Replace all chain namespaces with labels

api/metrics/prefix_gatherer.go

@@ -4,8 +4,8 @@
 package metrics
 
 import (
+	"errors"
 	"fmt"
-	"slices"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"google.golang.org/protobuf/proto"
@@ -15,7 +15,11 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )
 
-var _ MultiGatherer = (*prefixGatherer)(nil)
+var (
+	_ MultiGatherer = (*prefixGatherer)(nil)
+
+	errOverlappingNamespaces = errors.New("prefix could create overlapping namespaces")
+)
 
 // NewPrefixGatherer returns a new MultiGatherer that merges metrics by adding a
 // prefix to their names.
@@ -31,12 +35,14 @@ func (g *prefixGatherer) Register(prefix string, gatherer prometheus.Gatherer) e
 	g.lock.Lock()
 	defer g.lock.Unlock()
 
-	// TODO: Restrict prefixes to avoid potential conflicts
-	if slices.Contains(g.names, prefix) {
-		return fmt.Errorf("%w: %q",
-			errDuplicateGatherer,
-			prefix,
-		)
+	for _, existingPrefix := range g.names {
+		if eitherIsPrefix(prefix, existingPrefix) {
+			return fmt.Errorf("%w: %q conflicts with %q",
+				errOverlappingNamespaces,
+				prefix,
+				existingPrefix,
+			)
+		}
 	}
 
 	g.names = append(g.names, prefix)
@@ -64,3 +70,19 @@ func (g *prefixedGatherer) Gather() ([]*dto.MetricFamily, error) {
 	}
 	return metricFamilies, err
 }
+
+// eitherIsPrefix returns true if either [a] is a prefix of [b] or [b] is a
+// prefix of [a].
+//
+// This function accounts for the usage of the namespace boundary, so "hello" is
+// not considered a prefix of "helloworld". However, "hello" is considered a
+// prefix of "hello_world".
+func eitherIsPrefix(a, b string) bool {
+	if len(a) > len(b) {
+		a, b = b, a
+	}
+	return a == b[:len(a)] && // a is a prefix of b
+		(len(a) == 0 || // a is empty
+			len(a) == len(b) || // a is equal to b
+			b[len(a)] == metric.NamespaceSeparatorByte) // a ends at a namespace boundary of b
+}

api/metrics/prefix_gatherer_test.go

@@ -134,7 +134,7 @@ func TestPrefixGatherer_Register(t *testing.T) {
 			prefixGatherer:         firstPrefixGatherer(),
 			prefix:                 firstPrefixedGatherer.prefix,
 			gatherer:               secondPrefixedGatherer.gatherer,
-			expectedErr:            errDuplicateGatherer,
+			expectedErr:            errOverlappingNamespaces,
 			expectedPrefixGatherer: firstPrefixGatherer(),
 		},
 	}
@@ -148,3 +148,57 @@ func TestPrefixGatherer_Register(t *testing.T) {
 		})
 	}
 }
+
+func TestEitherIsPrefix(t *testing.T) {
+	tests := []struct {
+		name     string
+		a        string
+		b        string
+		expected bool
+	}{
+		{
+			name:     "empty strings",
+			a:        "",
+			b:        "",
+			expected: true,
+		},
+		{
+			name:     "an empty string",
+			a:        "",
+			b:        "hello",
+			expected: true,
+		},
+		{
+			name:     "same strings",
+			a:        "x",
+			b:        "x",
+			expected: true,
+		},
+		{
+			name:     "different strings",
+			a:        "x",
+			b:        "y",
+			expected: false,
+		},
+		{
+			name:     "splits namespace",
+			a:        "hello",
+			b:        "hello_world",
+			expected: true,
+		},
+		{
+			name:     "is prefix before separator",
+			a:        "hello",
+			b:        "helloworld",
+			expected: false,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			require := require.New(t)
+
+			require.Equal(test.expected, eitherIsPrefix(test.a, test.b))
+			require.Equal(test.expected, eitherIsPrefix(test.b, test.a))
+		})
+	}
+}

chains/linearizable_vm.go

@@ -6,7 +6,6 @@ package chains
 import (
 	"context"
 
-	"github.com/ava-labs/avalanchego/api/metrics"
 	"github.com/ava-labs/avalanchego/database"
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/snow"
@@ -29,7 +28,6 @@ type initializeOnLinearizeVM struct {
 	vmToInitialize common.VM
 	vmToLinearize  *linearizeOnInitializeVM
 
-	registerer   metrics.MultiGatherer
 	ctx          *snow.Context
 	db           database.Database
 	genesisBytes []byte
@@ -42,7 +40,6 @@ type initializeOnLinearizeVM struct {
 
 func (vm *initializeOnLinearizeVM) Linearize(ctx context.Context, stopVertexID ids.ID) error {
 	vm.vmToLinearize.stopVertexID = stopVertexID
-	vm.ctx.Metrics = vm.registerer
 	return vm.vmToInitialize.Initialize(
 		ctx,
 		vm.ctx,