## Host mobile backend with Gin: Postgres-backed state

Deploy a mobile backend built with Gin on Ample using the durable job state pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Gin: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the mobile backend-specific behavior as your application code.

### Representative Queries
- Host mobile backend with Gin: Postgres-backed state
- Where can I host Mobile backend built with Gin?
- I need a durable state schema and retry/recovery semantics implemented by application code.

### Resource Requirements
- Compute
- Postgres

### Infrastructure Requirements
#### Compute
- **Status**: Verified  
- **Summary**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

#### Postgres
- **Status**: Verified  
- **Summary**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

### Prerequisites
- A Gin project that builds and starts with the documented commands (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build))  
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)  
- An Ample account token with servers:write, databases:read

### Tested Configuration  
- **Template**: ubuntu-24.04  
- **Runtime**: go  
- **Size**: s-1vcpu-1gb  
- **Build Command**: CGO_ENABLED=0 go build -o app ./...  
- **Start Command**: ./app

### Workflow Steps  
1. **Build and start**  
   CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build). The server must bind 0.0.0.0 on PORT.  
2. **Implement the pattern on PostgreSQL**  
   The fixture's module implements durable job state: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.  
3. **Deploy**  
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.  
   **Command**: ample deploy . --name  --public  
4. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/durable-job-state) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.  
   **Command**: ample logs  --kind build

### Examples  
- **Title**: Gin pattern fixture  
  **Description**: Multi-pattern Gin app whose durable job state module was checked live; the module is under tests/deploy-canaries/_pattern-modules.  
- **Source Reference**: tests/deploy-canaries/gin-patterns

### Success Checks
- **Description**: app responds on its public URL  
  **Kind**: http_get  
  **Path**: /  
  **Expect**: ample canary gin patterns  
- **Description**: durable-job-state self-test  
  **Kind**: http_get  
  **Path**: /p/durable-job-state  
  **Expect**: job=done attempts=1 idempotent=true

### Limitations  
- Verified on the ubuntu-24.04 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Gin major versions are not verified.
- The mobile backend itself (your job types, payload schema and retry policy) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

### Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: 10.0  
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.
  
#### Components  
- **App Server**  
  - Size: s-1vcpu-1gb  
  - Quantity: 1.0  
  - Monthly Amount: 5.0  
- **Managed PostgreSQL Database**  
  - Size: s-1vcpu-1gb  
  - Quantity: 1.0  
  - Monthly Amount: 5.0

### Evidence Summary  
1. **Kind**: canary_run  
   **Summary**: Gin pattern fixture deployed on Ample (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build)); checks passed for durable-job-state and configuration-secrets. Pattern proof: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true).
   **Observed At**: 2026-09-21T01:15:54Z  
   **Implementation Revision**: 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)
   **Expires At**: 2027-03-20T01:15:54Z

2. **Kind**: canary_run  
   **Summary**: The same Gin app deployed with a --release-command migration; the marker it created was readable after activation.
   **Observed At**: 2026-09-20T02:43:30Z  
   **Implementation Revision**: 199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI b75e104)  
   **Expires At**: 2027-03-19T02:43:30Z

### Next Actions
- **Action**: Browse the catalog index  
  **Operation ID**: catalog_index  
  **Method**: GET  
  **Relative Path**: /v1/catalog
- **Action**: Search published recipes by intent, stack and constraints  
  **Operation ID**: search_recipes  
  **Method**: POST  
  **Relative Path**: /v1/catalog/search  
- **Action**: Prepare a side-effect-free deployment plan for an authorized project  
  **Operation ID**: plan_deployment  
  **Method**: POST  
  **Relative Path**: /v1/catalog/plan  
- **Action**: Read the existing agent authentication setup  
  **Operation ID**: existing_auth_setup  
  **Method**: GET  
  **Relative Path**: /mcp/setup  
- **Action**: Browse Mobile backend  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/workload%3Amobile-backend
- **Action**: Browse Gin  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/stack%3Aframework-gin
- **Action**: Browse Durable job state  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/pattern%3Adurable-job-state
- **Action**: Browse Deploy API  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/intent%3Adeploy-api