CREATE TABLE analytics.events ( event_id STRING, user_id STRING, event_ts TIMESTAMP, payload JSON ) PARTITION BY DATE(event_ts) CLUSTER BY user_id; -- Use partition filters to avoid full-table scans SELECT user_id, COUNT(*) as cnt FROM analytics.events WHERE DATE(event_ts) BETWEEN '2024-01-01' AND '2024-03-31' GROUP BY user_id; ``` Cost control checklist: - Always partition large tables by date/timestamp - Cluster on high-cardinality filter columns (user_id, org_id) - Use `SELECT specific_columns` not `SELECT *` - Set column-level access policies on PII fields - Monitor with `INFORMATION_SCHEMA.JOBS` to catch expensive queries ### Choose the right database Use this decision matrix: ``` Do you need SQL? YES -> Is global multi-region consistency required? YES -> Spanner NO -> Cloud SQL (Postgres preferred) NO -> Is data hierarchical / document-shaped? YES -> Is real-time sync or offline support needed? YES -> Firestore NO -> Firestore (still fine) or BigQuery for analytics NO -> Is it time-series / IoT at >1 TB scale? YES -> Bigtable NO -> Cloud Storage (data lake) or BigQuery ``` Key differentiators: - **Cloud SQL** caps at ~10 TB and one primary region - fine for most apps - **Spanner** is 5-10x the cost of Cloud SQL; justify with global write requirements - **Firestore** bills per operation, not compute - avoid heavy aggregation queries - **Bigtable** has a minimum cost (~$0.65/hr per node); not worth it under 1 TB ### Configure IAM with least privilege ```bash # Create a service account for a Cloud Run service gcloud iam service-accounts create my-service-sa \ --display-name "my-service runtime SA" # Grant only the permissions it needs gcloud projects add-iam-policy-binding PROJECT \ --member "serviceAccount:my-service-sa@PROJECT.iam.gserviceaccount.com" \ --role "roles/bigquery.dataViewer" gcloud projects add-iam-policy-binding PROJECT \ --member "serviceAccount:my-service-sa@PROJECT.iam.gserviceaccount.com" \ --role "roles/pubsub.publisher" # For GKE: bind Kubernetes SA to GCP SA via Workload Identity gcloud iam service-accounts add-iam-policy-binding my-service-sa@PROJECT.iam.gserviceaccount.com \ --role "roles/iam.workloadIdentityUser" \ --member "serviceAccount:PROJECT.svc.id.goog[NAMESPACE/KSA_NAME]" ``` > Never create and download service account key JSON files for workloads running on > GCP. Use Workload Identity for GKE, and the automatic metadata server for Cloud Run. > Key files leak, expire, and are a primary source of GCP credential breaches. ### Set up Cloud CDN and Load Balancer For a Cloud Run service that needs CDN caching: ```bash # Create a serverless NEG pointing at Cloud Run gcloud compute network-endpoint-groups create my-service-neg \ --region us-central1 \ --network-endpoint-type serverless \ --cloud-run-service my-service # Create backend service and enable CDN gcloud compute backend-services create my-service-backend \ --global \ --enable-cdn \ --cache-mode CACHE_ALL_STATIC \ --custom-response-header "Cache-Control:public, max-age=3600" gcloud compute backend-services add-backend my-service-backend \ --global \ --network-endpoint-group my-service-neg \ --network-endpoint-group-region us-central1 # Create URL map, target proxy, and forwarding rule # (typically done via Terraform for production) ``` Use Cloud Armor on the backend service to add WAF rules and rate limiting at the edge. Attach Cloud CDN only to responses that are safe to cache - set `Cache-Control: private` on auth-gated endpoints. ### Implement event-driven architecture with Pub/Sub and Cloud Functions ```bash # Create a topic gcloud pubsub topics create order-created # Create a dead-letter topic for failed messages gcloud pubsub topics create order-created-dlq # Create a push subscription that triggers Cloud Functions (gen2) gcloud pubsub subscriptions create order-created-sub \ --topic order-created \ --ack-deadline 60 \ --dead-letter-topic order-created-dlq \ --max-delivery-attempts 5 # Deploy a Cloud Function triggered by the topic gcloud functions deploy process-order \ --gen2 \ --runtime nodejs20 \ --trigger-topic order-created \ --region us-central1 \ --service-account processor-sa@PROJECT.iam.gserviceaccount.com \ --set-env-vars "PROJECT_ID=PROJECT" ``` Pattern notes: - Always configure a dead-letter topic - without one, a poison-pill message retries indefinitely and blocks the subscription. - Set `--ack-deadline` to at least 2x your function's expected execution time. - Use `--max-delivery-attempts 5` with exponential backoff before DLQ. - For high-throughput scenarios (>10k msg/s), use **Dataflow** instead of Functions. --- ## Anti-patterns / common mistakes | Mistake | Why it's wrong | What to do instead | |---|---|---| | Downloading service account key files | Credentials that leak, don't auto-rotate, and are hard to audit | Use Workload Identity (GKE) or the metadata server (Cloud Run) | | `SELECT *` on large BigQuery tables | Scans entire table regardless of filters, costs multiply | Select only needed columns; partition + cluster the table | | No dead-letter topic on Pub/Sub subscriptions | Poison-pill messages block the subscription indefinitely | Always configure a DLQ with `--max-delivery-attempts` | | Spanner for a single-region OLTP app | 5-10x the cost of Cloud SQL with no benefit | Use Cloud SQL (Postgres) unless global writes are required | | Granting `roles/editor` to a service account | Overly broad; can read/write all project resources | Grant narrowest predefined role needed; use custom roles if required | | Cloud Run without max-instances | Unexpected traffic spike can exhaust downstream DB connections | Always set `--max-instances` and size connection pools accordingly | --- ## Gotchas 1. **Cloud Run without max-instances is a database killer** - Cloud Run scales to hundreds of instances on traffic spikes. Each instance holds its own connection pool. Without `--max-instances`, a traffic spike can open thousands of database connections and exhaust Cloud SQL or Spanner limits. Always set `--max-instances` and size `--concurrency` to match your downstream connection budget. 2. **BigQuery charges for scanned bytes, not returned rows** - A `SELECT *` on a 10 TB table bills for 10 TB even if you filter to one row. Always select only the columns needed and add partition filter clauses. Without a `WHERE DATE(event_ts) BETWEEN ...` condition on a partitioned table, the query scans all partitions. 3. **Pub/Sub without a dead-letter topic blocks the subscription** - A single malformed message that causes the consumer to throw an exception will be retried indefinitely (up to `--max-delivery-attempts`, but that defaults to unlimited without a DLQ configured). Always set `--dead-letter-topic` and `--max-delivery-attempts` together - one without the other provides incomplete protection. 4. **Service account key files are a persistent credential leak vector** - Downloaded JSON key files don't expire, are easy to commit to git, and can't be audited as precisely as Workload Identity. GCP's metadata server and Workload Identity provide automatic, rotating credentials for every compute surface. Never create key files for workloads that run on GCP infrastructure. 5. **Firestore billing on aggregation queries** - Firestore bills per document read. A query that counts documents in a collection reads every document to compute the count. At scale, this means `SELECT COUNT(*)` equivalents are extremely expensive. Maintain aggregation counters as separate documents and update them via Cloud Functions triggered on writes. --- ## References For detailed patterns and reference tables on specific GCP topics, read the relevant file from the `references/` folder: - `references/service-map.md` - quick lookup of use case to GCP service Only load a references file if the current task requires it - they add context length. --- ## Companion check > On first activation of this skill in a conversation: check which companion skills are installed by running `ls ~/.claude/skills/ ~/.agent/skills/ ~/.agents/skills/ .claude/skills/ .agent/skills/ .agents/skills/ 2>/dev/null`. Compare the results against the `recommended_skills` field in this file's frontmatter. For any that are missing, mention them once and offer to install: > ``` > npx skills add AbsolutelySkilled/AbsolutelySkilled --skill > ``` > Skip entirely if `recommended_skills` is empty or all companions are already installed.