A directory the mesh places: ${dir:<id>} and the pathless directory resource

The first executable slice of ADR 0112 / to-be 27, sized to what the
operator settled tonight: a module definition names no host path for
its own data. A directory resource may omit path; composition resolves
it to <root>/<module>/<id>, the root a node's setting on Rendering with
/var/lib as the default — which reproduces exactly the layout novox
converged to by hand. ${dir:<id>} names the place from a resource's
path, content, mounts, environment and env-files, the same shape as
${bound:…}. A directory that states a path keeps it and still answers
by name — that is the adopted-data placement, mssql its live case.

Resolved in the controller at composition, so the wire format and the
host change not at all; a reference naming no directory refuses at the
manifest and again at composition; nested fills are rebuilt, never
written into the manifest's own maps, because one manifest composes
for many nodes.

internal/catalogue/dir_into_test.go

@@ -0,0 +1,141 @@
+package catalogue
+
+// A directory the mesh places (novox/hq ADR 0112). These tests pin the contract: a pathless
+// directory resolves under the node's root, ${dir:…} names it from every field a host path can
+// live in, a stated path is the adopted-data placement and wins, an unknown reference refuses at
+// the manifest, and filling for one node never leaks into the next composition.
+
+import (
+	"strings"
+	"testing"
+)
+
+func placedModule() Manifest {
+	return Manifest{
+		Module: "photos",
+		Resources: []map[string]any{
+			{"id": "data", "type": "directory", "mode": "0700"},
+			{"id": "server-env", "type": "file", "path": "${dir:data}/server.env",
+				"content": "STORE=${dir:data}/objects\n"},
+			{"id": "server", "type": "container", "name": "photos-server",
+				"volumes":  []any{"${dir:data}:/data"},
+				"env":      map[string]any{"DATA": "${dir:data}/objects"},
+				"env-file": []any{"${dir:data}/server.env"}},
+		},
+	}
+}
+
+func TestAPathlessDirectoryResolvesUnderTheNodesRoot(t *testing.T) {
+	m := placedModule()
+	dirs := dirsFor(m, Rendering{})
+	if dirs["data"] != "/var/lib/photos/data" {
+		t.Fatalf("the default root is /var/lib and the shape is <root>/<module>/<id>; got %q", dirs["data"])
+	}
+	dirs = dirsFor(m, Rendering{DataRoot: "/tank/nox/"})
+	if dirs["data"] != "/tank/nox/photos/data" {
+		t.Fatalf("a node's own root is honoured, trailing slash and all; got %q", dirs["data"])
+	}
+}
+
+func TestDirReferencesBecomeThePlaceInEveryField(t *testing.T) {
+	m := placedModule()
+	dirs := dirsFor(m, Rendering{})
+
+	directory := shallowCopy(m.Resources[0])
+	if err := dirInto(directory, dirs, m.Module); err != nil {
+		t.Fatal(err)
+	}
+	if directory["path"] != "/var/lib/photos/data" {
+		t.Fatalf("a pathless directory receives its resolved path; got %v", directory["path"])
+	}
+
+	file := shallowCopy(m.Resources[1])
+	if err := dirInto(file, dirs, m.Module); err != nil {
+		t.Fatal(err)
+	}
+	if file["path"] != "/var/lib/photos/data/server.env" {
+		t.Fatalf("a file's path names the place; got %v", file["path"])
+	}
+	if file["content"] != "STORE=/var/lib/photos/data/objects\n" {
+		t.Fatalf("a file's content names the place; got %v", file["content"])
+	}
+
+	container := shallowCopy(m.Resources[2])
+	if err := dirInto(container, dirs, m.Module); err != nil {
+		t.Fatal(err)
+	}
+	if container["volumes"].([]any)[0] != "/var/lib/photos/data:/data" {
+		t.Fatalf("a mount names the place; got %v", container["volumes"])
+	}
+	if container["env"].(map[string]any)["DATA"] != "/var/lib/photos/data/objects" {
+		t.Fatalf("an environment value names the place; got %v", container["env"])
+	}
+	if container["env-file"].([]any)[0] != "/var/lib/photos/data/server.env" {
+		t.Fatalf("an env-file names the place; got %v", container["env-file"])
+	}
+}
+
+func TestAStatedPathIsThePlacementAndStillAnswersByName(t *testing.T) {
+	m := placedModule()
+	// The adopted-machine case: data that must sit where the predecessor already put it.
+	m.Resources[0]["path"] = "/services/mssql/data/"
+	dirs := dirsFor(m, Rendering{})
+	if dirs["data"] != "/services/mssql/data" {
+		t.Fatalf("a stated path wins over the root, trimmed; got %q", dirs["data"])
+	}
+	container := shallowCopy(m.Resources[2])
+	if err := dirInto(container, dirs, m.Module); err != nil {
+		t.Fatal(err)
+	}
+	if container["volumes"].([]any)[0] != "/services/mssql/data:/data" {
+		t.Fatalf("references follow the placement; got %v", container["volumes"])
+	}
+}
+
+func TestFillingForOneNodeLeaksIntoNoOther(t *testing.T) {
+	m := placedModule()
+	first := shallowCopy(m.Resources[2])
+	if err := dirInto(first, dirsFor(m, Rendering{DataRoot: "/first"}), m.Module); err != nil {
+		t.Fatal(err)
+	}
+	second := shallowCopy(m.Resources[2])
+	if err := dirInto(second, dirsFor(m, Rendering{DataRoot: "/second"}), m.Module); err != nil {
+		t.Fatal(err)
+	}
+	if got := second["volumes"].([]any)[0]; got != "/second/photos/data:/data" {
+		t.Fatalf("the second composition must see the manifest, not the first fill; got %v", got)
+	}
+	if m.Resources[2]["volumes"].([]any)[0] != "${dir:data}:/data" {
+		t.Fatalf("the manifest itself stays a template; got %v", m.Resources[2]["volumes"])
+	}
+}
+
+func TestAReferenceToNoDirectoryRefusesAtTheManifest(t *testing.T) {
+	m := placedModule()
+	m.Resources[2]["volumes"] = []any{"${dir:date}:/data"} // a typo, the likely shape
+	problems := m.unknownDirRefs()
+	if len(problems) != 1 || !strings.Contains(problems[0], `${dir:date}`) {
+		t.Fatalf("a reference naming no directory is a manifest problem; got %v", problems)
+	}
+	if got := placedModule().unknownDirRefs(); len(got) != 0 {
+		t.Fatalf("a correct definition has none; got %v", got)
+	}
+}
+
+func TestAReferenceToNoDirectoryRefusesAtCompositionToo(t *testing.T) {
+	m := placedModule()
+	container := shallowCopy(m.Resources[2])
+	container["env"] = map[string]any{"DATA": "${dir:date}"}
+	err := dirInto(container, dirsFor(m, Rendering{}), m.Module)
+	if err == nil || !strings.Contains(err.Error(), `"date"`) || !strings.Contains(err.Error(), `"data"`) {
+		t.Fatalf("the refusal names the mistake and what exists; got %v", err)
+	}
+}
+
+func shallowCopy(resource map[string]any) map[string]any {
+	copied := map[string]any{}
+	for k, v := range resource {
+		copied[k] = v
+	}
+	return copied
+}