fix(provisioner): seed configs before container start

workspace-server/internal/provisioner/provisioner.go

@@ -481,6 +481,22 @@ func (p *Provisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string, e
 		return "", fmt.Errorf("failed to create container: %w", err)
 	}
 
+	// Seed /configs before the entrypoint starts. molecule-runtime reads
+	// /configs/config.yaml immediately; post-start copy races fast runtimes
+	// into a FileNotFoundError crash loop.
+	if cfg.TemplatePath != "" {
+		if err := p.CopyTemplateToContainer(ctx, resp.ID, cfg.TemplatePath); err != nil {
+			_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
+			return "", fmt.Errorf("failed to copy template to container %s before start: %w", name, err)
+		}
+	}
+	if len(cfg.ConfigFiles) > 0 {
+		if err := p.WriteFilesToContainer(ctx, resp.ID, cfg.ConfigFiles); err != nil {
+			_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
+			return "", fmt.Errorf("failed to write config files to container %s before start: %w", name, err)
+		}
+	}
+
 	if err := p.cli.ContainerStart(ctx, resp.ID, container.StartOptions{}); err != nil {
 		// Clean up created container on start failure
 		_ = p.cli.ContainerRemove(ctx, resp.ID, container.RemoveOptions{Force: true})
@@ -496,20 +512,6 @@ func (p *Provisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string, e
 	// /configs and /workspace, then drops to agent via gosu). No per-start
 	// chown needed here.
 
-	// Copy template files into /configs if TemplatePath is set
-	if cfg.TemplatePath != "" {
-		if err := p.CopyTemplateToContainer(ctx, resp.ID, cfg.TemplatePath); err != nil {
-			log.Printf("Provisioner: warning — failed to copy template to container %s: %v", name, err)
-		}
-	}
-
-	// Write generated config files into /configs if ConfigFiles is set
-	if len(cfg.ConfigFiles) > 0 {
-		if err := p.WriteFilesToContainer(ctx, resp.ID, cfg.ConfigFiles); err != nil {
-			log.Printf("Provisioner: warning — failed to write config files to container %s: %v", name, err)
-		}
-	}
-
 	// Resolve the host-mapped port. Retry inspect up to 3 times if Docker hasn't
 	// bound the ephemeral port yet (rare race under heavy load).
 	hostURL := InternalURL(cfg.WorkspaceID) // fallback to Docker-internal

workspace-server/internal/provisioner/provisioner_test.go

@@ -62,6 +62,24 @@ func TestValidateConfigSource_TemplateIsDirName(t *testing.T) {
 	}
 }
 
+func TestStartSeedsConfigsBeforeContainerStart(t *testing.T) {
+	src, err := os.ReadFile("provisioner.go")
+	if err != nil {
+		t.Fatalf("read provisioner.go: %v", err)
+	}
+	text := string(src)
+	copyTemplate := strings.Index(text, "p.CopyTemplateToContainer(ctx, resp.ID, cfg.TemplatePath)")
+	writeFiles := strings.Index(text, "p.WriteFilesToContainer(ctx, resp.ID, cfg.ConfigFiles)")
+	start := strings.Index(text, "p.cli.ContainerStart(ctx, resp.ID, container.StartOptions{})")
+
+	if copyTemplate < 0 || writeFiles < 0 || start < 0 {
+		t.Fatalf("expected Start to copy template, write config files, and start container")
+	}
+	if !(copyTemplate < start && writeFiles < start) {
+		t.Fatalf("config seeding must happen before ContainerStart: copyTemplate=%d writeFiles=%d start=%d", copyTemplate, writeFiles, start)
+	}
+}
+
 // baseHostConfig returns a fresh HostConfig with typical pre-tier binds,
 // mimicking what Start() builds before calling ApplyTierConfig.
 func baseHostConfig(pluginsPath string) *container.HostConfig {