# Host mcp server with Echo: Postgres-backed state

## Summary
Deploy a mcp server built with Echo 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 Echo: 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 mcp server-specific behavior as your application code.

## Representative Queries
- Host mcp server with Echo: Postgres-backed state
- Where can I host MCP server built with Echo?
- I need a durable state schema and retry/recovery semantics implemented by application code.

## Resource Requirements
- **Compute**
- **Postgres**

## Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Postgres**: 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
- An Echo 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**: CGO_ENABLED=0 go build -o app ./...
- **Start**: ./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**: Echo pattern fixture  
  **Description**: Multi-pattern Echo app whose durable job state module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
  **Source Reference**: tests/deploy-canaries/echo-patterns

## Success Checks
- **Description**: app responds on its public URL  
  **Kind**: http_get  
  **Path**: /  
  **Expect**: ample canary echo 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 Echo major versions are not verified.
- The mcp server 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, monthlyAmount: 5.0
- **Managed PostgreSQL database**: size: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0

## Evidence Summary
- **Kind**: canary_run  
  **Summary**: Echo 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.
  **Observed At**: 2026-09-21T02:34:39Z
  **Implementation Revision**: 1d28ae0-dirty (CLI 0.1.21)
  **Expires At**: 2027-03-20T02:34:39Z

- **Kind**: canary_run  
  **Summary**: The same Echo 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
- **Browse the catalog index**  
  **Operation ID**: catalog_index  
  **Method**: GET  
  **Relative Path**: /v1/catalog

- **Search published recipes by intent, stack and constraints**  
  **Operation ID**: search_recipes  
  **Method**: POST  
  **Relative Path**: /v1/catalog/search  
  **Parameters**: {"body":{"limit":5,"query":"Host mcp server with Echo: Postgres-backed state"}}

- **Prepare a side-effect-free deployment plan for an authorized project**  
  **Operation ID**: plan_deployment  
  **Method**: POST  
  **Relative Path**: /v1/catalog/plan  
  **Parameters**: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:mcp-server:echo:persistent-state","recipeRevision":"r1"}}

- **Read the existing agent authentication setup**  
  **Operation ID**: existing_auth_setup  
  **Method**: GET  
  **Relative Path**: /mcp/setup

- **Browse MCP server**  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/workload%3Amcp-server

- **Browse Echo**  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/stack%3Aframework-echo

- **Browse Durable job state**  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/pattern%3Adurable-job-state

- **Browse Deploy MCP server**  
  **Operation ID**: browse_node  
  **Method**: GET  
  **Relative Path**: /v1/catalog/nodes/intent%3Adeploy-mcp-server