feat(mongodb): add replica set support via opts (#2469)

* feat(mongodb): add WithReplicaSet option

The `WithReplicaSet` option configures the MongoDB container to run a
single-node replica set named "rs". The container will wait until the
replica set is ready.

* docs: document the new option

* fix: proper indent

---------

Co-authored-by: Manuel de la Peña <mdelapenya@gmail.com>

docs/modules/mongodb.md

@@ -58,6 +58,12 @@ It is used in conjunction with `WithUsername` to set a username and its password
 
 E.g. `testcontainers.WithPassword("mymongopwd")`.
 
+#### WithReplicaSet
+
+- Not available until the next release of testcontainers-go <a href="https://github.com/testcontainers/testcontainers-go"><span class="tc-version">:material-tag: main</span></a>
+
+The `WithReplicaSet` functional option configures the container to run a single-node MongoDB replica set named `rs`. The MongoDB container will wait until the replica set is ready.
+
 {% include "../features/common_functional_options.md" %}
 
 ### Container Methods

modules/mongodb/mongodb.go

@@ -79,6 +79,29 @@ func WithPassword(password string) testcontainers.CustomizeRequestOption {
 	}
 }
 
+// WithReplicaSet configures the container to run a single-node MongoDB replica set named "rs".
+// It will wait until the replica set is ready.
+func WithReplicaSet() testcontainers.CustomizeRequestOption {
+	return func(req *testcontainers.GenericContainerRequest) error {
+		req.Cmd = append(req.Cmd, "--replSet", "rs")
+		req.LifecycleHooks = append(req.LifecycleHooks, testcontainers.ContainerLifecycleHooks{
+			PostStarts: []testcontainers.ContainerHook{
+				func(ctx context.Context, c testcontainers.Container) error {
+					ip, err := c.ContainerIP(ctx)
+					if err != nil {
+						return err
+					}
+
+					cmd := eval("rs.initiate({ _id: 'rs', members: [ { _id: 0, host: '%s:27017' } ] })", ip)
+					return wait.ForExec(cmd).WaitUntilReady(ctx, c)
+				},
+			},
+		})
+
+		return nil
+	}
+}
+
 // ConnectionString returns the connection string for the MongoDB container.
 // If you provide a username and a password, the connection string will also include them.
 func (c *MongoDBContainer) ConnectionString(ctx context.Context) (string, error) {
@@ -95,3 +118,15 @@ func (c *MongoDBContainer) ConnectionString(ctx context.Context) (string, error)
 	}
 	return c.Endpoint(ctx, "mongodb")
 }
+
+// eval builds an mongosh|mongo eval command.
+func eval(command string, args ...any) []string {
+	command = "\"" + fmt.Sprintf(command, args...) + "\""
+
+	return []string{
+		"sh",
+		"-c",
+		// In previous versions, the binary "mongosh" was named "mongo".
+		"mongosh --quiet --eval " + command + " || mongo --quiet --eval " + command,
+	}
+}

modules/mongodb/mongodb_test.go

@@ -14,50 +14,70 @@ import (
 
 func TestMongoDB(t *testing.T) {
 	type tests struct {
-		name  string
-		image string
+		name string
+		opts []testcontainers.ContainerCustomizer
 	}
 	testCases := []tests{
 		{
-			name:  "From Docker Hub",
-			image: "mongo:6",
+			name: "From Docker Hub",
+			opts: []testcontainers.ContainerCustomizer{
+				testcontainers.WithImage("mongo:6"),
+			},
 		},
 		{
-			name:  "Community Server",
-			image: "mongodb/mongodb-community-server:7.0.2-ubi8",
+			name: "Community Server",
+			opts: []testcontainers.ContainerCustomizer{
+				testcontainers.WithImage("mongodb/mongodb-community-server:7.0.2-ubi8"),
+			},
 		},
 		{
-			name:  "Enterprise Server",
-			image: "mongodb/mongodb-enterprise-server:7.0.0-ubi8",
+			name: "Enterprise Server",
+			opts: []testcontainers.ContainerCustomizer{
+				testcontainers.WithImage("mongodb/mongodb-enterprise-server:7.0.0-ubi8"),
+			},
+		},
+		{
+			name: "With Replica set and mongo:4",
+			opts: []testcontainers.ContainerCustomizer{
+				testcontainers.WithImage("mongo:4"),
+				mongodb.WithReplicaSet(),
+			},
+		},
+		{
+			name: "With Replica set and mongo:6",
+			opts: []testcontainers.ContainerCustomizer{
+				testcontainers.WithImage("mongo:6"),
+				mongodb.WithReplicaSet(),
+			},
 		},
 	}
 
 	for _, tc := range testCases {
-		image := tc.image
-		t.Run(image, func(t *testing.T) {
-			t.Parallel()
+		tc := tc
+		t.Run(tc.name, func(tt *testing.T) {
+			tt.Parallel()
 
 			ctx := context.Background()
 
-			mongodbContainer, err := mongodb.RunContainer(ctx, testcontainers.WithImage(image))
+			mongodbContainer, err := mongodb.RunContainer(ctx, tc.opts...)
 			if err != nil {
-				t.Fatalf("failed to start container: %s", err)
+				tt.Fatalf("failed to start container: %s", err)
 			}
 
 			defer func() {
 				if err := mongodbContainer.Terminate(ctx); err != nil {
-					t.Fatalf("failed to terminate container: %s", err)
+					tt.Fatalf("failed to terminate container: %s", err)
 				}
 			}()
 
 			endpoint, err := mongodbContainer.ConnectionString(ctx)
 			if err != nil {
-				t.Fatalf("failed to get connection string: %s", err)
+				tt.Fatalf("failed to get connection string: %s", err)
 			}
 
 			mongoClient, err := mongo.Connect(ctx, options.Client().ApplyURI(endpoint))
 			if err != nil {
-				t.Fatalf("failed to connect to MongoDB: %s", err)
+				tt.Fatalf("failed to connect to MongoDB: %s", err)
 			}
 
 			err = mongoClient.Ping(ctx, nil)
@@ -66,7 +86,7 @@ func TestMongoDB(t *testing.T) {
 			}
 
 			if mongoClient.Database("test").Name() != "test" {
-				t.Fatalf("failed to connect to the correct database")
+				tt.Fatalf("failed to connect to the correct database")
 			}
 		})
 	}