GCloud¶

Since testcontainers-go v0.25.0

Introduction¶

The Testcontainers module for GCloud.

Adding this module to your project dependencies¶

Please run the following command to add the GCloud module to your Go dependencies:

go get github.com/testcontainers/testcontainers-go/modules/gcloud

Usage example¶

Info

By default, the all the emulators use gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators as the default Docker image, except for the BigQuery emulator, which uses ghcr.io/goccy/bigquery-emulator:0.4.3, and Spanner, which uses gcr.io/cloud-spanner-emulator/emulator:1.4.0.

BigQuery¶

Creating a BigQuery containerObtaining a BigQuery client

ctx := context.Background()

bigQueryContainer, err := gcloud.RunBigQueryContainer(
    ctx,
    testcontainers.WithImage("ghcr.io/goccy/bigquery-emulator:0.4.3"),
    gcloud.WithProjectID("bigquery-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := bigQueryContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectID := bigQueryContainer.Settings.ProjectID

opts := []option.ClientOption{
    option.WithEndpoint(bigQueryContainer.URI),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
    option.WithoutAuthentication(),
    internaloption.SkipDialSettingsValidation(),
}

client, err := bigquery.NewClient(ctx, projectID, opts...)
if err != nil {
    panic(err)
}
defer client.Close()

It's important to set the option.WithEndpoint() option using the container's URI, as shown in the client example above.

BigTable¶

Creating a BigTable containerObtaining a BigTable Admin clientObtaining a BigTable client

ctx := context.Background()

bigTableContainer, err := gcloud.RunBigTableContainer(
    ctx,
    testcontainers.WithImage("gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators"),
    gcloud.WithProjectID("bigtable-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := bigTableContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectId := bigTableContainer.Settings.ProjectID

const (
    instanceId = "test-instance"
    tableName  = "test-table"
)

options := []option.ClientOption{
    option.WithEndpoint(bigTableContainer.URI),
    option.WithoutAuthentication(),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
}
adminClient, err := bigtable.NewAdminClient(ctx, projectId, instanceId, options...)
if err != nil {
    panic(err)
}
defer adminClient.Close()

client, err := bigtable.NewClient(ctx, projectId, instanceId, options...)
if err != nil {
    panic(err)
}
defer client.Close()

It's important to set the option.WithEndpoint() option using the container's URI, as shown in the Admin client example above.

Datastore¶

Creating a Datastore containerObtaining a Datastore client

ctx := context.Background()

datastoreContainer, err := gcloud.RunDatastoreContainer(
    ctx,
    testcontainers.WithImage("gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators"),
    gcloud.WithProjectID("datastore-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := datastoreContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectID := datastoreContainer.Settings.ProjectID

options := []option.ClientOption{
    option.WithEndpoint(datastoreContainer.URI),
    option.WithoutAuthentication(),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
}

dsClient, err := datastore.NewClient(ctx, projectID, options...)
if err != nil {
    panic(err)
}
defer dsClient.Close()

It's important to set the option.WithEndpoint() option using the container's URI, as shown in the client example above.

Firestore¶

Creating a Firestore containerObtaining a Firestore client

ctx := context.Background()

firestoreContainer, err := gcloud.RunFirestoreContainer(
    ctx,
    testcontainers.WithImage("gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators"),
    gcloud.WithProjectID("firestore-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := firestoreContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectID := firestoreContainer.Settings.ProjectID

conn, err := grpc.Dial(firestoreContainer.URI, grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithPerRPCCredentials(emulatorCreds{}))
if err != nil {
    panic(err)
}

options := []option.ClientOption{option.WithGRPCConn(conn)}
client, err := firestore.NewClient(ctx, projectID, options...)
if err != nil {
    panic(err)
}
defer client.Close()

It's important to set the target string of the grpc.Dial method using the container's URI, as shown in the client example above.

Pubsub¶

Creating a Pubsub containerObtaining a Pubsub client

ctx := context.Background()

pubsubContainer, err := gcloud.RunPubsubContainer(
    ctx,
    testcontainers.WithImage("gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators"),
    gcloud.WithProjectID("pubsub-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := pubsubContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectID := pubsubContainer.Settings.ProjectID

conn, err := grpc.Dial(pubsubContainer.URI, grpc.WithTransportCredentials(insecure.NewCredentials()))
if err != nil {
    panic(err)
}

options := []option.ClientOption{option.WithGRPCConn(conn)}
client, err := pubsub.NewClient(ctx, projectID, options...)
if err != nil {
    panic(err)
}
defer client.Close()

It's important to set the target string of the grpc.Dial method using the container's URI, as shown in the client example above.

Spanner¶

Creating a Spanner containerObtaining a Spanner Admin clientObtaining a Spanner Database Admin client

ctx := context.Background()

spannerContainer, err := gcloud.RunSpannerContainer(
    ctx,
    testcontainers.WithImage("gcr.io/cloud-spanner-emulator/emulator:1.4.0"),
    gcloud.WithProjectID("spanner-project"),
)
if err != nil {
    panic(err)
}

// Clean up the container
defer func() {
    if err := spannerContainer.Terminate(ctx); err != nil {
        panic(err)
    }
}()

projectId := spannerContainer.Settings.ProjectID

const (
    instanceId   = "test-instance"
    databaseName = "test-db"
)

options := []option.ClientOption{
    option.WithEndpoint(spannerContainer.URI),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
    option.WithoutAuthentication(),
    internaloption.SkipDialSettingsValidation(),
}

instanceAdmin, err := instance.NewInstanceAdminClient(ctx, options...)
if err != nil {
    panic(err)
}
defer instanceAdmin.Close()

c, err := database.NewDatabaseAdminClient(ctx, options...)
if err != nil {
    panic(err)
}
defer c.Close()

It's important to set the option.WithEndpoint() option using the container's URI, as shown in the Admin client example above.

Module reference¶

The GCloud module exposes one entrypoint function to create the different GCloud emulators, and each function receives two parameters:

func RunBigQueryContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*BigQueryContainer, error)
func RunBigTableContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*BigTableContainer, error)
func RunDatastoreContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*DatastoreContainer, error)
func RunFirestoreContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*FirestoreContainer, error)
func RunPubsubContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*PubsubContainer, error)
func RunSpannerContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*SpannerContainer, error)

context.Context, the Go context.
testcontainers.ContainerCustomizer, a variadic argument for passing options.

Container Options¶

When starting any of the GCloud containers, you can pass options in a variadic way to configure it.

Image¶

If you need to set a different GCloud Docker image, you can use testcontainers.WithImage with a valid Docker image for GCloud. E.g. testcontainers.WithImage("gcr.io/google.com/cloudsdktool/cloud-sdk:367.0.0-emulators").

Image Substitutions¶

Since testcontainers-go v0.26.0

In more locked down / secured environments, it can be problematic to pull images from Docker Hub and run them without additional precautions.

An image name substitutor converts a Docker image name, as may be specified in code, to an alternative name. This is intended to provide a way to override image names, for example to enforce pulling of images from a private registry.

Testcontainers for Go exposes an interface to perform this operations: ImageSubstitutor, and a No-operation implementation to be used as reference for custom implementations:

Image Substitutor InterfaceNoop Image Substitutor

// ImageSubstitutor represents a way to substitute container image names
type ImageSubstitutor interface {
    // Description returns the name of the type and a short description of how it modifies the image.
    // Useful to be printed in logs
    Description() string
    Substitute(image string) (string, error)
}

type NoopImageSubstitutor struct{}

// Description returns a description of what is expected from this Substitutor,
// which is used in logs.
func (s NoopImageSubstitutor) Description() string {
    return "NoopImageSubstitutor (noop)"
}

// Substitute returns the original image, without any change
func (s NoopImageSubstitutor) Substitute(image string) (string, error) {
    return image, nil
}

Using the WithImageSubstitutors options, you could define your own substitutions to the container images. E.g. adding a prefix to the images so that they can be pulled from a Docker registry other than Docker Hub. This is the usual mechanism for using Docker image proxies, caches, etc.

Wait Strategies¶

If you need to set a different wait strategy for the container, you can use testcontainers.WithWaitStrategy with a valid wait strategy.

Info

The default deadline for the wait strategy is 60 seconds.

At the same time, it's possible to set a wait strategy and a custom deadline with testcontainers.WithWaitStrategyAndDeadline.

Startup Commands¶

Since testcontainers-go v0.25.0

Testcontainers exposes the WithStartupCommand(e ...Executable) option to run arbitrary commands in the container right after it's started.

Info

To better understand how this feature works, please read the Create containers: Lifecycle Hooks documentation.

It also exports an Executable interface, defining one single method: AsCommand(), which returns a slice of strings to represent the command and positional arguments to be executed in the container.

You could use this feature to run a custom script, or to run a command that is not supported by the module right after the container is started.

Docker type modifiers¶

If you need an advanced configuration for the container, you can leverage the following Docker type modifiers:

testcontainers.WithConfigModifier
testcontainers.WithHostConfigModifier
testcontainers.WithEndpointSettingsModifier

Please read the Create containers: Advanced Settings documentation for more information.

Container Methods¶

The GCloud container exposes the following methods: