Merge pull request 'A process runs its own bundle's binary, written ./name (hq ADR 0193)' (#81) from feat/a-process-runs-its-own-binary into main

internal/apply/process.go

@@ -214,7 +214,7 @@ func unitFor(r *declaration.Process) string {
 	if r.User != "" {
 		fmt.Fprintf(&b, "User=%s\n", r.User)
 	}
-	fmt.Fprintf(&b, "ExecStart=%s\n", strings.Join(r.Run, " "))
+	fmt.Fprintf(&b, "ExecStart=%s\n", strings.Join(runFrom(r), " "))
 	if r.Schedule != "" {
 		// Started by its timer and expected to finish. Restarting it would have it run
 		// continuously between fires, which is the opposite of a schedule.
@@ -346,3 +346,15 @@ func removeProcess(ctx context.Context, a store.Applied, run Runner) (string, st
 	}
 	return "removed", "stopped; its unit and its bundle removed — the mesh's own code", nil
 }
+
+// runFrom is the command as the unit runs it. **A command written `./name` is that file in the
+// process's own unpacked bundle** (novox/hq ADR 0193): a bundle compiled to a binary runs itself,
+// and only the host knows where it unpacked it, while the service manager takes an absolute path or
+// a name it finds on its own search path — never one relative to the working directory.
+func runFrom(r *declaration.Process) []string {
+	run := append([]string(nil), r.Run...)
+	if len(run) > 0 && strings.HasPrefix(run[0], "./") {
+		run[0] = filepath.Join(daemonRoot, r.Name, strings.TrimPrefix(run[0], "./"))
+	}
+	return run
+}

internal/apply/process_test.go

@@ -313,3 +313,16 @@ func TestAProcessAppliedAgainIsUnchangedAndNotRestarted(t *testing.T) {
 		t.Errorf("third apply: %+v, want unchanged", o)
 	}
 }
+
+// novox/hq ADR 0193: a bundle compiled to a binary runs itself — `./name` is that file in the
+// process's own unpacked bundle, made absolute because the service manager takes nothing relative.
+func TestAProcessRunsItsOwnBundlesBinary(t *testing.T) {
+	unit := unitFor(&declaration.Process{Name: "node-tools", Run: []string{"./node-tools", "serve"}})
+	if !strings.Contains(unit, "ExecStart="+filepath.Join(daemonRoot, "node-tools", "node-tools")+" serve\n") {
+		t.Errorf("the binary is not run from its bundle:\n%s", unit)
+	}
+	other := unitFor(&declaration.Process{Name: "x", Run: []string{"node", "src/main.js"}})
+	if !strings.Contains(other, "ExecStart=node src/main.js\n") {
+		t.Errorf("a command found on the path was changed:\n%s", other)
+	}
+}