Don't pull images in k8s (#889)

As part of refactoring the runtime interface, I caused the proxy process to attempt to pull down images when running in k8s. Handle this with a conditional guard for now. Given the current plan to split the k8s logic apart further, we may come up with a more natural split in future. At very least, we can consider having a no-op image puller.

Author: dmjb

cmd/thv/app/run.go

@@ -11,6 +11,7 @@ import (
 	"github.com/stacklok/toolhive/pkg/logger"
 	"github.com/stacklok/toolhive/pkg/permissions"
 	"github.com/stacklok/toolhive/pkg/process"
+	"github.com/stacklok/toolhive/pkg/registry"
 	"github.com/stacklok/toolhive/pkg/runner"
 	"github.com/stacklok/toolhive/pkg/runner/retriever"
 	"github.com/stacklok/toolhive/pkg/transport"
@@ -242,12 +243,20 @@ func runCmdFunc(cmd *cobra.Command, args []string) error {
 		envVarValidator = &runner.CLIEnvVarValidator{}
 	}
 
-	// Take the MCP server we were supplied and either fetch the image, or
-	// build it from a protocol scheme. If the server URI refers to an image
-	// in our trusted registry, we will also fetch the image metadata.
-	imageURL, imageMetadata, err := retriever.GetMCPServer(ctx, serverOrImage, runCACertPath, runVerifyImage)
-	if err != nil {
-		return fmt.Errorf("failed to find or create the MCP server %s: %v", serverOrImage, err)
+	var imageMetadata *registry.ImageMetadata
+	imageURL := serverOrImage
+
+	// Only pull image if we are not running in Kubernetes mode.
+	// This split will go away if we implement a separate command or binary
+	// for running MCP servers in Kubernetes.
+	if !container.IsKubernetesRuntime() {
+		// Take the MCP server we were supplied and either fetch the image, or
+		// build it from a protocol scheme. If the server URI refers to an image
+		// in our trusted registry, we will also fetch the image metadata.
+		imageURL, imageMetadata, err = retriever.GetMCPServer(ctx, serverOrImage, runCACertPath, runVerifyImage)
+		if err != nil {
+			return fmt.Errorf("failed to find or create the MCP server %s: %v", serverOrImage, err)
+		}
 	}
 
 	// Initialize a new RunConfig with values from command-line flags