page:recipes:reporting dashboard:flask:attachments

Host reporting dashboard with Flask: file attachments

Summary: Deploy a reporting dashboard built with Flask on Ample using the browser file uploads 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, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Flask: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the reporting dashboard-specific behavior as your application code.

Framework: Flask

Workload: Reporting dashboard

Release Status: published

Support Status: verified

Execution Status: ready

Prerequisites:

Workflow Steps

  1. Build and start: pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template. The server must bind 0.0.0.0 on PORT.
  2. Implement the pattern on PostgreSQL: The fixture's module implements browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
  3. Wire object storage: Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
  4. 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.
  5. Verify: Fetch the live URL and the pattern self-test route(s) (/p/browser-file-uploads) from the example; then run your own checks. On failure read ample logs --kind build then --kind runtime.

Input Schema

{
  "type": "object",
  "properties": {
    "env": {
      "description": "Encrypted environment variables (bucket credentials, secrets)",
      "type": "array",
      "items": {
        "pattern": "^[A-Z][A-Z0-9_]*=.*$",
        "type": "string"
      },
      "maxItems": 50
    },
    "name": {
      "description": "App name",
      "type": "string",
      "minLength": 1,
      "maxLength": 63,
      "pattern": "^[a-z0-9-]+$"
    },
    "path": {
      "description": "Project directory or ample.toml service",
      "type": "string",
      "minLength": 1,
      "maxLength": 512
    },
    "release_command": {
      "description": "Migration command run before activation",
      "type": "string",
      "maxLength": 512
    },
    "start": {
      "description": "Start command (Python apps pass one explicitly)",
      "type": "string",
      "maxLength": 512
    }
  },
  "required": ["env", "name", "path", "start"],
  "additionalProperties": false
}

Cost Estimate

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.

Limitations

Evidence Summary

Examples