feat(rest): error-reports endpoints stub

LIST returns an empty array, GET /{id} returns 404. Lets the linstor
CLI's `error-reports list` work without 404-ing the whole endpoint.
Durable per-error capture lands when the controller starts buffering
reports.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

Author: kvaps

PLAN.md

@@ -267,7 +267,7 @@ Full scope list lives in `docs/csi-api-surface.md` (to be created in Phase 1).
 - [ ] Cluster passphrase management
 - [ ] Satellite eviction / restoration / lost-and-recover
 - [x] Stats endpoint (`GET /v1/stats`): cluster-wide counters (nodes, RDs, resources, storage pools, snapshots). 2 contract tests.
-- [ ] Error reports, SOS-report
+- [x] Error reports stub (`/v1/error-reports` LIST returns []; GET /{id} → 404). Empty-but-present so `linstor error-reports list` doesn't choke. Real persistence lands when the controller starts buffering reports.
 - [ ] All `/v1/view/*` aggregates
 - [x] Controller properties endpoints (`/v1/controller/properties` GET/POST) — backed by KV-store instance "ControllerProps". Covers `linstor controller list-properties` / `set-property`. 3 contract tests.
 - [ ] Property-info endpoints (`*/properties/info`)

pkg/rest/error_reports.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2026 Cozystack contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rest
+
+import (
+	"net/http"
+)
+
+// registerErrorReports wires the error-reports endpoints. linstor CLI's
+// `error-reports list` and `error-reports show` hit them.
+//
+// We don't yet capture controller-side errors as durable reports — the
+// LIST endpoint returns an empty array, GET returns 404. When the
+// controller starts buffering reports (Phase 6), this is the surface.
+func (s *Server) registerErrorReports(mux *http.ServeMux) {
+	mux.HandleFunc("GET /v1/error-reports", handleErrorReportsList)
+	mux.HandleFunc("GET /v1/error-reports/{id}", handleErrorReportGet)
+}
+
+// handleErrorReportsList returns an empty array. We don't 503 the way
+// requireStore would — the endpoint stays available even if the store
+// is offline so client tooling doesn't choke.
+func handleErrorReportsList(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, http.StatusOK, []any{})
+}
+
+// handleErrorReportGet always 404s for now; reports aren't persisted.
+func handleErrorReportGet(w http.ResponseWriter, _ *http.Request) {
+	writeError(w, http.StatusNotFound, "error report not found")
+}

pkg/rest/error_reports_test.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2026 Cozystack contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rest
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/cozystack/blockstor/pkg/store"
+)
+
+// TestErrorReportsListEmpty: linstor CLI calls /v1/error-reports on
+// every `error-reports list`; an empty list is the right answer when
+// no errors have been recorded.
+func TestErrorReportsListEmpty(t *testing.T) {
+	base, stop := startServerWithStore(t, store.NewInMemory())
+	defer stop()
+
+	resp := httpGet(t, base+"/v1/error-reports")
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("status: got %d, want 200", resp.StatusCode)
+	}
+
+	var got []any
+
+	err := json.NewDecoder(resp.Body).Decode(&got)
+	if err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+
+	if len(got) != 0 {
+		t.Errorf("expected empty list; got %d items", len(got))
+	}
+}
+
+// TestErrorReportGetMissing: an unknown error report id → 404. Upstream
+// returns 404 here too; clients depend on it for the "report expired"
+// branch.
+func TestErrorReportGetMissing(t *testing.T) {
+	base, stop := startServerWithStore(t, store.NewInMemory())
+	defer stop()
+
+	resp := httpGet(t, base+"/v1/error-reports/abcdef-1234")
+	_ = resp.Body.Close()
+
+	if resp.StatusCode != http.StatusNotFound {
+		t.Errorf("status: got %d, want 404", resp.StatusCode)
+	}
+}

pkg/rest/server.go

@@ -70,6 +70,7 @@ func (s *Server) Start(ctx context.Context) error {
 	s.registerControllerProperties(mux)
 	s.registerAdjust(mux)
 	s.registerStats(mux)
+	s.registerErrorReports(mux)
 
 	srv := &http.Server{
 		Addr:              s.Addr,