fodinfo

fodinfo is a tiny web application made with Go F# that showcases best practices of running microservices in Kubernetes. fodinfo is a F# port of the great work of @stefanprodan in https://github.com/stefanprodan/podinfo to F#.

Why?

Im using this as a project to learn F# and potentially create a usefull template for F# project.

Stack

• Falco

Specifications:

• [x] Health checks (readiness and liveness)
• [ ] Instrumented with Prometheus (In Progress)
• [ ] 12-factor app (In Progress)
• [ ] File watcher for secrets and configmaps
• [ ] Tracing with Istio and Jaeger
• [ ] Linkerd service profile
• [x] Structured logging
• [ ] Fault injection (random errors and latency)
• [ ] Swagger docs
• [ ] Helm and Kustomize installers
• [ ] End-to-End testing with Kubernetes Kind and Helm
• [ ] Kustomize testing with GitHub Actions and Open Policy Agent
• [ ] Multi-arch container image with Docker buildx and Github Actions
• [ ] CVE scanning with trivy
• [ ] Graceful shutdown on interrupt signals

Web API:

• [ ] GET / prints runtime information
• [x] GET /version prints fodinfo version and git commit hash
• [x] GET /metrics return HTTP requests duration and Go runtime metrics
• [x] GET /healthz used by Kubernetes liveness probe
• [x] GET /readyz used by Kubernetes readiness probe
• [x] POST /readyz/enable signals the Kubernetes LB that this instance is ready to receive traffic
• [x] POST /readyz/disable signals the Kubernetes LB to stop sending requests to this instance
• [x] GET /status/{code} returns the status code
• [x] GET /panic crashes the process with exit code 255
• [x] POST /echo forwards the call to the backend service and echos the posted content
• [x] GET /env returns the environment variables as a JSON array
• [x] GET /headers returns a JSON with the request HTTP headers
• [x] GET /delay/{seconds} waits for the specified period
• [ ] POST /token issues a JWT token valid for one minute JWT=$(curl -sd 'anon' fodinfo:5000/token | jq -r .token)
• [ ] GET /token/validate validates the JWT token curl -H "Authorization: Bearer $JWT" fodinfo:5000/token/validate
• [ ] GET /configs returns a JSON with configmaps and/or secrets mounted in the config volume
• [ ] POST/PUT /cache/{key} saves the posted content to Redis
• [ ] GET /cache/{key} returns the content from Redis if the key exists
• [ ] DELETE /cache/{key} deletes the key from Redis if exists
• [x] POST /store writes the posted content to disk at /data/hash and returns the SHA1 hash of the content
• [x] GET /store/{hash} returns the content of the file /data/hash if exists
• [ ] GET /ws/echo echos content via websockets podcli ws ws://localhost:5000/ws/echo
• [ ] GET /chunked/{seconds} uses transfer-encoding type chunked to give a partial response and then waits for the specified period
• [ ] GET /swagger.json returns the API Swagger docs, used for Linkerd service profiling and Gloo routes discovery