Attach context

Guardfile

@@ -9,6 +9,8 @@ group :sinatra do
           all_on_start: true,
           cmd: "RACK_ENV=#{env} bundle exec appraisal sinatra14 rspec" do
       watch(%r{^spec/integration/sinatra_spec.rb$})
+      watch('lib/loga/context_manager.rb')
+      watch('spec/loga/context_manager_spec.rb')
     end
   end
 end
@@ -34,6 +36,8 @@ group :rails do
         end
 
         watch(%r{^spec/integration/rails/.+_spec\.rb$})
+        watch('lib/loga/context_manager.rb')
+        watch('spec/loga/context_manager_spec.rb')
       end
     end
   end
@@ -50,12 +54,16 @@ group :sidekiq do
         'spec/loga/sidekiq_spec.rb',
       ]
     end
+    watch('lib/loga/context_manager.rb')
+    watch('spec/loga/context_manager_spec.rb')
   end
 end
 
 group :unit do
   guard :rspec, cmd: 'bundle exec appraisal unit rspec' do
     watch(%r{^spec/unit/.+_spec\.rb$})
     watch(%r{^lib/(.+)\.rb$}) { |m| "spec/unit/#{m[1]}_spec.rb" }
+    watch('lib/loga/context_manager.rb')
+    watch('spec/loga/context_manager_spec.rb')
   end
 end

lib/loga.rb

@@ -9,32 +9,53 @@
 require 'loga/rack/request_id'
 require 'loga/railtie' if defined?(Rails)
 require 'loga/sidekiq'
+require 'loga/context_manager'
 
 module Loga
   ConfigurationError = Class.new(StandardError)
 
-  def self.configuration
-    unless @configuration
-      raise ConfigurationError,
-            'Loga has not been configured. Configure with Loga.configure(options)'
+  class << self
+    def configuration
+      unless @configuration
+        raise ConfigurationError,
+              'Loga has not been configured. Configure with Loga.configure(options)'
+      end
+
+      @configuration
     end
 
-    @configuration
-  end
+    def configure(options, framework_options = {})
+      raise ConfigurationError, 'Loga has already been configured' if @configuration
 
-  def self.configure(options, framework_options = {})
-    raise ConfigurationError, 'Loga has already been configured' if @configuration
+      @configuration ||= Configuration.new(options, framework_options)
 
-    @configuration ||= Configuration.new(options, framework_options)
+      Loga::Sidekiq.configure_logging
+    end
 
-    Loga::Sidekiq.configure_logging
-  end
+    def logger
+      configuration.logger
+    end
 
-  def self.logger
-    configuration.logger
-  end
+    def reset
+      @configuration = nil
+    end
 
-  def self.reset
-    @configuration = nil
+    def attach_context(payload)
+      current_context.attach_context(payload)
+    end
+
+    def clear_context
+      current_context.clear
+    end
+
+    def retrieve_context
+      current_context.retrieve_context
+    end
+
+    private
+
+    def current_context
+      ContextManager.current
+    end
   end
 end

lib/loga/configuration.rb

@@ -14,44 +14,42 @@ class Configuration
       Sinatra::NotFound
     ].freeze
 
-    attr_accessor :device, :filter_exceptions, :filter_parameters,
-                  :host, :level, :service_version, :sync, :tags, :hide_pii
-    attr_reader :logger, :format, :service_name
+    attr_reader :device, :filter_exceptions, :filter_parameters, :format, :hide_pii,
+                :host, :level, :service_name, :service_version, :sync, :tags
 
-    # rubocop:disable Metrics/MethodLength
     def initialize(user_options = {}, framework_options = {})
       options = default_options.merge(framework_options)
                                .merge(environment_options)
                                .merge(user_options)
 
-      self.device            = options[:device]
-      self.filter_exceptions = options[:filter_exceptions]
-      self.filter_parameters = options[:filter_parameters]
-      self.format            = options[:format]
-      self.host              = options[:host]
-      self.level             = options[:level]
-      self.service_name      = options[:service_name]
-      self.service_version   = options[:service_version] || ServiceVersionStrategies.call
-      self.sync              = options[:sync]
-      self.tags              = options[:tags]
-      self.hide_pii          = options[:hide_pii]
+      @device            = options[:device]
+      @filter_exceptions = options[:filter_exceptions]
+      @filter_parameters = options[:filter_parameters]
+      @format            = options[:format].to_s.to_sym
+      @hide_pii          = options[:hide_pii]
+      @host              = options[:host]
+      @level             = options[:level]
+      @service_name      = options[:service_name].to_s.strip
+      @service_version   = options[:service_version] || ServiceVersionStrategies.call
+      @sync              = options[:sync]
+      @tags              = options[:tags]
 
       validate
-
-      @logger = initialize_logger
     end
-    # rubocop:enable Metrics/MethodLength
 
-    def format=(name)
-      @format = name.to_s.to_sym
+    def structured?
+      format == :gelf
     end
 
-    def service_name=(name)
-      @service_name = name.to_s.strip
-    end
+    def logger
+      @logger ||= begin
+        device.sync          = sync
+        new_logger           = Logger.new(device)
+        new_logger.formatter = assign_formatter
+        new_logger.level     = constantized_log_level
 
-    def structured?
-      format == :gelf
+        TaggedLogging.new(new_logger)
+      end
     end
 
     private
@@ -79,14 +77,6 @@ def environment_options
       { format: ENV['LOGA_FORMAT'].presence }.reject { |_, v| v.nil? }
     end
 
-    def initialize_logger
-      device.sync      = sync
-      logger           = Logger.new(device)
-      logger.formatter = assign_formatter
-      logger.level     = constantized_log_level
-      TaggedLogging.new(logger)
-    end
-
     def constantized_log_level
       Logger.const_get(level.to_s.upcase)
     end
@@ -98,15 +88,13 @@ def hostname
     end
 
     def assign_formatter
-      if format == :gelf
-        Formatters::GELFFormatter.new(
-          service_name:    service_name,
-          service_version: service_version,
-          host:            host,
-        )
-      else
-        Formatters::SimpleFormatter.new
-      end
+      return Formatters::SimpleFormatter.new if format != :gelf
+
+      Formatters::GELFFormatter.new(
+        service_name:    service_name,
+        service_version: service_version,
+        host:            host,
+      )
     end
   end
 end

lib/loga/context_manager.rb

@@ -0,0 +1,31 @@
+require 'thread'
+
+module Loga
+  class ContextManager
+    def self.current
+      Thread.current[:__loga_context_manager] ||= new
+    end
+
+    def initialize
+      @semaphore = Mutex.new
+
+      clear
+    end
+
+    def clear
+      @semaphore.synchronize do
+        @context = {}
+      end
+    end
+
+    def attach_context(payload)
+      @semaphore.synchronize do
+        @context.update(payload)
+      end
+    end
+
+    def retrieve_context
+      @semaphore.synchronize { @context }
+    end
+  end
+end

lib/loga/formatters/gelf_formatter.rb

@@ -48,12 +48,15 @@ def build_event(time, message)
 
         event.timestamp ||= time
         event.data ||= {}
-        event.data.tap do |hash|
-          hash.merge! compute_exception(event.exception)
-          hash.merge! compute_type(event.type)
+
+        event.data.tap do |data_hash|
+          data_hash.merge!(compute_exception(event.exception))
+          data_hash.merge!(compute_type(event.type))
           # Overwrite hash with Loga's additional fields
-          hash.merge! loga_additional_fields
+          data_hash.merge!(loga_additional_fields)
+          data_hash.merge!(Loga.retrieve_context)
         end
+
         event
       end
 

lib/loga/rack/logger.rb

@@ -43,7 +43,7 @@ def set_data
         data['request_ip'] = request.ip
         data['user_agent'] = request.user_agent
         data['controller'] = request.controller_action_name if request.controller_action_name
-        data['duration']   = duration_in_ms(started_at, Time.now)
+        data['duration']   = duration_in_ms(started_at)
       end
       # rubocop:enable Metrics/LineLength
 
@@ -55,6 +55,7 @@ def send_message
           timestamp:  started_at,
           type:       'request',
         )
+
         logger.public_send(compute_level, event)
       end
 

spec/fixtures/rails32.rb

@@ -49,6 +49,12 @@ def update
     @id = params[:id]
     render '/user'
   end
+
+  def attach_context
+    Loga.attach_context(animal: 'monkey')
+
+    render json: { hello: :world }
+  end
 end
 
 class FakeMailer < ActionMailer::Base
@@ -68,13 +74,36 @@ def basic_mail
   end
 end
 
+class FakeMailerWithContext < ActionMailer::Base
+  default from: 'notifications@example.com'
+
+  def self.send_email
+    Loga.attach_context(tshirt_size: 'XL')
+    Loga.attach_context(height: 155)
+    Loga.attach_context(weight: 122)
+
+    basic_mail.deliver
+  end
+
+  def basic_mail
+    mail(
+      to: 'user@example.com',
+      subject: 'Welcome to My Awesome Site',
+      body: 'Banana muffin',
+      content_type: 'text/html',
+    )
+  end
+end
+
 Dummy.routes.append do
   get 'ok'        => 'application#ok'
   get 'error'     => 'application#error'
   get 'show'      => 'application#show'
   post 'users'    => 'application#create'
   get 'new'       => 'application#new'
   put 'users/:id' => 'application#update'
+
+  get 'attach_context' => 'application#attach_context'
 end
 
 Dummy.initialize!

spec/fixtures/rails40.rb

@@ -49,6 +49,12 @@ def update
     @id = params[:id]
     render '/user'
   end
+
+  def attach_context
+    Loga.attach_context(animal: 'monkey')
+
+    render json: { hello: :world }
+  end
 end
 
 class FakeMailer < ActionMailer::Base
@@ -68,13 +74,36 @@ def basic_mail
   end
 end
 
+class FakeMailerWithContext < ActionMailer::Base
+  default from: 'notifications@example.com'
+
+  def self.send_email
+    Loga.attach_context(tshirt_size: 'XL')
+    Loga.attach_context(height: 155)
+    Loga.attach_context(weight: 122)
+
+    basic_mail.deliver
+  end
+
+  def basic_mail
+    mail(
+      to: 'user@example.com',
+      subject: 'Welcome to My Awesome Site',
+      body: 'Banana muffin',
+      content_type: 'text/html',
+    )
+  end
+end
+
 Dummy.routes.append do
   get 'ok'        => 'application#ok'
   get 'error'     => 'application#error'
   get 'show'      => 'application#show'
   post 'users'    => 'application#create'
   get 'new'       => 'application#new'
   put 'users/:id' => 'application#update'
+
+  get 'attach_context' => 'application#attach_context'
 end
 
 Dummy.initialize!