Troubleshooting

Troubleshooting

Port 8080 in Use

lsof -ti:8080 | xargs kill -9
# or
pkill -f "flight-path/server"

API Returns 404

• Health check is GET / (not /health)
• Calculate is POST /calculate (not GET)
• Check Swagger: http://localhost:8080/swagger/index.html

API Returns 500

• Check server terminal for error logs
• Test with minimal input: curl -X POST http://localhost:8080/calculate -H 'Content-Type: application/json' -d '[["SFO", "EWR"]]'
• Verify input format: [][]string — each segment must be exactly 2 airport codes

Swagger Docs Stale

make api-docs    # Regenerate from annotations
pkill -f server  # Restart server
make run

• If generation fails, check Swagger annotation syntax against existing handlers in internal/handlers/
• Hard-refresh browser (Ctrl+Shift+R) to clear cached Swagger UI

Build Fails

go version                # Must match the `go` directive in go.mod
go mod tidy && make build # Clean up and retry
go clean -cache           # Nuclear option

• make build depends on api-docs (which depends on deps), then compiles
• Ensure GOFLAGS=-mod=mod is set (Makefile sets this automatically)
• Use make check (alias for make ci) for the full local pipeline: static-check + test + integration-test + coverage + coverage-check + build + fuzz + deps-prune-check

static-check / govulncheck Fails on an Unrelated PR (Go stdlib CVE)

Symptom: An open PR that touches no Go code — e.g. a Renovate GitHub Actions SHA bump — fails the static-check job at the govulncheck step. Multiple in-flight PRs fail identically.

Root cause: govulncheck flags a Go standard-library vulnerability present in the pinned Go patch on main. The failure lives in main's toolchain, not the PR diff, so it surfaces on every PR's static-check. This is the "N in-flight PRs failing identically → diagnose main, not the PRs" pattern. It recurs each time a Go patch ships stdlib security fixes.

Diagnose — read the actual failing step, don't guess:

gh run view  --log-failed | grep -A4 'Vulnerability #'
# Look for: "Standard library", "Found in: @goX.Y.Z", "Fixed in: @goX.Y.W"

Fix (real fix — bump Go; NEVER waive a reachable stdlib CVE). Bump the Go patch across all three pins in ONE change (mirrors Renovate's "Go toolchain" group so the managers stay consistent):

| File | Line | |------|------| | go.mod | go X.Y.W | | .mise.toml | go = "X.Y.W" | | Dockerfile | golang:1.26-alpine@sha256: — refresh so the docker job's Trivy scan doesn't ship a binary built against the old stdlib |

Get the new digest and confirm it is the fixed patch before editing:

docker buildx imagetools inspect golang:1.26-alpine --format '{{.Manifest.Digest}}'
docker run --rm golang:1.26-alpine@ go version   # MUST show the fixed patch goX.Y.W

Verify locally before pushing (this is the proof, not a hope):

mise install go@X.Y.W
mise exec -- govulncheck ./...   # must report "No vulnerabilities found"
make static-check                # the full gate that was failing
make check-go-alignment          # go.mod and .mise.toml must agree

The bump is not done at the pins — sweep the docs in the SAME PR. Prose docs (README.md, CLAUDE.md, specs/, docs/ARCHITECTURE.md, the .claude/agents/*.md and .claude/skills/*.md files) are not touched by Renovate and go stale on merge. Do NOT grep one exact version string — grep the broad pattern across the whole tree and prove zero stale remain:

git ls-files | xargs grep -nE 'go ?1\.26|gvm' 2>/dev/null   # inspect every hit
make check-docs-go-version                                   # the drift gate; must pass

check-docs-go-version runs inside static-check and reds CI if any live-state doc still shows an old Go patch — never declare the bump done until it is green. Full procedure: the "Bumping the Go version" checklist in the workflows skill.

Then PR the fix to main (do NOT push onto the Renovate branch — it can auto-merge from under you). Renovate auto-rebases the in-flight PRs onto the fix and they go green.

Why Renovate didn't bump it first: Go patches ship ~monthly and govulncheck flips red the instant a CVE is disclosed — faster than any Renovate schedule + CI + automerge cycle, so a manual bump-on-red is the correct fast path. Additionally, if past Go bumps were applied manually (as stdlib-CVE fires force), Renovate's gomod extraction diverges and the "Go toolchain" group stops firing. Tell: the Renovate Dependency Dashboard (issue #8) freezes at an old go version and lists deps the repo no longer has. To re-engage it, tick the rebase/refresh checkbox on the Dashboard to force a fresh extraction.

Tests Fail

go test -v ./...          # Verbose output
go clean -testcache       # Clear cache
go test -race ./...       # Check for races

• make test runs tests with TZ="UTC" and GOFLAGS=-mod=mod
• Benchmarks: go test ./internal/handlers/ -bench=. -benchmem -benchtime=3s

E2E Tests Fail

Server must be running first:

make run &
sleep 3
make e2e
pkill -f server

• make e2e depends on deps (installs Newman if missing)
• Tests live in test/FlightPath.postman_collection.json
• CI polls with curl for up to 30 seconds for server startup

Docker Build Fails

docker buildx ls                    # Check builder exists
docker buildx create --use --name builder --driver docker-container --bootstrap
make image-build                    # Build locally (single platform, uses buildx)
docker build --no-cache -t flight-path:debug .  # Build without cache

• Image: multi-stage Alpine build (golang:1.26-alpine -> alpine:3.23.4)
• Non-root user: srvuser:srvgroup (uid/gid 1000)
• CGO_ENABLED=0, platforms: linux/amd64, linux/arm64, linux/arm/v7
• make image-push builds then pushes to GHCR (ghcr.io//flight-path:); requires GH_ACCESS_TOKEN. Multi-arch build + cosign signing happen in the docker CI job on tag pushes

Docker Container: Port Configuration

The container runs fine without a .env file. internal/envfile.Load treats a missing file as a no-op (returns nil), and app.Port() defaults to 8080 when SERVER_PORT is unset — so there is no "crashes without .env" issue (the in-house envfile package replaced github.com/joho/godotenv, which used to log.Fatal on a missing file).

To run on a non-default port, set SERVER_PORT via -e (or an env-file):

docker run -d -p 9090:9090 -e SERVER_PORT=9090 flight-path:local

make image-run / make image-test handle this automatically — they bind a free host port and pass --env-file .env.example.

Tool Not Found

make deps                           # Install all tools
export PATH=$PATH:$(go env GOPATH)/bin  # Ensure tools are on PATH

• newman requires Node.js — make deps provisions Node via mise and installs newman via pnpm (corepack)

Diagnostic Commands

ps aux | grep -E "(server|flight-path)"  # Check processes
lsof -i:8080                              # Check port
curl http://localhost:8080/                # Test health
which swag golangci-lint gosec govulncheck gitleaks actionlint newman  # Check tools
go env GOPATH GOROOT                       # Check Go paths
make check                                # Run full pre-commit checklist

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: AndriyKalashnykov
• Source: AndriyKalashnykov/flight-path
• License: MIT

Install and usage instructions live in the source repository linked above.