From 9a187e02e45caa73520291047cee5d9d05b55a06 Mon Sep 17 00:00:00 2001
From: Yevgeniy Miretskiy <yevgeniy@cockroachlabs.com>
Date: Sat, 30 Oct 2021 08:31:47 -0400
Subject: [PATCH] changefeedccl: Remove metrics scope library.

Remove metrics scope library since it has been moved under changefeedccl.

Note: this is a move only refactoring, but it is structured as 2 changes
(one to add new files, and one to remove cdcutils files) so that it can
be easily backported.

Release Notes: None
---
 pkg/ccl/changefeedccl/cdcutils/BUILD.bazel    | 11 +--
 .../changefeedccl/cdcutils/metrics_scope.go   | 77 -------------------
 .../cdcutils/metrics_scope_test.go            | 57 --------------
 3 files changed, 2 insertions(+), 143 deletions(-)
 delete mode 100644 pkg/ccl/changefeedccl/cdcutils/metrics_scope.go
 delete mode 100644 pkg/ccl/changefeedccl/cdcutils/metrics_scope_test.go

diff --git a/pkg/ccl/changefeedccl/cdcutils/BUILD.bazel b/pkg/ccl/changefeedccl/cdcutils/BUILD.bazel
index a9dfffd76a83..993c43479b4e 100644
--- a/pkg/ccl/changefeedccl/cdcutils/BUILD.bazel
+++ b/pkg/ccl/changefeedccl/cdcutils/BUILD.bazel
@@ -2,10 +2,7 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "cdcutils",
-    srcs = [
-        "metrics_scope.go",
-        "throttle.go",
-    ],
+    srcs = ["throttle.go"],
     importpath = "github.com/cockroachdb/cockroach/pkg/ccl/changefeedccl/cdcutils",
     visibility = ["//visibility:public"],
     deps = [
@@ -21,17 +18,13 @@ go_library(
 
 go_test(
     name = "cdcutils_test",
-    srcs = [
-        "metrics_scope_test.go",
-        "throttle_test.go",
-    ],
+    srcs = ["throttle_test.go"],
     embed = [":cdcutils"],
     deps = [
         "//pkg/ccl/changefeedccl/changefeedbase",
         "//pkg/settings/cluster",
         "//pkg/util/leaktest",
         "//pkg/util/log",
-        "//pkg/util/metric",
         "@com_github_stretchr_testify//require",
     ],
 )
diff --git a/pkg/ccl/changefeedccl/cdcutils/metrics_scope.go b/pkg/ccl/changefeedccl/cdcutils/metrics_scope.go
deleted file mode 100644
index a69430dbe54a..000000000000
--- a/pkg/ccl/changefeedccl/cdcutils/metrics_scope.go
+++ /dev/null
@@ -1,77 +0,0 @@
-// Copyright 2021 The Cockroach Authors.
-//
-// Licensed as a CockroachDB Enterprise file under the Cockroach Community
-// License (the "License"); you may not use this file except in compliance with
-// the License. You may obtain a copy of the License at
-//
-//     https://github.com/cockroachdb/cockroach/blob/master/licenses/CCL.txt
-
-package cdcutils
-
-import (
-	"fmt"
-
-	"github.com/cockroachdb/cockroach/pkg/util/metric"
-)
-
-// maxSLIScopes is a static limit on the number of SLI scopes -- that is the number
-// of SLI metrics we will keep track of.
-// The limit is static due to metric.Registry limitations.
-const maxSLIScopes = 8
-
-// SLIMetrics is the list of SLI related metrics for changefeeds.
-type SLIMetrics struct {
-	ErrorRetries *metric.Counter
-	// TODO(yevgeniy): Add more SLI related metrics.
-}
-
-// MetricStruct implements metric.Struct interface
-func (*SLIMetrics) MetricStruct() {}
-
-func makeSLIMetrics(prefix string) *SLIMetrics {
-	withPrefix := func(meta metric.Metadata) metric.Metadata {
-		meta.Name = fmt.Sprintf("%s.%s", prefix, meta.Name)
-		return meta
-	}
-
-	return &SLIMetrics{
-		ErrorRetries: metric.NewCounter(withPrefix(metric.Metadata{
-			Name:        "error_retries",
-			Help:        "Total retryable errors encountered this SLI",
-			Measurement: "Errors",
-			Unit:        metric.Unit_COUNT,
-		})),
-	}
-}
-
-// SLIScopes represents a set of SLI related metrics for a particular "scope".
-type SLIScopes struct {
-	Scopes [maxSLIScopes]*SLIMetrics // Exported so that we can register w/ metrics registry.
-	names  map[string]*SLIMetrics
-}
-
-// MetricStruct implements metric.Struct interface
-func (*SLIScopes) MetricStruct() {}
-
-// CreateSLIScopes creates changefeed specific SLI scope: a metric.Struct containing
-// SLI specific metrics for each scope.
-// The scopes are statically named "tier<number>", and each metric name
-// contained in SLIMetrics will be prefixed by "changefeed.tier<number" prefix.
-func CreateSLIScopes() *SLIScopes {
-	scope := &SLIScopes{
-		names: make(map[string]*SLIMetrics, maxSLIScopes),
-	}
-
-	for i := 0; i < maxSLIScopes; i++ {
-		scopeName := fmt.Sprintf("tier%d", i)
-		scope.Scopes[i] = makeSLIMetrics(fmt.Sprintf("changefeed.%s", scopeName))
-		scope.names[scopeName] = scope.Scopes[i]
-	}
-	return scope
-}
-
-// GetSLIMetrics returns a metric.Struct associated with the specified scope, or nil
-// of no such scope exists.
-func (s *SLIScopes) GetSLIMetrics(scopeName string) *SLIMetrics {
-	return s.names[scopeName]
-}
diff --git a/pkg/ccl/changefeedccl/cdcutils/metrics_scope_test.go b/pkg/ccl/changefeedccl/cdcutils/metrics_scope_test.go
deleted file mode 100644
index c88513c1ce21..000000000000
--- a/pkg/ccl/changefeedccl/cdcutils/metrics_scope_test.go
+++ /dev/null
@@ -1,57 +0,0 @@
-// Copyright 2021 The Cockroach Authors.
-//
-// Licensed as a CockroachDB Enterprise file under the Cockroach Community
-// License (the "License"); you may not use this file except in compliance with
-// the License. You may obtain a copy of the License at
-//
-//     https://github.com/cockroachdb/cockroach/blob/master/licenses/CCL.txt
-
-package cdcutils
-
-import (
-	"fmt"
-	"testing"
-
-	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
-	"github.com/cockroachdb/cockroach/pkg/util/log"
-	"github.com/cockroachdb/cockroach/pkg/util/metric"
-	"github.com/stretchr/testify/require"
-)
-
-func TestMetricScope(t *testing.T) {
-	defer leaktest.AfterTest(t)()
-	defer log.Scope(t).Close(t)
-
-	scope := CreateSLIScopes()
-	require.NotNil(t, scope)
-
-	sliMetricNames := []string{
-		"error_retries",
-	}
-
-	expectedMetrics := make(map[string]struct{})
-	expectScopedMetrics := func(scope string) {
-		for _, n := range sliMetricNames {
-			expectedMetrics[fmt.Sprintf("changefeed.%s.%s", scope, n)] = struct{}{}
-		}
-	}
-
-	for i := 0; i < maxSLIScopes; i++ {
-		scopeName := fmt.Sprintf("tier%d", i)
-		require.NotNil(t, scope.GetSLIMetrics(scopeName))
-		expectScopedMetrics(scopeName)
-	}
-
-	require.Nil(t, scope.GetSLIMetrics("does not exist"))
-	require.Nil(t, scope.GetSLIMetrics(fmt.Sprintf("tier%d", maxSLIScopes+1)))
-
-	registry := metric.NewRegistry()
-	registry.AddMetricStruct(scope)
-	registry.Each(func(name string, _ interface{}) {
-		_, exists := expectedMetrics[name]
-		require.True(t, exists)
-		delete(expectedMetrics, name)
-	})
-	require.Equal(t, 0, len(expectedMetrics),
-		"remaining metrics: %s", expectedMetrics)
-}