Merge remote-tracking branch 'origin/release-3.8' into merge-3.8.1-to-main

Tweak RW2 change for consistency with older lines.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

CHANGELOG.md

@@ -2,12 +2,15 @@
 
 ## main / unreleased
 
-* [FEATURE] Templates: Add urlQueryEscape to template functions. #17403
 * [BUGFIX] TSDB: Register `prometheus_tsdb_sample_ooo_delta` metric properly. #17477
 
+## 3.8.1 / 2025-12-16
+
+* [BUGFIX] remote: Fix Remote Write receiver, so it does not send wrong response headers for v1 flow and cause Prometheus senders to emit false partial error log and metrics. #17683
+
 ## 3.8.0 / 2025-11-28
 
-* [CHANGE] Remote-write 2 (receiving): Update to [2.0-rc.4 spec](https://github.com/prometheus/docs/blob/60c24e450010df38cfcb4f65df874f6f9b26dbcb/docs/specs/prw/remote_write_spec_2_0.md). "created timestamp" (CT) is now called "start timestamp" (ST). #17411
+* [CHANGE] Remote-write: Update receiving to [2.0-rc.4 spec](https://github.com/prometheus/docs/blob/60c24e450010df38cfcb4f65df874f6f9b26dbcb/docs/specs/prw/remote_write_spec_2_0.md). "created timestamp" (CT) is now called "start timestamp" (ST). #17411
 * [CHANGE] TSDB: Native Histogram Custom Bounds with a NaN threshold are now rejected. #17287
 * [FEATURE] OAuth2: support jwt-bearer grant-type (RFC7523 3.1). #17592
 * [FEATURE] Dockerfile: Add OpenContainers spec labels to Dockerfile. #16483

VERSION

@@ -1 +1 @@
-3.8.0
+3.8.1

storage/remote/client.go

@@ -301,6 +301,9 @@ func (c *Client) Store(ctx context.Context, req []byte, attempt int) (WriteRespo
 		_ = httpResp.Body.Close()
 	}()
 
+	// NOTE(bwplotka): Only PRW2 spec defines response HTTP headers. However, spec does not block
+	// PRW1 from sending them too for reliability. Support this case.
+	//
 	// TODO(bwplotka): Pass logger and emit debug on error?
 	// Parsing error means there were some response header values we can't parse,
 	// we can continue handling.

storage/remote/write_handler.go

@@ -96,6 +96,10 @@ func isHistogramValidationError(err error) bool {
 }
 
 // Store implements remoteapi.writeStorage interface.
+// TODO(bwplotka): Improve remoteapi.Store API. Right now it's confusing if PRWv1 flows should use WriteResponse or not.
+// If it's not filled, it will be "confirmed zero" which caused partial error reporting on client side in the past.
+// Temporary fix was done to only care about WriteResponse stats for PRW2 (see https://github.com/prometheus/client_golang/pull/1927
+// but better approach would be to only confirm if explicit stats were injected.
 func (h *writeHandler) Store(r *http.Request, msgType remoteapi.WriteMessageType) (*remoteapi.WriteResponse, error) {
 	// Store receives request with decompressed content in body.
 	body, err := io.ReadAll(r.Body)

storage/remote/write_handler_test.go

@@ -1608,3 +1608,74 @@ func TestHistogramsReduction(t *testing.T) {
 		})
 	}
 }
+
+// Regression test for https://github.com/prometheus/prometheus/issues/17659
+func TestRemoteWriteHandler_ResponseStats(t *testing.T) {
+	payloadV1, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil, "snappy")
+	require.NoError(t, err)
+	payloadV2, _, _, err := buildV2WriteRequest(nil, writeV2RequestFixture.Timeseries, writeV2RequestFixture.Symbols, nil, nil, nil, "snappy")
+	require.NoError(t, err)
+
+	for _, tt := range []struct {
+		msgType            remoteapi.WriteMessageType
+		payload            []byte
+		forceInjectHeaders bool
+		expectHeaders      bool
+	}{
+		{
+			msgType: remoteapi.WriteV1MessageType,
+			payload: payloadV1,
+		},
+		{
+			msgType:            remoteapi.WriteV1MessageType,
+			payload:            payloadV1,
+			forceInjectHeaders: true,
+			expectHeaders:      true,
+		},
+		{
+			msgType:       remoteapi.WriteV2MessageType,
+			payload:       payloadV2,
+			expectHeaders: true,
+		},
+	} {
+		t.Run(fmt.Sprintf("msg=%v/force-inject-headers=%v", tt.msgType, tt.forceInjectHeaders), func(t *testing.T) {
+			// Setup server side.
+			appendable := &mockAppendable{}
+			handler := NewWriteHandler(
+				promslog.NewNopLogger(),
+				nil,
+				appendable,
+				[]remoteapi.WriteMessageType{remoteapi.WriteV1MessageType, remoteapi.WriteV2MessageType},
+				false,
+				false,
+				false,
+			)
+
+			if tt.forceInjectHeaders {
+				base := handler
+				handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					// Inject response header. This simulates PRWv1 server that uses PRWv2 response headers
+					// for confirmation of samples. This is not against spec and we support it.
+					w.Header().Set(rw20WrittenSamplesHeader, "2")
+
+					base.ServeHTTP(w, r)
+				})
+			}
+
+			srv := httptest.NewServer(handler)
+
+			// Send message and do the parse response flow.
+			c := &Client{Client: srv.Client(), urlString: srv.URL, timeout: 5 * time.Minute, writeProtoMsg: tt.msgType}
+
+			stats, err := c.Store(t.Context(), tt.payload, 0)
+			require.NoError(t, err)
+
+			if tt.expectHeaders {
+				require.True(t, stats.Confirmed)
+				require.Equal(t, len(appendable.samples), stats.Samples)
+			} else {
+				require.False(t, stats.Confirmed)
+			}
+		})
+	}
+}

web/ui/mantine-ui/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@prometheus-io/mantine-ui",
   "private": true,
-  "version": "0.308.0",
+  "version": "0.308.1",
   "type": "module",
   "scripts": {
     "start": "vite",
@@ -28,7 +28,7 @@
     "@microsoft/fetch-event-source": "^2.0.1",
     "@nexucis/fuzzy": "^0.5.1",
     "@nexucis/kvsearch": "^0.9.1",
-    "@prometheus-io/codemirror-promql": "0.308.0",
+    "@prometheus-io/codemirror-promql": "0.308.1",
     "@reduxjs/toolkit": "^2.10.1",
     "@tabler/icons-react": "^3.35.0",
     "@tanstack/react-query": "^5.90.7",

web/ui/module/codemirror-promql/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prometheus-io/codemirror-promql",
-  "version": "0.308.0",
+  "version": "0.308.1",
   "description": "a CodeMirror mode for the PromQL language",
   "types": "dist/esm/index.d.ts",
   "module": "dist/esm/index.js",
@@ -29,7 +29,7 @@
   },
   "homepage": "https://github.com/prometheus/prometheus/blob/main/web/ui/module/codemirror-promql/README.md",
   "dependencies": {
-    "@prometheus-io/lezer-promql": "0.308.0",
+    "@prometheus-io/lezer-promql": "0.308.1",
     "lru-cache": "^11.2.2"
   },
   "devDependencies": {

web/ui/module/lezer-promql/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prometheus-io/lezer-promql",
-  "version": "0.308.0",
+  "version": "0.308.1",
   "description": "lezer-based PromQL grammar",
   "main": "dist/index.cjs",
   "type": "module",

web/ui/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "prometheus-io",
-  "version": "0.308.0",
+  "version": "0.308.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "prometheus-io",
-      "version": "0.308.0",
+      "version": "0.308.1",
       "workspaces": [
         "mantine-ui",
         "module/*"

web/ui/package.json

@@ -1,7 +1,7 @@
 {
   "name": "prometheus-io",
   "description": "Monorepo for the Prometheus UI",
-  "version": "0.308.0",
+  "version": "0.308.1",
   "private": true,
   "scripts": {
     "build": "bash build_ui.sh --all",