Add docker compose files in example-mysql (#99)

* Add docker compose files in example-mysql

* Update the example-mysql Docker image to `alpine`

* Initialize database schema with `multiStatements=true`

* Add `CGO_ENABLED=0` when building example-mysql

* Add logs to `initDatabaseSchema`

cmd/example-mysql/docker/Dockerfile

@@ -0,0 +1,16 @@
+FROM golang:1.22.5-bookworm@sha256:af9b40f2b1851be993763b85288f8434af87b5678af04355b1e33ff530b5765f as build
+
+WORKDIR /build
+
+# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
+COPY go.mod go.sum ./
+RUN go mod download && go mod verify
+
+COPY . .
+RUN CGO_ENABLED=0 go build -v ./cmd/example-mysql
+
+FROM alpine:3.20@sha256:0a4eaa0eecf5f8c050e5bba433f58c052be7587ee8af3e8b3910ef9ab5fbe9f5
+
+COPY --from=build /build/example-mysql /build/cmd/example-mysql/docker/testdata/key /build/cmd/example-mysql/docker/testdata/key.pub /build/storage/mysql/schema.sql /
+
+ENTRYPOINT ["/example-mysql"]

cmd/example-mysql/docker/compose.yaml

@@ -0,0 +1,37 @@
+services:
+
+  tessera-example-mysql-db:
+    container_name: tessera-mysql-db
+    image: "mysql:8.4"
+    ports:
+      - "3306:3306"
+    environment:
+      - MYSQL_ROOT_PASSWORD=tessera
+      - MYSQL_DATABASE=tessera
+      - MYSQL_USER=tessera
+      - MYSQL_PASSWORD=tessera
+    restart: always
+    healthcheck:
+      test: mysql --user=$$MYSQL_USER --password=$$MYSQL_PASSWORD --silent --execute "SHOW DATABASES;"
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+  tessera-example-mysql:
+    container_name: tessera-example-mysql
+    build:
+      context: ../../../
+      dockerfile: ./cmd/example-mysql/docker/Dockerfile
+    ports:
+      - "2024:2024"
+    command: [
+      "--mysql_uri=tessera:tessera@tcp(tessera-example-mysql-db:3306)/tessera",
+      "--init_schema_path=/schema.sql",
+      "--private_key_path=/key",
+      "--public_key_path=/key.pub",
+      "--alsologtostderr",
+    ]
+    restart: always
+    depends_on:
+      tessera-example-mysql-db:
+        condition: service_healthy

cmd/example-mysql/docker/testdata/key

@@ -0,0 +1 @@
+PRIVATE+KEY+Test-Betty+df84580a+Afge8kCzBXU7jb3cV2Q363oNXCufJ6u9mjOY1BGRY9E2

cmd/example-mysql/docker/testdata/key.pub

@@ -0,0 +1 @@
+Test-Betty+df84580a+AQQASqPUZoIHcJAF5mBOryctwFdTV1E0GRY4kEAtTzwB

cmd/example-mysql/main.go

@@ -38,6 +38,7 @@ var (
 	dbConnMaxLifetime = flag.Duration("db_conn_max_lifetime", 3*time.Minute, "")
 	dbMaxOpenConns    = flag.Int("db_max_open_conns", 64, "")
 	dbMaxIdleConns    = flag.Int("db_max_idle_conns", 64, "")
+	initSchemaPath    = flag.String("init_schema_path", "", "Location of the schema file if database initialization is needed")
 	listen            = flag.String("listen", ":2024", "Address:port to listen on")
 	privateKeyPath    = flag.String("private_key_path", "", "Location of private key file")
 	publicKeyPath     = flag.String("public_key_path", "", "Location of public key file")
@@ -56,6 +57,8 @@ func main() {
 	db.SetMaxOpenConns(*dbMaxOpenConns)
 	db.SetMaxIdleConns(*dbMaxIdleConns)
 
+	initDatabaseSchema(ctx)
+
 	rawPrivateKey, err := os.ReadFile(*privateKeyPath)
 	if err != nil {
 		klog.Exitf("Failed to read private key file %q: %v", *privateKeyPath, err)
@@ -242,3 +245,29 @@ func parseTileIndexWidth(index string) (uint64, uint64, error) {
 
 	return i, w, nil
 }
+
+func initDatabaseSchema(ctx context.Context) {
+	if *initSchemaPath != "" {
+		klog.Infof("Initializing database schema")
+
+		db, err := sql.Open("mysql", *mysqlURI+"?multiStatements=true")
+		if err != nil {
+			klog.Exitf("Failed to connect to DB: %v", err)
+		}
+		defer func() {
+			if err := db.Close(); err != nil {
+				klog.Warningf("Failed to close db: %v", err)
+			}
+		}()
+
+		rawSchema, err := os.ReadFile(*initSchemaPath)
+		if err != nil {
+			klog.Exitf("Failed to read init schema file %q: %v", *initSchemaPath, err)
+		}
+		if _, err := db.ExecContext(ctx, string(rawSchema)); err != nil {
+			klog.Exitf("Failed to execute init database schema: %v", err)
+		}
+
+		klog.Infof("Database schema initialized")
+	}
+}