Land feature 57's controller work on its release branch

The controller plans config, templates and moved providers' provisions,
hands bus accounts to the vault and judges the new manifest words, on the
feature's SDK and node-engine validator (feature 57, config and provisioning).

internal/builder/same_program_test.go

@@ -0,0 +1,126 @@
+package builder
+
+import (
+	"archive/tar"
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+)
+
+// aFilesystem is a filesystem tarball of files, each written at the time given.
+func aFilesystem(t *testing.T, at time.Time, files map[string]string) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	tw := tar.NewWriter(&buf)
+	for _, name := range []string{"usr/local/bin/mesh-builder", "etc/apk/world"} {
+		body, ok := files[name]
+		if !ok {
+			continue
+		}
+		if err := tw.WriteHeader(&tar.Header{Name: name, Mode: 0o755, Size: int64(len(body)), ModTime: at,
+			Typeflag: tar.TypeReg}); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := tw.Write([]byte(body)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := tw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	return buf.Bytes()
+}
+
+// anEngine answers the container engine's commands for images by reference: each image's filesystem and labels.
+func anEngine(images map[string][]byte, labels map[string]string, failing string) Runner {
+	created := map[string]string{}
+	return func(_ context.Context, _ string, name string, args ...string) (string, error) {
+		joined := strings.Join(args, " ")
+		ref := args[len(args)-1]
+		if failing != "" && strings.Contains(joined, failing) {
+			return "", fmt.Errorf("the engine refused %s", joined)
+		}
+		switch {
+		case args[0] == "pull", args[0] == "rm":
+			return "", nil
+		case args[0] == "image":
+			return fmt.Sprintf(`linux/amd64/ {"Entrypoint":["/usr/local/bin/mesh-builder"],"Labels":{"commit":%q}}`,
+				labels[ref]), nil
+		case args[0] == "create":
+			id := fmt.Sprintf("container%04d", len(created))
+			created[id] = ref
+			return id + "\n", nil
+		case args[0] == "export":
+			return "", os.WriteFile(args[2], images[created[ref]], 0o600)
+		}
+		return "", fmt.Errorf("unexpected %s %s", name, joined)
+	}
+}
+
+// TestAModuleWhoseProgramDidNotChangeIsSaidUnchanged is novox/hq issue 721: mesh-controller #335 changed one sentence
+// in a package mesh-builder imports and never reaches, and build-agent moved. Built again, its image differs only in
+// the files' times and its commit label, and the check says it is the same as the build the mesh holds.
+func TestAModuleWhoseProgramDidNotChangeIsSaidUnchanged(t *testing.T) {
+	held := map[string]string{"build-agent/agent": "store/build-agent@sha256:aaaa"}
+	made := []catalogue.Built{{Name: "agent", Kind: "image", Reference: "scratch/build-agent@sha256:bbbb"}}
+	files := map[string]string{"usr/local/bin/mesh-builder": "the same program", "etc/apk/world": "docker-cli\ngit\n"}
+	images := map[string][]byte{
+		"store/build-agent@sha256:aaaa":   aFilesystem(t, time.Unix(1000, 0), files),
+		"scratch/build-agent@sha256:bbbb": aFilesystem(t, time.Unix(2000, 0), files),
+	}
+	labels := map[string]string{"store/build-agent@sha256:aaaa": "a5500f73", "scratch/build-agent@sha256:bbbb": "c2ec0a60"}
+	same, against, err := sameAsHeld(context.Background(), anEngine(images, labels, ""), t.TempDir(), "build-agent",
+		made, held)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.HasPrefix(same, "unchanged: its program is the same as running build agent") ||
+		against["agent"] != held["build-agent/agent"] {
+		t.Fatalf("an image the same but for its times and labels is not said unchanged: %q %v", same, against)
+	}
+
+	// **Any file differing moves it**, not only its program.
+	changed := map[string]string{"usr/local/bin/mesh-builder": "the same program", "etc/apk/world": "docker-cli\ngit\ncurl\n"}
+	images["scratch/build-agent@sha256:bbbb"] = aFilesystem(t, time.Unix(2000, 0), changed)
+	if same, _, err := sameAsHeld(context.Background(), anEngine(images, labels, ""), t.TempDir(), "build-agent", made,
+		held); err != nil || same != "" {
+		t.Fatalf("an image with another file is said unchanged: %q %v", same, err)
+	}
+
+	// **A comparison that fails says nothing**, and the module moves.
+	images["scratch/build-agent@sha256:bbbb"] = aFilesystem(t, time.Unix(2000, 0), files)
+	if same, _, err := sameAsHeld(context.Background(), anEngine(images, labels, "export"), t.TempDir(), "build-agent",
+		made, held); err == nil || same != "" {
+		t.Fatalf("a comparison that failed said %q, %v", same, err)
+	}
+
+	// No held build, or an artifact that is not an image: nothing compared.
+	if same, _, _ := sameAsHeld(context.Background(), anEngine(images, labels, ""), t.TempDir(), "build-agent", made,
+		nil); same != "" {
+		t.Fatalf("a module the mesh holds no build of is said unchanged: %q", same)
+	}
+	archive := []catalogue.Built{{Name: "agent", Kind: "archive", Reference: "scratch/build-agent@sha256:bbbb"}}
+	if same, _, _ := sameAsHeld(context.Background(), anEngine(images, labels, ""), t.TempDir(), "build-agent",
+		archive, held); same != "" {
+		t.Fatalf("an archive is said unchanged without being compared: %q", same)
+	}
+}
+
+// TestAnImageWithAnotherEntrypointIsNotTheSame: the configuration counts, but for its labels.
+func TestAnImageWithAnotherEntrypointIsNotTheSame(t *testing.T) {
+	a, err := configContent(`linux/amd64/ {"Entrypoint":["/a"],"Labels":{"commit":"1"}}`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, _ := configContent(`linux/amd64/ {"Labels":{"commit":"2"},"Entrypoint":["/a"]}`)
+	c, _ := configContent(`linux/amd64/ {"Entrypoint":["/b"],"Labels":{"commit":"1"}}`)
+	if a != b || a == c {
+		t.Fatalf("labels count, or the entrypoint does not: %q %q %q", a, b, c)
+	}
+}