Allow setting architecture of containers

Support creating containers of multi-platform images for an architecture
other than that of the host running Complement.

Author: AndrewFerr

ENVIRONMENT.md

@@ -16,6 +16,15 @@ If 1, always prints the Homeserver container logs even on success. When used wit
 This allows you to override the base image used for a particular named homeserver. For example, `COMPLEMENT_BASE_IMAGE_HS1=complement-dendrite:latest` would use `complement-dendrite:latest` for the `hs1` homeserver in blueprints, but not any other homeserver (e.g `hs2`). This matching is case-insensitive. This allows Complement to test how different homeserver implementations work with each other.  
 - Type: `map[string]string`
 
+#### `COMPLEMENT_BASE_ARCH`
+This allows you to override the architecture of the Docker image to use as a base homeserver when generating blueprints. This can be used to emulate a particular architecture with a multi-platform image. If "", the architecture of the host running Complement is used.
+- Type: `string`
+- Default: ""
+
+#### `COMPLEMENT_BASE_ARCH_*`
+This allows you to set the architecture of the base image used for a particular named homeserver. For example, `COMPLEMENT_BASE_ARCH_HS1=arm64` would use an `arm64` for the `hs1` homeserver in blueprints, but not any other homeserver (e.g `hs2`). This matching is case-insensitive.
+- Type: `map[string]string`
+
 #### `COMPLEMENT_DEBUG`
 If 1, prints out more verbose logging such as HTTP request/response bodies.  
 - Type: `bool`

b/blueprints.go

@@ -55,6 +55,8 @@ type Homeserver struct {
 	ApplicationServices []ApplicationService
 	// Optionally override the baseImageURI for blueprint creation
 	BaseImageURI *string
+	// Optionally override the baseImageArch for blueprint creation
+	BaseImageArch *string
 }
 
 type User struct {

config/config.go

@@ -30,6 +30,12 @@ type Complement struct {
 	// blueprints. This image must conform to Complement's rules on containers, such as listening on the
 	// correct ports.
 	BaseImageURI string
+	// Name: COMPLEMENT_BASE_ARCH
+	// Default: ""
+	// Description: The architecture of the Docker image to use as a base homeserver when generating
+	// blueprints. This can be used to emulate a particular architecture with a multi-platform image.
+	// If "", the architecture of the host running Complement is used.
+	BaseImageArch string
 	// Name: COMPLEMENT_DEBUG
 	// Default: 0
 	// Description: If 1, prints out more verbose logging such as HTTP request/response bodies.
@@ -71,6 +77,11 @@ type Complement struct {
 	// for the `hs1` homeserver in blueprints, but not any other homeserver (e.g `hs2`). This matching
 	// is case-insensitive. This allows Complement to test how different homeserver implementations work with each other.
 	BaseImageURIs map[string]string
+	// Name: COMPLEMENT_BASE_ARCH_*
+	// Description: This allows you to set the architecture of the base image used for a particular named homeserver.
+	// For example, `COMPLEMENT_BASE_ARCH_HS1=arm64` would use an `arm64` image for the `hs1` homeserver in blueprints,
+	// but not any other homeserver (e.g `hs2`). This matching is case-insensitive.
+	BaseImageArchs map[string]string
 
 	// The namespace for all complement created blueprints and deployments
 	PackageNamespace string
@@ -118,14 +129,19 @@ type Complement struct {
 	PostTestScript string
 }
 
-var hsRegex = regexp.MustCompile(`COMPLEMENT_BASE_IMAGE_(.+)=(.+)$`)
+var hsUriRegex = regexp.MustCompile(`COMPLEMENT_BASE_IMAGE_(.+)=(.+)$`)
+var hsArchRegex = regexp.MustCompile(`COMPLEMENT_BASE_ARCH_(.+)=(.+)$`)
 
 func NewConfigFromEnvVars(pkgNamespace, baseImageURI string) *Complement {
-	cfg := &Complement{BaseImageURIs: map[string]string{}}
+	cfg := &Complement{
+		BaseImageURIs:  map[string]string{},
+		BaseImageArchs: map[string]string{},
+	}
 	cfg.BaseImageURI = os.Getenv("COMPLEMENT_BASE_IMAGE")
 	if cfg.BaseImageURI == "" {
 		cfg.BaseImageURI = baseImageURI
 	}
+	cfg.BaseImageArch = os.Getenv("COMPLEMENT_BASE_ARCH")
 	cfg.DebugLoggingEnabled = os.Getenv("COMPLEMENT_DEBUG") == "1"
 	cfg.AlwaysPrintServerLogs = os.Getenv("COMPLEMENT_ALWAYS_PRINT_SERVER_LOGS") == "1"
 	cfg.EnableDirtyRuns = os.Getenv("COMPLEMENT_ENABLE_DIRTY_RUNS") == "1"
@@ -153,10 +169,14 @@ func NewConfigFromEnvVars(pkgNamespace, baseImageURI string) *Complement {
 	for _, env := range os.Environ() {
 		// FindStringSubmatch returns the complete match as well as the capture groups.
 		// In this case we expect there to be 3 matches.
-		if matches := hsRegex.FindStringSubmatch(env); len(matches) == 3 {
+		if matches := hsUriRegex.FindStringSubmatch(env); len(matches) == 3 {
 			hs := matches[1]                   // first capture group; homeserver name
 			cfg.BaseImageURIs[hs] = matches[2] // second capture group; homeserver image
 		}
+		if matches := hsArchRegex.FindStringSubmatch(env); len(matches) == 3 {
+			hs := matches[1]                    // first capture group; homeserver name
+			cfg.BaseImageArchs[hs] = matches[2] // second capture group; homeserver arch
+		}
 	}
 
 	cfg.PackageNamespace = pkgNamespace

internal/docker/builder.go

@@ -398,18 +398,23 @@ func (d *Builder) constructHomeserver(blueprintName string, runner *instruction.
 func (d *Builder) deployBaseImage(blueprintName string, hs b.Homeserver, contextStr, networkName string) (*HomeserverDeployment, error) {
 	asIDToRegistrationMap := asIDToRegistrationFromLabels(labelsForApplicationServices(hs))
 	var baseImageURI string
+	var baseImageArch string
 	if hs.BaseImageURI == nil {
 		baseImageURI = d.Config.BaseImageURI
 		// Use HS specific base image if defined
 		if uri, ok := d.Config.BaseImageURIs[hs.Name]; ok {
 			baseImageURI = uri
 		}
+		if arch, ok := d.Config.BaseImageArchs[hs.Name]; ok {
+			baseImageArch = arch
+		}
 	} else {
 		baseImageURI = *hs.BaseImageURI
+		baseImageArch = *hs.BaseImageArch
 	}
 
 	return deployImage(
-		d.Docker, baseImageURI, fmt.Sprintf("complement_%s", contextStr),
+		d.Docker, baseImageURI, baseImageArch, fmt.Sprintf("complement_%s", contextStr),
 		d.Config.PackageNamespace, blueprintName, hs.Name, asIDToRegistrationMap, contextStr,
 		networkName, d.Config,
 	)

internal/docker/deployer.go

@@ -39,6 +39,7 @@ import (
 	"github.com/docker/docker/api/types/image"
 	"github.com/docker/docker/api/types/mount"
 	"github.com/docker/docker/api/types/network"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 
 	"github.com/matrix-org/complement/config"
 )
@@ -90,10 +91,14 @@ func (d *Deployer) CreateDirtyServer(hsName string) (*HomeserverDeployment, erro
 	if uri, ok := d.config.BaseImageURIs[hsName]; ok {
 		baseImageURI = uri
 	}
+	baseImageArch := d.config.BaseImageArch
+	if arch, ok := d.config.BaseImageArchs[hsName]; ok {
+		baseImageArch = arch
+	}
 
 	containerName := fmt.Sprintf("complement_%s_dirty_%s", d.config.PackageNamespace, hsName)
 	hsDeployment, err := deployImage(
-		d.Docker, baseImageURI, containerName,
+		d.Docker, baseImageURI, baseImageArch, containerName,
 		d.config.PackageNamespace, "", hsName, nil, "dirty",
 		networkName, d.config,
 	)
@@ -172,7 +177,7 @@ func (d *Deployer) Deploy(ctx context.Context, blueprintName string) (*Deploymen
 		// TODO: Make CSAPI port configurable
 		containerName := fmt.Sprintf("complement_%s_%s_%s_%d", d.config.PackageNamespace, d.DeployNamespace, contextStr, counter)
 		deployment, err := deployImage(
-			d.Docker, img.ID, containerName,
+			d.Docker, img.ID, "", containerName,
 			d.config.PackageNamespace, blueprintName, hsName, asIDToRegistrationMap, contextStr, networkName, d.config,
 		)
 		if err != nil {
@@ -329,7 +334,7 @@ func (d *Deployer) StartServer(hsDep *HomeserverDeployment) error {
 
 // nolint
 func deployImage(
-	docker *client.Client, imageID string, containerName, pkgNamespace, blueprintName, hsName string,
+	docker *client.Client, imageID, imageArch, containerName, pkgNamespace, blueprintName, hsName string,
 	asIDToRegistrationMap map[string]string, contextStr, networkName string, cfg *config.Complement,
 ) (*HomeserverDeployment, error) {
 	ctx := context.Background()
@@ -402,7 +407,10 @@ func deployImage(
 				Aliases: []string{hsName},
 			},
 		},
-	}, nil, containerName)
+	}, &ocispec.Platform{
+		OS:           "linux",
+		Architecture: imageArch,
+	}, containerName)
 	if err != nil {
 		return nil, err
 	}