fix: a required promoted claim is never sent to a warm peer; the Python SDK asks for the promoted template

sandboxd/server/server.go

@@ -378,7 +378,7 @@ func (s *Server) redirectClaim(ctx context.Context, w http.ResponseWriter, req t
 	if s.placer == nil || req.NoRedirect {
 		return false
 	}
-	if s.writeRedirect(w, s.placer.Candidates(hash)) {
+	if !req.RequirePromoted && s.writeRedirect(w, s.placer.Candidates(hash)) {
 		return true
 	}
 	owners := s.templateOwners(s.placer.TemplateOwners, hash, tenant)

sandboxd/server/server_test.go

@@ -1725,6 +1725,36 @@ func TestForeignTemplateGossipNeverEscalates(t *testing.T) {
 	}
 }
 
+func TestARequiredPromotedClaimIsNeverSentToAWarmPeer(t *testing.T) {
+	for _, tt := range []struct {
+		name       string
+		require    bool
+		wantStatus int
+		wantWarm   bool
+	}{
+		{"a plain claim follows the warm peer", false, http.StatusOK, true},
+		{"a required promoted claim answers 404 rather than a warm peer", true, http.StatusNotFound, false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			mgr := &fakeManager{claim: func(context.Context, types.PoolKey, time.Duration) (*types.Sandbox, error) {
+				return nil, pool.ErrUnknownTemplate
+			}}
+			srv := New("sekret", nil, "node-a:7777", mgr, &fakeDialer{}, &fakePlacer{addrs: []string{"warm:7777"}}, nil, nil, nil)
+			ts := httptest.NewServer(srv.Handler())
+			t.Cleanup(func() { ts.Close(); srv.CloseRelays() })
+
+			body, _ := json.Marshal(types.ClaimRequest{Template: "ns/app", RequirePromoted: tt.require})
+			resp := postJSON(t, ts.URL+"/v1/claim", "sekret", string(body))
+			defer resp.Body.Close()
+			var cr types.ClaimResponse
+			_ = json.UnmarshalRead(resp.Body, &cr)
+			if resp.StatusCode != tt.wantStatus || (len(cr.Redirect) > 0) != tt.wantWarm {
+				t.Errorf("status=%d redirect=%v, want %d and warm redirect %v", resp.StatusCode, cr.Redirect, tt.wantStatus, tt.wantWarm)
+			}
+		})
+	}
+}
+
 func TestAPlainClaimRequiringAPromotedTemplateNeverColdBoots(t *testing.T) {
 	for _, tt := range []struct {
 		name         string

sdk/python/cocoonsandbox/template.py

@@ -36,6 +36,7 @@ def new(
         from .client import _claim_body
 
         claim = _claim_body(self.name, self.net, self.size, ttl_seconds, volumes, mount)
+        claim["require_promoted"] = True
         if volumes:
             return self._client._claim_from(self._addr, claim, deadline=deadline)
         claim["no_redirect"] = True

sdk/python/tests/test_client.py

@@ -131,6 +131,14 @@ def test_claim_keeps_mounting_by_default(node):
     assert "volumes_attach_only" not in seen[0]
 
 
+def test_template_claim_asks_for_the_promoted_template(node):
+    seen = recording_claim({"id": "sb_9", "token": "tok"})
+    Template(Client(node), node, "task:v1", "none", "small").new()
+    assert seen == [
+        {"template": "task:v1", "net": "none", "size": "small", "no_redirect": True, "require_promoted": True}
+    ]
+
+
 def test_template_claim_sends_volumes(node):
     seen = recording_claim(
         {"id": "sb_2", "token": "tok", "volumes": [{"name": "imagenet", "mount": "/datasets/imagenet"}]}
@@ -144,6 +152,7 @@ def test_template_claim_sends_volumes(node):
             "net": "none",
             "size": "small",
             "volumes": [{"name": "imagenet", "mount": "/datasets/imagenet"}],
+            "require_promoted": True,
         }
     ]
     assert sb.volumes == [{"name": "imagenet", "mount": "/datasets/imagenet"}]