[PRW-2.0] (part2) Moved to latest basic negotiation & spec semantics.

Spec: prometheus/docs#2462

Supersedes #13968

Signed-off-by: bwplotka <bwplotka@gmail.com>

# Conflicts:
#	config/config.go
#	docs/configuration/configuration.md
#	storage/remote/queue_manager_test.go
#	storage/remote/write.go
#	web/api/v1/api.go

Author: bwplotka

cmd/promtool/metrics.go

@@ -116,7 +116,7 @@ func parseAndPushMetrics(client *remote.Client, data []byte, labels map[string]s
 
 	// Encode the request body into snappy encoding.
 	compressed := snappy.Encode(nil, raw)
-	err = client.Store(context.Background(), compressed, 0, remote.Version1, "snappy")
+	err = client.Store(context.Background(), compressed, 0)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "  FAILED:", err)
 		return false

config/config.go

@@ -1026,9 +1026,6 @@ func CheckTargetAddress(address model.LabelValue) error {
 	return nil
 }
 
-// TODO(bwplotka): Remove in the next PRs (review split PR for readability).
-type RemoteWriteFormat int64
-
 // RemoteWriteProtoMsg represents the known protobuf message for the remote write
 // 1.0 and 2.0 specs.
 type RemoteWriteProtoMsg string
@@ -1054,7 +1051,7 @@ func (m RemoteWriteProtoMsgs) Strings() []string {
 }
 
 func (m RemoteWriteProtoMsgs) String() string {
-	return strings.Join(m.Strings(), ",")
+	return strings.Join(m.Strings(), ", ")
 }
 
 var (

docs/configuration/configuration.md

@@ -3557,7 +3557,7 @@ url: <string>
 # Before changing this value, consult with your remote storage provider (or test) what message it supports.
 # Read more on https://prometheus.io/docs/specs/remote_write_spec_2_0/#io-prometheus-write-v2-request
 [ protobuf_message: <prometheus.WriteRequest | io.prometheus.write.v2.Request > | default = prometheus.WriteRequest ]
-
+  
 # Timeout for requests to the remote write endpoint.
 [ remote_timeout: <duration> | default = 30s ]
 

prompb/io/prometheus/write/v2/symbols.go

@@ -0,0 +1,83 @@
+// Copyright 2024 Prometheus Team
+// 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 writev2
+
+import "github.com/prometheus/prometheus/model/labels"
+
+// SymbolsTable implements table for easy symbol use.
+type SymbolsTable struct {
+	strings    []string
+	symbolsMap map[string]uint32
+}
+
+// NewSymbolTable returns a symbol table.
+func NewSymbolTable() SymbolsTable {
+	return SymbolsTable{
+		// Empty string is required as a first element.
+		symbolsMap: map[string]uint32{"": 0},
+		strings:    []string{""},
+	}
+}
+
+// Symbolize adds (if not added before) a string to the symbols table,
+// while returning its reference number.
+func (t *SymbolsTable) Symbolize(str string) uint32 {
+	if ref, ok := t.symbolsMap[str]; ok {
+		return ref
+	}
+	ref := uint32(len(t.strings))
+	t.strings = append(t.strings, str)
+	t.symbolsMap[str] = ref
+	return ref
+}
+
+// SymbolizeLabels symbolize Prometheus labels.
+func (t *SymbolsTable) SymbolizeLabels(lbls labels.Labels, buf []uint32) []uint32 {
+	result := buf[:0]
+	lbls.Range(func(l labels.Label) {
+		off := t.Symbolize(l.Name)
+		result = append(result, off)
+		off = t.Symbolize(l.Value)
+		result = append(result, off)
+	})
+	return result
+}
+
+// Symbols returns computes symbols table to put in e.g. Request.Symbols.
+// As per spec, order does not matter.
+func (t *SymbolsTable) Symbols() []string {
+	return t.strings
+}
+
+// Reset clears symbols table.
+func (t *SymbolsTable) Reset() {
+	// NOTE: Make sure to keep empty symbol.
+	t.strings = t.strings[:1]
+	for k := range t.symbolsMap {
+		if k == "" {
+			continue
+		}
+		delete(t.symbolsMap, k)
+	}
+}
+
+// DesymbolizeLabels decodes label references, with given symbols to labels.
+func DesymbolizeLabels(labelRefs []uint32, symbols []string) labels.Labels {
+	b := labels.NewScratchBuilder(len(labelRefs))
+	for i := 0; i < len(labelRefs); i += 2 {
+		b.Add(symbols[labelRefs[i]], symbols[labelRefs[i+1]])
+	}
+	b.Sort()
+	return b.Labels()
+}

prompb/io/prometheus/write/v2/symbols_test.go

@@ -0,0 +1,59 @@
+// Copyright 2024 Prometheus Team
+// 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 writev2
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/model/labels"
+)
+
+func TestSymbolsTable(t *testing.T) {
+	s := NewSymbolTable()
+	require.Equal(t, []string{""}, s.Symbols(), "required empty reference does not exist")
+	require.Equal(t, uint32(0), s.Symbolize(""))
+	require.Equal(t, []string{""}, s.Symbols())
+
+	require.Equal(t, uint32(1), s.Symbolize("abc"))
+	require.Equal(t, []string{"", "abc"}, s.Symbols())
+
+	require.Equal(t, uint32(2), s.Symbolize("__name__"))
+	require.Equal(t, []string{"", "abc", "__name__"}, s.Symbols())
+
+	require.Equal(t, uint32(3), s.Symbolize("foo"))
+	require.Equal(t, []string{"", "abc", "__name__", "foo"}, s.Symbols())
+
+	s.Reset()
+	require.Equal(t, []string{""}, s.Symbols(), "required empty reference does not exist")
+	require.Equal(t, uint32(0), s.Symbolize(""))
+
+	require.Equal(t, uint32(1), s.Symbolize("__name__"))
+	require.Equal(t, []string{"", "__name__"}, s.Symbols())
+
+	require.Equal(t, uint32(2), s.Symbolize("abc"))
+	require.Equal(t, []string{"", "__name__", "abc"}, s.Symbols())
+
+	ls := labels.FromStrings("__name__", "qwer", "zxcv", "1234")
+	encoded := s.SymbolizeLabels(ls, nil)
+	require.Equal(t, []uint32{1, 3, 4, 5}, encoded)
+	decoded := DesymbolizeLabels(encoded, s.Symbols())
+	require.Equal(t, ls, decoded)
+
+	// Different buf.
+	ls = labels.FromStrings("__name__", "qwer", "zxcv2222", "1234")
+	encoded = s.SymbolizeLabels(ls, []uint32{1, 3, 4, 5})
+	require.Equal(t, []uint32{1, 3, 6, 5}, encoded)
+}