feat: move runtime config into cloudruntime package

With a specific context key, it becomes easier to mock the runtime in
unit tests.

BREAKING CHANGE: cloudrunner.Service replaced with cloudrunner.Runtime

cloudruntime/config.go

@@ -0,0 +1,59 @@
+package cloudruntime
+
+import "context"
+
+// WithConfig adds the provided runtime Config to the current context.
+func WithConfig(ctx context.Context, config Config) context.Context {
+	return context.WithValue(ctx, configContextKey{}, config)
+}
+
+// GetConfig gets the runtime Config from the current context.
+func GetConfig(ctx context.Context) (Config, bool) {
+	result, ok := ctx.Value(configContextKey{}).(Config)
+	return result, ok
+}
+
+type configContextKey struct{}
+
+// Config is the runtime config for the service.
+type Config struct {
+	// Port is the port the service is listening on.
+	Port int `env:"PORT" default:"8080"`
+	// Service is the name of the service.
+	Service string `env:"K_SERVICE"`
+	// Revision of the service, as assigned by a Knative runtime.
+	Revision string `env:"K_REVISION"`
+	// Configuration of the service, as assigned by a Knative runtime.
+	Configuration string `env:"K_CONFIGURATION"`
+	// ProjectID is the GCP project ID the service is running in.
+	// In production, defaults to the project where the service is deployed.
+	ProjectID string `env:"GOOGLE_CLOUD_PROJECT"`
+	// ServiceAccount is the service account used by the service.
+	// In production, defaults to the default service account of the running service.
+	ServiceAccount string
+	// ServiceVersion is the version of the service.
+	ServiceVersion string `env:"SERVICE_VERSION"`
+}
+
+// Autodetect the runtime config.
+func (c *Config) Autodetect() error {
+	if projectID, ok := ProjectID(); ok {
+		c.ProjectID = projectID
+	}
+	if serviceVersion, ok := ServiceVersion(); ok {
+		c.ServiceVersion = serviceVersion
+	}
+	if serviceAccount, ok := ServiceAccount(); ok {
+		c.ServiceAccount = serviceAccount
+	}
+	if service, ok := Service(); ok {
+		c.Service = service
+	}
+	if revision, ok := Revision(); ok {
+		c.Revision = revision
+	}
+	if configuration, ok := Configuration(); ok {
+		c.Configuration = configuration
+	}
+	return nil
+}

grpcserver.go

@@ -36,7 +36,7 @@ func ListenGRPC(ctx context.Context, grpcServer *grpc.Server) error {
 	if !ok {
 		return fmt.Errorf("cloudrunner.ListenGRPC: must be called with a context from cloudrunner.Run")
 	}
-	address := fmt.Sprintf(":%d", run.config.Service.Port)
+	address := fmt.Sprintf(":%d", run.config.Runtime.Port)
 	listener, err := (&net.ListenConfig{}).Listen(
 		ctx,
 		"tcp",

httphandler.go → httpserver.go

@@ -29,7 +29,7 @@ func NewHTTPServer(ctx context.Context, handler http.Handler, middlewares ...HTT
 		run.serverMiddleware.HTTPServer,
 	}
 	return &http.Server{
-		Addr: fmt.Sprintf(":%d", run.config.Service.Port),
+		Addr: fmt.Sprintf(":%d", run.config.Runtime.Port),
 		Handler: cloudserver.ChainHTTPMiddleware(
 			handler,
 			append(defaultMiddlewares, middlewares...)...,

run.go

@@ -12,6 +12,7 @@ import (
 	"go.einride.tech/cloudrunner/cloudotel"
 	"go.einride.tech/cloudrunner/cloudprofiler"
 	"go.einride.tech/cloudrunner/cloudrequestlog"
+	"go.einride.tech/cloudrunner/cloudruntime"
 	"go.einride.tech/cloudrunner/cloudserver"
 	"go.einride.tech/cloudrunner/cloudtrace"
 	"go.einride.tech/cloudrunner/cloudzap"
@@ -21,8 +22,8 @@ import (
 
 // runConfig configures the Run entrypoint from environment variables.
 type runConfig struct {
-	// Service contains generic service config.
-	Service ServiceConfig
+	// Runtime contains runtime config.
+	Runtime cloudruntime.Config
 	// Logger contains logger config.
 	Logger cloudzap.LoggerConfig
 	// Profiler contains profiler config.
@@ -66,14 +67,17 @@ func Run(fn func(context.Context) error, options ...Option) error {
 	if err := config.Load(); err != nil {
 		return fmt.Errorf("cloudrunner.Run: %w", err)
 	}
-	run.config.Service.loadFromRuntime()
+	if err := run.config.Runtime.Autodetect(); err != nil {
+		return fmt.Errorf("cloudrunner.Run: %w", err)
+	}
 	if *validate {
 		return nil
 	}
-	run.traceMiddleware.ProjectID = run.config.Service.ProjectID
+	run.traceMiddleware.ProjectID = run.config.Runtime.ProjectID
 	run.serverMiddleware.Config = run.config.Server
 	run.requestLoggerMiddleware.Config = run.config.RequestLogger
 	ctx = withRunContext(ctx, &run)
+	ctx = cloudruntime.WithConfig(ctx, run.config.Runtime)
 	logger, err := cloudzap.NewLogger(run.config.Logger)
 	if err != nil {
 		return fmt.Errorf("cloudrunner.Run: %w", err)

runtime.go

@@ -0,0 +1,16 @@
+package cloudrunner
+
+import (
+	"context"
+
+	"go.einride.tech/cloudrunner/cloudruntime"
+)
+
+// Runtime returns the runtime config for the current context.
+func Runtime(ctx context.Context) cloudruntime.Config {
+	config, ok := cloudruntime.GetConfig(ctx)
+	if !ok {
+		panic("cloudrunner.Runtime must be called with a context from cloudrunner.Run")
+	}
+	return config
+}