metric: embed source file in Metadata for CODEOWNERS resolution

Previously, metric ownership was determined by a separate
gen-metric-owners tool that scanned Go source files via AST to find
metric.Metadata definitions, mapped each to its owning team via
CODEOWNERS, and produced a metric_owners.yaml file. This file was
checked into the tree but had no Bazel genrule, and required a
bespoke step in both ./dev generate and check-generated-code CI.

This commit eliminates that pipeline by embedding source file
information directly in metric.Metadata at definition time. A new
source_file proto field is populated by metric.NewMetadata(), which
captures the caller's file via runtime.Caller. At generation time,
cockroach gen metric-list resolves ownership by calling
codeowners.Match on each metric's source file — no separate AST
scanning needed.

To enforce adoption, a new metadatanew nogo analyzer flags bare
metric.Metadata{} composite literals that aren't wrapped in
NewMetadata(). The metric registry also logs a warning when metrics
are registered without a source file set.

Removed:
- pkg/cmd/gen-metric-owners and its Bazel target
- pkg/internal/metricscan/metric_owners.yaml and its go:embed wrapper
- The generateMetricOwners step from ./dev generate
- The bazel run //pkg/cmd/gen-metric-owners step from check-generated-code.sh
- The --metric-owners flag from cockroach gen metric-list

Epic: none

Release note: None
Co-Authored-By: roachdev-claude <roachdev-claude-bot@cockroachlabs.com>

Author: angles-n-daemons

BUILD.bazel

@@ -205,6 +205,7 @@ nogo(
         "//pkg/testutils/lint/passes/grpcstatuswithdetails",
         "//pkg/testutils/lint/passes/hash",
         "//pkg/testutils/lint/passes/leaktestcall",
+        "//pkg/testutils/lint/passes/metadatanew",
         "//pkg/testutils/lint/passes/nilness",
         "//pkg/testutils/lint/passes/nocopy",
         "//pkg/testutils/lint/passes/redactcheck",

build/bazelutil/nogo_config.json

@@ -1654,5 +1654,16 @@
             "external/": "exclude all third-party code for all analyzers",
             "pkg/sql/colexec/colexechash/hash\\.go$": "re-implements runtime.noescape for efficient hashing"
         }
+    },
+    "metadatanew": {
+        "exclude_files": {
+            "external/": "exclude all third-party code",
+            ".*\\.pb\\.go$": "generated code",
+            ".*\\.pb\\.gw\\.go$": "generated code",
+            "pkg/.*\\.eg\\.go$": "generated code",
+            "pkg/.*_generated\\.go$": "generated code",
+            "pkg/util/metric/.*\\.go$": "metric package internal usage is allowed",
+            "pkg/testutils/": "test utilities may construct Metadata for testing"
+        }
     }
 }

build/github/check-generated-code.sh

@@ -61,10 +61,6 @@ if grep TODO DEPS.bzl; then
 fi
 check_workspace_clean "Run \`./dev generate bazel\` to fix this error."
 
-# Run gen-metric-owners to ensure metric_owners.yaml is up to date
-# before //pkg/gen regenerates metrics.yaml from it.
-bazel run //pkg/cmd/gen-metric-owners $ENGFLOW_ARGS -- -out="$(pwd)/pkg/internal/metricscan/metric_owners.yaml"
-
 # Run `bazel run //pkg/gen` and ensure nothing changes. This ensures
 # generated documentation and checked-in go code are up to date.
 bazel run //pkg/gen $ENGFLOW_ARGS

docs/generated/metrics/BUILD.bazel

@@ -1,10 +1,7 @@
 genrule(
     name = "metrics",
-    srcs = [
-        "//pkg/internal/metricscan:metric_owners.yaml",
-    ],
     outs = ["metrics.yaml"],
-    cmd = "$(location //pkg/cmd/cockroach-short) gen metric-list --logtostderr=NONE --metric-owners=$(location //pkg/internal/metricscan:metric_owners.yaml) > $@",
+    cmd = "$(location //pkg/cmd/cockroach-short) gen metric-list --logtostderr=NONE > $@",
     tools = ["//pkg/cmd/cockroach-short"],
     visibility = [
         ":__pkg__",

pkg/BUILD.bazel

@@ -1208,8 +1208,6 @@ GO_TARGETS = [
     "//pkg/cmd/flaky-test-notifier:flaky-test-notifier_lib",
     "//pkg/cmd/fuzz:fuzz",
     "//pkg/cmd/fuzz:fuzz_lib",
-    "//pkg/cmd/gen-metric-owners:gen-metric-owners",
-    "//pkg/cmd/gen-metric-owners:gen-metric-owners_lib",
     "//pkg/cmd/generate-acceptance-tests:generate-acceptance-tests",
     "//pkg/cmd/generate-acceptance-tests:generate-acceptance-tests_lib",
     "//pkg/cmd/generate-ash-inventory:generate-ash-inventory",
@@ -2761,6 +2759,7 @@ GO_TARGETS = [
     "//pkg/testutils/lint/passes/hash:hash_test",
     "//pkg/testutils/lint/passes/leaktestcall:leaktestcall",
     "//pkg/testutils/lint/passes/leaktestcall:leaktestcall_test",
+    "//pkg/testutils/lint/passes/metadatanew:metadatanew",
     "//pkg/testutils/lint/passes/nilness:nilness",
     "//pkg/testutils/lint/passes/nilness:nilness_test",
     "//pkg/testutils/lint/passes/nocopy:nocopy",

pkg/backup/backup_metrics.go

@@ -22,12 +22,12 @@ func (b BackupMetrics) MetricStruct() {}
 // MakeBackupMetrics instantiates the metrics for backup.
 func MakeBackupMetrics(time.Duration) metric.Struct {
 	m := &BackupMetrics{
-		LastKMSInaccessibleErrorTime: metric.NewGauge(metric.Metadata{
+		LastKMSInaccessibleErrorTime: metric.NewGauge(metric.NewMetadata(metric.Metadata{
 			Name:        "backup.last-failed-time.kms-inaccessible",
 			Help:        "The unix timestamp of the most recent failure of backup due to errKMSInaccessible by a backup specified as maintaining this metric",
 			Measurement: "Jobs",
 			Unit:        metric.Unit_TIMESTAMP_SEC,
-		}),
+		})),
 	}
 	return m
 }

pkg/backup/schedule_exec.go

@@ -606,7 +606,7 @@ func init() {
 				metrics: backupMetrics{
 					ExecutorMetrics:    &m,
 					ExecutorPTSMetrics: &pm,
-					RpoMetric: metric.NewGauge(metric.Metadata{
+					RpoMetric: metric.NewGauge(metric.NewMetadata(metric.Metadata{
 						Name: "schedules.BACKUP.last-completed-time",
 						Help: crstrings.UnwrapText(`
 							The unix timestamp of the most recently completed backup by a
@@ -629,16 +629,16 @@ func init() {
 							For example with a backup frequency of 60 minutes, monitor
 							time() - max_across_nodes(max_over_time(schedules_BACKUP_last_completed_time, 60min)).
 						`),
-					}),
-					RpoTenantMetric: metric.NewExportedGaugeVec(metric.Metadata{
+					})),
+					RpoTenantMetric: metric.NewExportedGaugeVec(metric.NewMetadata(metric.Metadata{
 						Name: "schedules.BACKUP.last-completed-time-by-virtual_cluster",
 						Help: crstrings.UnwrapText(`
 							The unix timestamp of the most recently completed host scheduled
 							backup by virtual cluster specified as maintaining this metric
 						`),
 						Measurement: "Jobs",
 						Unit:        metric.Unit_TIMESTAMP_SEC,
-					}, []string{"tenant_id"}),
+					}), []string{"tenant_id"}),
 				},
 			}, nil
 		})

pkg/backup/schedule_exec_test.go

@@ -27,8 +27,8 @@ func TestBackupSucceededUpdatesMetrics(t *testing.T) {
 	ctx := context.Background()
 	executor := &scheduledBackupExecutor{
 		metrics: backupMetrics{
-			RpoMetric:       metric.NewGauge(metric.Metadata{}),
-			RpoTenantMetric: metric.NewExportedGaugeVec(metric.Metadata{}, []string{"tenant_id"}),
+			RpoMetric:       metric.NewGauge(metric.NewMetadata(metric.Metadata{})),
+			RpoTenantMetric: metric.NewExportedGaugeVec(metric.NewMetadata(metric.Metadata{}), []string{"tenant_id"}),
 		},
 	}
 
@@ -63,8 +63,8 @@ func TestBackupSucceededUpdatesMetrics(t *testing.T) {
 		// Use a fresh executor to ensure RpoMetric starts at zero.
 		freshExecutor := &scheduledBackupExecutor{
 			metrics: backupMetrics{
-				RpoMetric:       metric.NewGauge(metric.Metadata{}),
-				RpoTenantMetric: metric.NewExportedGaugeVec(metric.Metadata{}, []string{"tenant_id"}),
+				RpoMetric:       metric.NewGauge(metric.NewMetadata(metric.Metadata{})),
+				RpoTenantMetric: metric.NewExportedGaugeVec(metric.NewMetadata(metric.Metadata{}), []string{"tenant_id"}),
 			},
 		}
 		schedule := createSchedule(t, true)

pkg/ccl/changefeedccl/cdcutils/throttle.go

@@ -145,13 +145,13 @@ type Metrics struct {
 // MakeMetrics constructs a Metrics struct with the provided histogram window.
 func MakeMetrics(histogramWindow time.Duration) Metrics {
 	makeMetric := func(n string) metric.Metadata {
-		return metric.Metadata{
+		return metric.NewMetadata(metric.Metadata{
 			Name:        fmt.Sprintf("changefeed.%s.messages_pushback_nanos", n),
 			Help:        fmt.Sprintf("Total time spent throttled for %s quota", n),
 			Measurement: "Nanoseconds",
 			Unit:        metric.Unit_NANOSECONDS,
 			Category:    metric.Metadata_CHANGEFEEDS,
-		}
+		})
 	}
 
 	return Metrics{

pkg/ccl/changefeedccl/checkpoint/metrics.go

@@ -12,37 +12,37 @@ import (
 )
 
 var (
-	metaCreateNanos = metric.Metadata{
+	metaCreateNanos = metric.NewMetadata(metric.Metadata{
 		Name:        "changefeed.checkpoint.create_nanos",
 		Help:        "Time it takes to create a changefeed checkpoint",
 		Unit:        metric.Unit_NANOSECONDS,
 		Measurement: "Nanoseconds",
 		Category:    metric.Metadata_CHANGEFEEDS,
-	}
+	})
 
-	metaTotalBytes = metric.Metadata{
+	metaTotalBytes = metric.NewMetadata(metric.Metadata{
 		Name:        "changefeed.checkpoint.total_bytes",
 		Help:        "Total size of a changefeed checkpoint",
 		Unit:        metric.Unit_BYTES,
 		Measurement: "Bytes",
 		Category:    metric.Metadata_CHANGEFEEDS,
-	}
+	})
 
-	metaTimestampCount = metric.Metadata{
+	metaTimestampCount = metric.NewMetadata(metric.Metadata{
 		Name:        "changefeed.checkpoint.timestamp_count",
 		Help:        "Number of unique timestamps in a changefeed checkpoint",
 		Unit:        metric.Unit_COUNT,
 		Measurement: "Timestamps",
 		Category:    metric.Metadata_CHANGEFEEDS,
-	}
+	})
 
-	metaSpanCount = metric.Metadata{
+	metaSpanCount = metric.NewMetadata(metric.Metadata{
 		Name:        "changefeed.checkpoint.span_count",
 		Help:        "Number of spans in a changefeed checkpoint",
 		Unit:        metric.Unit_COUNT,
 		Measurement: "Spans",
 		Category:    metric.Metadata_CHANGEFEEDS,
-	}
+	})
 )
 
 type AggMetrics struct {