page:recipes:mobile backend:gin:persistent state

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