The catalogue checks its placement files: each reads as its node's, and no port, address, hub or seat is placed twice (issue 1126, ADR 0549 §1, ADR 0555)

checks/placement/go.mod

@@ -0,0 +1,5 @@
+module checks/placement
+
+go 1.26.0
+
+require git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026171759-a431746c0e8c

checks/placement/go.sum

@@ -0,0 +1,14 @@
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026171759-a431746c0e8c h1:zaSfYTJd03b0pF29QTZ6G5ajfjOXRXjHIpOiGu/niHA=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026171759-a431746c0e8c/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+github.com/klauspost/compress v1.20.0 h1:a3C1ke2ohxFymNlb2HWAHjDeKCI90scRskErZkR0ezA=
+github.com/klauspost/compress v1.20.0/go.mod h1:LUdAzn7YLVvxLpc7y3V1m40wESHTgc1422pwwBSKYuI=
+github.com/nats-io/nats.go v1.54.0 h1:vsXoOxjHp/GmPUN+EcI7uOf/uB+iAP+kEsAFNQN0yzA=
+github.com/nats-io/nats.go v1.54.0/go.mod h1:y+DZoD1oBOYfZTU681eTUiUjI0vbqYGixNVFHcjHJ0k=
+github.com/nats-io/nkeys v0.4.16 h1:rd5oAuLOb8mnAycB0xleuEBNS1pVVnN0fv/FF34Eypg=
+github.com/nats-io/nkeys v0.4.16/go.mod h1:llLgWoI0o4z/Q57q2R1kHfmocyhGV6VG/U18Glg1Afs=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+golang.org/x/crypto v0.57.0 h1:3ZVCjf8Ggz7zneR/EHRVx68Ctf+2pmIMP2UFhh9cC6M=
+golang.org/x/crypto v0.57.0/go.mod h1:Fdz0i5U6CoizGwLda9DttjSk6qlZo25zYNtR+ycvuZA=
+golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
+golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=

checks/placement/main.go

@@ -0,0 +1,80 @@
+// Command placement is the catalogue's check of its placement files (novox/hq ADR 0549 §1, ADR 0555; issue 1126): every
+// `placement/<node>.json` reads as a placement of the node its name says, and the files together are refused, every
+// finding named at once, for two modules of one node on one host port, a pin, binding or holding naming a provider not
+// placed where it says, a seat held once for the mesh held twice, two nodes with one address on the private network, or
+// more than one hub (mesh-sdk delivery.CheckPlacements).
+//
+// A module the catalogue does not hold and a node not enrolled are the composition check's to refuse: placement names
+// modules of every repository the indexer reads and the nodes the mesh enrolled, neither of which this tree holds.
+//
+//	go run . <catalogue root>
+//
+// Exits 1 on a finding.
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// Check reads every placement file under root and answers each finding; none is a catalogue whose placement holds. A
+// catalogue with no placement directory has none to check.
+func Check(root string) ([]string, error) {
+	dir := filepath.Join(root, delivery.PlacementDir)
+	entries, err := os.ReadDir(dir)
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var found []string
+	placements := map[string]delivery.Placement{}
+	for _, e := range entries {
+		rel := delivery.PlacementDir + "/" + e.Name()
+		node, ok := delivery.PlacementFileNode(rel)
+		if e.IsDir() || !ok {
+			found = append(found, fmt.Sprintf("%s is not a placement file: the directory holds only <node>.json, one per node", rel))
+			continue
+		}
+		raw, err := os.ReadFile(filepath.Join(dir, e.Name()))
+		if err != nil {
+			return nil, err
+		}
+		p, err := delivery.DecodePlacement(raw)
+		if err != nil {
+			found = append(found, fmt.Sprintf("%s does not read as a placement: %v", rel, err))
+			continue
+		}
+		if p.Revision != "" {
+			found = append(found, fmt.Sprintf("%s names a revision, which only the indexer writes into the key", rel))
+		}
+		placements[node] = p
+	}
+	all := func(string) bool { return true }
+	found = append(found, delivery.CheckPlacements(placements, all, all)...)
+	sort.Strings(found)
+	return found, nil
+}
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Fprintln(os.Stderr, "usage: placement <catalogue root>")
+		os.Exit(2)
+	}
+	found, err := Check(os.Args[1])
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+	for _, f := range found {
+		fmt.Println(f)
+	}
+	if len(found) > 0 {
+		os.Exit(1)
+	}
+}

checks/placement/main_test.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// The catalogue's placement files as the merge check reads them (ADR 0549 §1, ADR 0555): the real tree holds every
+// rule, and a tree that breaks them is refused with every finding named at once.
+func TestPlacementFiles(t *testing.T) {
+	found, err := Check("../..")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, f := range found {
+		t.Errorf("%s (novox/hq ADR 0549 §1)", f)
+	}
+
+	root := t.TempDir()
+	write := func(name, body string) {
+		t.Helper()
+		if err := os.MkdirAll(filepath.Join(root, "placement"), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(root, "placement", name), []byte(body), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if found, err := Check(root); err != nil || len(found) != 0 {
+		t.Fatalf("a catalogue with no placement directory: %v, %v", found, err)
+	}
+	write("ace.json", `{"v":1,"node":"ace","decided":{"hub":true,"address":"10.77.0.1"},"modules":[{"module":"a","ports":{"80":8080}},{"module":"b","ports":{"81":8080}}]}`)
+	write("g14.json", `{"v":1,"node":"g14","decided":{"hub":true,"address":"10.77.0.1"},"modules":[{"module":"c","bindings":{"pg":{"node":"ace","module":"pg"}}}]}`)
+	write("novox.json", `{"v":1,"node":"shanks","modules":[]}`)
+	write("bad.json", `{"v":1,"node":"bad","modules":{}}`)
+	write("dated.json", `{"v":1,"node":"dated","revision":"abc","modules":[]}`)
+	write("notes.md", "x")
+	found, err = Check(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{"a and b are both published on host port 8080", "bound to ace/pg", "both have the address 10.77.0.1",
+		"ace, g14 are each placed as it", "placement file of novox names the node", "bad.json does not read", "dated.json names a revision",
+		"notes.md is not a placement file"} {
+		hit := false
+		for _, f := range found {
+			hit = hit || strings.Contains(f, want)
+		}
+		if !hit {
+			t.Errorf("no finding says %q; found %v", want, found)
+		}
+	}
+}

checks/placement/reads-outside

@@ -0,0 +1 @@
+These tests read files outside this directory (the whole catalogue, the repository, or its root files): mesh-build-go never keeps this package's verdict (issue 1935).