Go backend for location tracker

.env.example

@@ -0,0 +1,6 @@
+DATABASE_URL=postgres://tracker:tracker@localhost:5432/tracker?sslmode=disable
+JWT_SECRET=dev-secret-change-me
+FCM_CREDENTIALS_FILE=
+LOCATION_RETENTION_DAYS=30
+WS_PING_INTERVAL=30s
+PORT=8080

.gitignore

@@ -1,2 +1,5 @@
 .worktrees/
 .superpowers/
+.env
+*.exe
+/server/tracker

Dockerfile

@@ -0,0 +1,12 @@
+FROM golang:1.25-alpine AS builder
+WORKDIR /build
+COPY server/go.mod ./
+COPY server/go.sum* ./
+RUN go mod download
+COPY server/ .
+RUN CGO_ENABLED=0 go build -o /tracker ./cmd/tracker
+
+FROM alpine:3.19
+RUN apk add --no-cache ca-certificates
+COPY --from=builder /tracker /usr/local/bin/tracker
+ENTRYPOINT ["tracker"]

docker-compose.yml

@@ -0,0 +1,33 @@
+services:
+  postgres:
+    image: postgis/postgis:16-3.4
+    environment:
+      POSTGRES_USER: tracker
+      POSTGRES_PASSWORD: tracker
+      POSTGRES_DB: tracker
+    ports:
+      - "5434:5432"
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U tracker"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+
+  tracker-server:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    ports:
+      - "8080:8080"
+    environment:
+      DATABASE_URL: postgres://tracker:tracker@postgres:5432/tracker?sslmode=disable
+      JWT_SECRET: dev-secret-change-me
+      PORT: "8080"
+    depends_on:
+      postgres:
+        condition: service_healthy
+
+volumes:
+  pgdata:

server/cmd/tracker/main.go

@@ -0,0 +1,118 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"strconv"
+	"syscall"
+	"time"
+
+	"github.com/nschatz/tracker/server/internal/api"
+	"github.com/nschatz/tracker/server/internal/auth"
+	"github.com/nschatz/tracker/server/internal/geo"
+	"github.com/nschatz/tracker/server/internal/notify"
+	"github.com/nschatz/tracker/server/internal/store"
+	"github.com/nschatz/tracker/server/internal/ws"
+)
+
+func main() {
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	port := envOrDefault("PORT", "8080")
+	dbURL := requireEnv("DATABASE_URL")
+	jwtSecret := requireEnv("JWT_SECRET")
+	fcmCreds := os.Getenv("FCM_CREDENTIALS_FILE")
+	retentionDays := envIntOrDefault("LOCATION_RETENTION_DAYS", 30)
+
+	db, err := store.New(ctx, dbURL)
+	if err != nil {
+		log.Fatalf("database: %v", err)
+	}
+	defer db.Close()
+
+	a := auth.New(jwtSecret)
+	hub := ws.NewHub()
+	go hub.Run()
+
+	var sender notify.Sender
+	if fcmCreds != "" {
+		s, err := notify.NewFCMSender(ctx, fcmCreds)
+		if err != nil {
+			log.Fatalf("fcm: %v", err)
+		}
+		sender = s
+	} else {
+		log.Println("WARNING: FCM_CREDENTIALS_FILE not set, using noop sender")
+		sender = notify.NoopSender{}
+	}
+	notifier := notify.NewNotifier(sender)
+	geoTracker := geo.NewTracker()
+
+	srv := api.NewServer(a, db, db, db, db, hub, geoTracker, notifier, db, db)
+
+	go runRetention(ctx, db, retentionDays)
+
+	httpSrv := &http.Server{Addr: ":" + port, Handler: srv}
+	go func() {
+		<-ctx.Done()
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+		httpSrv.Shutdown(shutdownCtx)
+	}()
+
+	log.Printf("listening on :%s", port)
+	if err := httpSrv.ListenAndServe(); err != http.ErrServerClosed {
+		log.Fatalf("http: %v", err)
+	}
+}
+
+func runRetention(ctx context.Context, db interface {
+	DeleteLocationsOlderThan(context.Context, int) (int64, error)
+}, days int) {
+	ticker := time.NewTicker(24 * time.Hour)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			count, err := db.DeleteLocationsOlderThan(ctx, days)
+			if err != nil {
+				log.Printf("retention: %v", err)
+			} else if count > 0 {
+				log.Printf("retention: deleted %d old location rows", count)
+			}
+		}
+	}
+}
+
+func envOrDefault(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}
+
+func requireEnv(key string) string {
+	v := os.Getenv(key)
+	if v == "" {
+		log.Fatalf("required env var %s is not set", key)
+	}
+	return v
+}
+
+func envIntOrDefault(key string, fallback int) int {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		log.Fatalf("env var %s must be an integer: %v", key, err)
+	}
+	return n
+}

server/go.mod

@@ -0,0 +1,68 @@
+module github.com/nschatz/tracker/server
+
+go 1.25.0
+
+require (
+	cel.dev/expr v0.25.1 // indirect
+	cloud.google.com/go v0.123.0 // indirect
+	cloud.google.com/go/auth v0.18.2 // indirect
+	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
+	cloud.google.com/go/compute/metadata v0.9.0 // indirect
+	cloud.google.com/go/firestore v1.21.0 // indirect
+	cloud.google.com/go/iam v1.5.3 // indirect
+	cloud.google.com/go/longrunning v0.8.0 // indirect
+	cloud.google.com/go/monitoring v1.24.3 // indirect
+	cloud.google.com/go/storage v1.56.0 // indirect
+	firebase.google.com/go/v4 v4.19.0 // indirect
+	github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.30.0 // indirect
+	github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/metric v0.53.0 // indirect
+	github.com/GoogleCloudPlatform/opentelemetry-operations-go/internal/resourcemapping v0.53.0 // indirect
+	github.com/MicahParks/keyfunc v1.9.0 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5 // indirect
+	github.com/envoyproxy/go-control-plane/envoy v1.36.0 // indirect
+	github.com/envoyproxy/protoc-gen-validate v1.3.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-chi/chi/v5 v5.2.5 // indirect
+	github.com/go-jose/go-jose/v4 v4.1.3 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/golang-jwt/jwt/v4 v4.5.2 // indirect
+	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect
+	github.com/golang/protobuf v1.5.4 // indirect
+	github.com/google/s2a-go v0.1.9 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.3.14 // indirect
+	github.com/googleapis/gax-go/v2 v2.19.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.9.1 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 // indirect
+	github.com/spiffe/go-spiffe/v2 v2.6.0 // indirect
+	github.com/zeebo/errs v1.4.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/contrib/detectors/gcp v1.39.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.61.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
+	go.opentelemetry.io/otel v1.42.0 // indirect
+	go.opentelemetry.io/otel/metric v1.42.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.42.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.42.0 // indirect
+	go.opentelemetry.io/otel/trace v1.42.0 // indirect
+	golang.org/x/crypto v0.49.0 // indirect
+	golang.org/x/net v0.52.0 // indirect
+	golang.org/x/oauth2 v0.36.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
+	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
+	golang.org/x/time v0.15.0 // indirect
+	google.golang.org/api v0.273.1 // indirect
+	google.golang.org/appengine/v2 v2.0.6 // indirect
+	google.golang.org/genproto v0.0.0-20260316180232-0b37fe3546d5 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20260316180232-0b37fe3546d5 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260319201613-d00831a3d3e7 // indirect
+	google.golang.org/grpc v1.79.3 // indirect
+	google.golang.org/protobuf v1.36.11 // indirect
+	nhooyr.io/websocket v1.8.17 // indirect
+)