0.9.0: Ability to add default tags only for a specific group (#19)

Author: liaden

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## 0.9.0 - 2021-05-07
+
+### Added
+
+- Ability to set global metric tags only for a specific group [#19](https://github.com/yabeda-rb/yabeda/pull/19) by [@liaden]
+
 ## 0.8.0 - 2020-08-21
 
 ### Added
@@ -99,3 +105,4 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 [@Envek]: https://github.com/Envek "Andrey Novikov"
 [@dsalahutdinov]: https://github.com/dsalahutdinov "Dmitry Salahutdinov"
 [@asusikov]: https://github.com/asusikov "Alexander Susikov"
+[@liaden]: https://github.com/liaden "Joel Johnson"

README.md

@@ -79,10 +79,14 @@ And then execute:
     end
     ```
 
-  5. _Optionally_ setup default tags that will be added to all metrics
+  5. _Optionally_ setup default tags for all appropriate metrics
      ```ruby
      Yabeda.configure do
+       # matches all metrics in all groups
        default_tag :rails_environment, 'production'
+
+       # matches all metrics in the :your_app group
+       default_tag :tag_name, 'override', group: :your_app
      end
 
      # You can redefine them for limited amount of time
@@ -91,8 +95,19 @@ And then execute:
      end
      ```
 
-  6. See the docs for the adapter you're using
-  7. Enjoy!
+     **Note**: any usage of `with_tags` **must** have all those tags defined on all metrics that are generated in the block.
+
+  6. _Optionally_ override default tags using precedence:
+
+     The tag precedence from high to low is:
+
+     * Manually specified tags
+     * Thread local tags (specified by `Yabeda.with_tags`)
+     * Group specific tags
+     * Global tags
+
+  7. See the docs for the adapter you're using
+  8. Enjoy!
 
 ## Available monitoring system adapters
 

lib/yabeda.rb

@@ -20,7 +20,9 @@ def metrics
 
     # @return [Hash<String, Yabeda::Group>] All registered metrics
     def groups
-      @groups ||= Concurrent::Hash.new
+      @groups ||= Concurrent::Hash.new.tap do |hash|
+        hash[nil] = Yabeda::GlobalGroup.new(nil)
+      end
     end
 
     # @return [Hash<String, Yabeda::BaseAdapter>] All loaded adapters
@@ -33,7 +35,7 @@ def collectors
       @collectors ||= Concurrent::Array.new
     end
 
-    # @return [Hash<Symbol, Symbol>] All added default tags
+    # @return [Hash<Symbol, Symbol>] All added global default tags
     def default_tags
       @default_tags ||= Concurrent::Hash.new
     end
@@ -86,14 +88,18 @@ def configure!
     # Forget all the configuration.
     # For testing purposes as it doesn't rollback changes in adapters.
     # @api private
+    # rubocop: disable Metrics/AbcSize
     def reset!
       default_tags.clear
       adapters.clear
-      groups.clear
-      metrics.clear
+      groups.each_key { |group| singleton_class.send(:remove_method, group) if group && respond_to?(group) }
+      @groups = nil
+      metrics.each_key { |metric| singleton_class.send(:remove_method, metric) if respond_to?(metric) }
+      @metrics = nil
       collectors.clear
       configurators.clear
       instance_variable_set(:@configured_by, nil)
     end
+    # rubocop: enable Metrics/AbcSize
   end
 end

lib/yabeda/counter.rb

@@ -4,7 +4,7 @@ module Yabeda
   # Growing-only counter
   class Counter < Metric
     def increment(tags, by: 1)
-      all_tags = ::Yabeda::Tags.build(tags)
+      all_tags = ::Yabeda::Tags.build(tags, group)
       values[all_tags] += by
       ::Yabeda.adapters.each do |_, adapter|
         adapter.perform_counter_increment!(self, all_tags, by)

lib/yabeda/dsl/class_methods.rb

@@ -5,6 +5,7 @@
 require "yabeda/gauge"
 require "yabeda/histogram"
 require "yabeda/group"
+require "yabeda/global_group"
 require "yabeda/dsl/metric_builder"
 
 module Yabeda
@@ -30,6 +31,7 @@ def collect(&block)
       # (like NewRelic) it is treated individually and has a special meaning.
       def group(group_name)
         @group = group_name
+        Yabeda.groups[@group] ||= Yabeda::Group.new(@group)
         return unless block_given?
 
         yield
@@ -58,24 +60,30 @@ def histogram(*args, **kwargs, &block)
       #
       # @param name [Symbol] Name of default tag
       # @param value [String] Value of default tag
-      def default_tag(name, value)
-        ::Yabeda.default_tags[name] = value
+      def default_tag(name, value, group: @group)
+        if group
+          Yabeda.groups[group] ||= Yabeda::Group.new(group)
+          Yabeda.groups[group].default_tag(name, value)
+        else
+          Yabeda.default_tags[name] = value
+        end
       end
 
       # Redefine default tags for a limited amount of time
       # @param tags Hash{Symbol=>#to_s}
       def with_tags(**tags)
-        Thread.current[:yabeda_temporary_tags] = tags
+        previous_temp_tags = temporary_tags
+        Thread.current[:yabeda_temporary_tags] = Thread.current[:yabeda_temporary_tags].merge(tags)
         yield
       ensure
-        Thread.current[:yabeda_temporary_tags] = {}
+        Thread.current[:yabeda_temporary_tags] = previous_temp_tags
       end
 
       # Get tags set by +with_tags+
       # @api private
       # @return Hash
       def temporary_tags
-        Thread.current[:yabeda_temporary_tags] || {}
+        Thread.current[:yabeda_temporary_tags] ||= {}
       end
 
       private
@@ -95,9 +103,10 @@ def register_group_for(metric)
         if group.nil?
           group = Group.new(metric.group)
           ::Yabeda.groups[metric.group] = group
-          ::Yabeda.define_singleton_method(metric.group) { group }
         end
 
+        ::Yabeda.define_singleton_method(metric.group) { group } unless ::Yabeda.respond_to?(metric.group)
+
         group.register_metric(metric)
       end
     end

lib/yabeda/gauge.rb

@@ -4,7 +4,7 @@ module Yabeda
   # Arbitrary value, can be changed in both sides
   class Gauge < Metric
     def set(tags, value)
-      all_tags = ::Yabeda::Tags.build(tags)
+      all_tags = ::Yabeda::Tags.build(tags, group)
       values[all_tags] = value
       ::Yabeda.adapters.each do |_, adapter|
         adapter.perform_gauge_set!(self, all_tags, value)

lib/yabeda/global_group.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "forwardable"
+require_relative "./group"
+
+module Yabeda
+  # Represents implicit global group
+  class GlobalGroup < Group
+    extend Forwardable
+
+    def_delegators ::Yabeda, :default_tags, :default_tag
+  end
+end

lib/yabeda/group.rb

@@ -9,6 +9,16 @@ class Group
 
     param :name
 
+    def default_tags
+      @default_tags ||= Concurrent::Hash.new
+      ::Yabeda.default_tags.merge(@default_tags)
+    end
+
+    def default_tag(key, value)
+      @default_tags ||= Concurrent::Hash.new
+      @default_tags[key] = value
+    end
+
     def register_metric(metric)
       define_singleton_method(metric.name) { metric }
     end

lib/yabeda/histogram.rb

@@ -7,7 +7,7 @@ class Histogram < Metric
     option :buckets
 
     def measure(tags, value)
-      all_tags = ::Yabeda::Tags.build(tags)
+      all_tags = ::Yabeda::Tags.build(tags, group)
       values[all_tags] = value
       ::Yabeda.adapters.each do |_, adapter|
         adapter.perform_histogram_measure!(self, all_tags, value)

lib/yabeda/metric.rb

@@ -17,15 +17,17 @@ class Metric
 
     # Returns the value for the given label set
     def get(labels = {})
-      values[::Yabeda::Tags.build(labels)]
+      values[::Yabeda::Tags.build(labels, group)]
     end
 
     def values
       @values ||= Concurrent::Hash.new
     end
 
+    # Returns allowed tags for metric (with account for global and group-level +default_tags+)
+    # @return Array<Symbol>
     def tags
-      (Yabeda.default_tags.keys + Array(super)).uniq
+      (Yabeda.groups[group].default_tags.keys + Array(super)).uniq
     end
   end
 end

lib/yabeda/tags.rb

@@ -3,8 +3,12 @@
 module Yabeda
   # Class to merge tags
   class Tags
-    def self.build(tags)
-      ::Yabeda.default_tags.merge(Yabeda.temporary_tags).merge(tags)
+    def self.build(tags, group_name = nil)
+      Yabeda.default_tags.dup.tap do |result|
+        result.merge!(Yabeda.groups[group_name].default_tags) if group_name
+        result.merge!(Yabeda.temporary_tags)
+        result.merge!(tags)
+      end
     end
   end
 end

lib/yabeda/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Yabeda
-  VERSION = "0.8.0"
+  VERSION = "0.9.0"
 end

spec/yabeda/counter_spec.rb

@@ -14,7 +14,7 @@
       counter :test_counter
     end
     Yabeda.configure!
-    allow(Yabeda::Tags).to receive(:build).with(tags).and_return(built_tags)
+    allow(Yabeda::Tags).to receive(:build).with(tags, anything).and_return(built_tags)
     ::Yabeda.register_adapter(:test_adapter, adapter)
   end
 

spec/yabeda/dsl/class_methods_spec.rb

@@ -1,24 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe Yabeda::DSL::ClassMethods do
-  after do
-    if Yabeda.instance_variable_defined?(:@groups)
-      Yabeda.instance_variable_get(:@groups).each_key do |group|
-        Yabeda.singleton_class.send(:remove_method, group)
-      end
-      Yabeda.remove_instance_variable(:@groups)
-    end
-
-    if Yabeda.instance_variable_defined?(:@metrics)
-      Yabeda.instance_variable_get(:@metrics).each_key do |metric|
-        Yabeda.singleton_class.send(:remove_method, metric)
-      end
-      Yabeda.remove_instance_variable(:@metrics)
-    end
-
-    ::Yabeda.default_tags.clear
-  end
-
   describe ".group" do
     context "without block" do
       before do
@@ -125,5 +107,40 @@
 
       it { is_expected.to eq(environment: "test") }
     end
+
+    context "with a specified group that does not exist" do
+      before do
+        Yabeda.configure { default_tag :environment, "test", group: :missing_group }
+        Yabeda.configure!
+      end
+
+      it "creates the group" do
+        expect(Yabeda.groups[:missing_group]).to be_a(Yabeda::Group)
+      end
+
+      it "defines the default tag" do
+        expect(Yabeda.groups[:missing_group].default_tags).to eq(environment: "test")
+      end
+    end
+
+    context "when specified group is defined after default_tag" do
+      before do
+        Yabeda.configure { default_tag :environment, "test", group: :missing_group }
+        Yabeda.configure do
+          group :missing_group
+          default_tag :key, "value"
+          gauge :test_gauge, comment: "..."
+        end
+        Yabeda.configure!
+      end
+
+      it "defines all the tags" do
+        expect(Yabeda.groups[:missing_group].default_tags).to eq(environment: "test", key: "value")
+      end
+
+      it "test_gauge has all the tags defined" do
+        expect(Yabeda.missing_group.test_gauge.tags).to eq(%i[environment key])
+      end
+    end
   end
 end

spec/yabeda/gauge_spec.rb

@@ -14,7 +14,7 @@
       gauge :test_gauge
     end
     Yabeda.configure!
-    allow(Yabeda::Tags).to receive(:build).with(tags).and_return(built_tags)
+    allow(Yabeda::Tags).to receive(:build).with(tags, anything).and_return(built_tags)
     ::Yabeda.register_adapter(:test_adapter, adapter)
   end
 

spec/yabeda/group_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+RSpec.describe Yabeda::Group do
+  let(:name) { nil }
+
+  let(:group) { described_class.new(name) }
+
+  before do
+    Yabeda.groups[name] = group
+  end
+
+  after { Yabeda.reset! }
+
+  describe "default tags" do
+    context "when on the top level group" do
+      it "is an empty by default" do
+        expect(group.default_tags).to be_empty
+      end
+    end
+
+    context "when within a named group" do
+      let(:name) { :group1 }
+
+      it "includes top level default_tags" do
+        Yabeda.default_tag :tag, "default"
+        expect(group.default_tags).to eq(tag: "default")
+      end
+
+      it "overrides top level default_tags" do
+        Yabeda.default_tag :tag, "default"
+        group.default_tag :tag, "overridden"
+        expect(Yabeda.groups[nil].default_tags).to eq(tag: "default")
+        expect(group.default_tags).to eq(tag: "overridden")
+      end
+    end
+  end
+end

spec/yabeda/histogram_spec.rb

@@ -14,7 +14,7 @@
       histogram :test_histogram, buckets: [1, 10, 100]
     end
     Yabeda.configure!
-    allow(Yabeda::Tags).to receive(:build).with(tags).and_return(built_tags)
+    allow(Yabeda::Tags).to receive(:build).with(tags, anything).and_return(built_tags)
     ::Yabeda.register_adapter(:test_adapter, adapter)
   end