feat: add go-memory-load-mongo sample app

go-memory-load-mongo/.dockerignore

@@ -0,0 +1,29 @@
+# Go build outputs
+/bin/
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test artifacts
+*.test
+*.out
+coverage.txt
+coverage.html
+
+# Go vendor
+vendor/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Docker
+**/.git

go-memory-load-mongo/.env.example

@@ -0,0 +1,2 @@
+APP_PORT=8080
+MONGO_URI=mongodb://app_user:app_password@localhost:27017/orderdb?authSource=admin

go-memory-load-mongo/Dockerfile

@@ -0,0 +1,18 @@
+FROM golang:1.26-alpine AS build
+
+WORKDIR /app
+
+COPY go.mod go.sum* ./
+RUN go mod download
+
+COPY . .
+RUN go build -o /bin/api ./cmd/api
+
+FROM alpine:3.22
+
+WORKDIR /app
+COPY --from=build /bin/api /app/api
+
+EXPOSE 8080
+
+CMD ["/app/api"]

go-memory-load-mongo/cmd/api/main.go

@@ -0,0 +1,80 @@
+// Package main is the entry point for the load-test MongoDB API server.
+package main
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"loadtestmongoapi/internal/config"
+	"loadtestmongoapi/internal/database"
+	"loadtestmongoapi/internal/httpapi"
+	"loadtestmongoapi/internal/store"
+)
+
+func main() {
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+		Level: slog.LevelInfo,
+	}))
+
+	cfg, err := config.Load()
+	if err != nil {
+		logger.Error("load config", "error", err)
+		os.Exit(1)
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	client, db, err := database.Open(ctx, cfg.MongoURI, "orderdb")
+	if err != nil {
+		logger.Error("connect mongo", "error", err)
+		os.Exit(1)
+	}
+	defer func() {
+		disconnectCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		_ = client.Disconnect(disconnectCtx)
+	}()
+
+	st := store.New(db)
+
+	if err := st.EnsureIndexes(ctx); err != nil {
+		logger.Error("ensure indexes", "error", err)
+		os.Exit(1)
+	}
+
+	handler := httpapi.New(st, logger)
+
+	server := &http.Server{
+		Addr:              ":" + cfg.Port,
+		Handler:           handler,
+		ReadHeaderTimeout: 3 * time.Second,
+		ReadTimeout:       30 * time.Second,
+		WriteTimeout:      60 * time.Second,
+		IdleTimeout:       60 * time.Second,
+	}
+
+	go func() {
+		logger.Info("api listening", "addr", server.Addr)
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			logger.Error("listen and serve", "error", err)
+			stop()
+		}
+	}()
+
+	<-ctx.Done()
+	logger.Info("shutdown signal received")
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := server.Shutdown(shutdownCtx); err != nil {
+		logger.Error("graceful shutdown", "error", err)
+		os.Exit(1)
+	}
+}

go-memory-load-mongo/docker-compose.yml

@@ -0,0 +1,41 @@
+services:
+  db:
+    image: mongo:7
+    container_name: load-test-mongo-db
+    ports:
+      - "27017:27017"
+    volumes:
+      - mongo_data:/data/db
+    healthcheck:
+      test: ["CMD", "mongosh", "--quiet", "--eval", "db.adminCommand('ping').ok"]
+      interval: 5s
+      timeout: 5s
+      retries: 20
+
+  api:
+    build:
+      context: .
+    container_name: load-test-mongo-api
+    environment:
+      APP_PORT: "8080"
+      MONGO_URI: mongodb://db:27017/orderdb
+    ports:
+      - "8080:8080"
+    depends_on:
+      db:
+        condition: service_healthy
+
+  k6:
+    image: grafana/k6:0.49.0
+    profiles: ["loadtest"]
+    environment:
+      BASE_URL: http://api:8080
+    volumes:
+      - ./loadtest:/scripts:ro
+    depends_on:
+      api:
+        condition: service_started
+    entrypoint: ["k6"]
+
+volumes:
+  mongo_data:

go-memory-load-mongo/go.mod

@@ -0,0 +1,17 @@
+module loadtestmongoapi
+
+go 1.26
+
+require go.mongodb.org/mongo-driver/v2 v2.2.1
+
+require (
+	github.com/golang/snappy v1.0.0 // indirect
+	github.com/klauspost/compress v1.16.7 // indirect
+	github.com/xdg-go/pbkdf2 v1.0.0 // indirect
+	github.com/xdg-go/scram v1.1.2 // indirect
+	github.com/xdg-go/stringprep v1.0.4 // indirect
+	github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 // indirect
+	golang.org/x/crypto v0.33.0 // indirect
+	golang.org/x/sync v0.11.0 // indirect
+	golang.org/x/text v0.22.0 // indirect
+)

go-memory-load-mongo/go.sum

@@ -0,0 +1,48 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/snappy v1.0.0 h1:Oy607GVXHs7RtbggtPBnr2RmDArIsAefDwvrdWvRhGs=
+github.com/golang/snappy v1.0.0/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
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+github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 h1:ilQV1hzziu+LLM3zUTJ0trRztfwgjqKnBWNtSRkbmwM=
+github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78/go.mod h1:aL8wCCfTfSfmXjznFBSZNN13rSJjlIOI1fUNAtF7rmI=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+go.mongodb.org/mongo-driver/v2 v2.2.1 h1:w5xra3yyu/sGrziMzK1D0cRRaH/b7lWCSsoN6+WV6AM=
+go.mongodb.org/mongo-driver/v2 v2.2.1/go.mod h1:qQkDMhCGWl3FN509DfdPd4GRBLU/41zqF/k8eTRceps=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
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go-memory-load-mongo/internal/config/config.go

@@ -0,0 +1,35 @@
+// Package config handles configuration loading from environment variables.
+package config
+
+import (
+	"errors"
+	"os"
+	"strings"
+)
+
+type Config struct {
+	Port     string
+	MongoURI string
+}
+
+func Load() (Config, error) {
+	cfg := Config{
+		Port:     getEnv("APP_PORT", "8080"),
+		MongoURI: strings.TrimSpace(os.Getenv("MONGO_URI")),
+	}
+
+	if cfg.MongoURI == "" {
+		return Config{}, errors.New("MONGO_URI is required")
+	}
+
+	return cfg, nil
+}
+
+func getEnv(key, fallback string) string {
+	value := strings.TrimSpace(os.Getenv(key))
+	if value == "" {
+		return fallback
+	}
+
+	return value
+}

go-memory-load-mongo/internal/database/mongo.go

@@ -0,0 +1,47 @@
+// Package database provides MongoDB connection helpers.
+package database
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"go.mongodb.org/mongo-driver/v2/mongo"
+	"go.mongodb.org/mongo-driver/v2/mongo/options"
+	"go.mongodb.org/mongo-driver/v2/mongo/readpref"
+)
+
+// Open creates a new MongoDB client, verifies connectivity with retries, and
+// returns the client and the named database handle.
+func Open(ctx context.Context, uri, dbName string) (*mongo.Client, *mongo.Database, error) {
+	opts := options.Client().
+		ApplyURI(uri).
+		SetMaxPoolSize(25).
+		SetMinPoolSize(10).
+		SetMaxConnIdleTime(5 * time.Minute)
+
+	client, err := mongo.Connect(opts)
+	if err != nil {
+		return nil, nil, fmt.Errorf("connect mongo: %w", err)
+	}
+
+	var pingErr error
+	for attempt := 1; attempt <= 20; attempt++ {
+		pingCtx, cancel := context.WithTimeout(ctx, 3*time.Second)
+		pingErr = client.Ping(pingCtx, readpref.Primary())
+		cancel()
+		if pingErr == nil {
+			return client, client.Database(dbName), nil
+		}
+
+		select {
+		case <-ctx.Done():
+			_ = client.Disconnect(context.Background())
+			return nil, nil, fmt.Errorf("ping mongo: %w", ctx.Err())
+		case <-time.After(2 * time.Second):
+		}
+	}
+
+	_ = client.Disconnect(context.Background())
+	return nil, nil, fmt.Errorf("ping mongo after retries: %w", pingErr)
+}