Context providers refactor

lib/twiglet/formatter.rb

@@ -11,12 +11,13 @@ def initialize(
       validator:,
       default_properties: {},
       context_provider: nil,
+      context_providers: [],
       now: -> { Time.now.utc }
     )
       @service_name = service_name
       @now = now
       @default_properties = default_properties
-      @context_provider = context_provider
+      @context_providers = context_provider ? [context_provider] : context_providers
       @validator = validator
 
       super()
@@ -45,7 +46,9 @@ def log(level:, message:)
         }
       }
 
-      context = @context_provider&.call || {}
+      context = @context_providers.reduce({}) do |c, context_provider|
+        c.deep_merge(context_provider.call)
+      end
 
       JSON.generate(
         base_message

lib/twiglet/logger.rb

@@ -33,7 +33,7 @@ def initialize(
       formatter = Twiglet::Formatter.new(
         service_name,
         default_properties: args.fetch(:default_properties, {}),
-        context_provider: args[:context_provider],
+        context_providers: Array(args[:context_provider] || args[:context_providers]),
         now: now,
         validator: @validator
       )
@@ -82,15 +82,12 @@ def with(default_properties)
     end
 
     def context_provider(&blk)
-      new_context_provider = blk
-      if @args[:context_provider]
-        new_context_provider = lambda do
-          @args[:context_provider].call.merge(blk.call)
-        end
-      end
+      new_context_providers = Array(@args[:context_providers])
+      new_context_providers << blk
+
       self.class.new(
         @service_name,
-        **@args.merge(context_provider: new_context_provider)
+        **@args.merge(context_providers: new_context_providers)
       )
     end
 

lib/twiglet/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Twiglet
-  VERSION = '3.10.0'
+  VERSION = '3.11.0'
 end

test/formatter_test.rb

@@ -58,4 +58,32 @@
     }
     assert_equal JSON.parse(msg), expected_log
   end
+
+  it 'merges the outputs of all context providers into the messages log' do
+    provider_1 = -> { { 'request' => { 'id' => '1234567890' } } }
+    provider_2 = -> { { 'request' => { 'type' => 'test' } } }
+    formatter = Twiglet::Formatter.new(
+      'petshop', now: @now, validator: Twiglet::Validator.new({}.to_json),
+                 context_providers: [provider_1, provider_2]
+    )
+    msg = formatter.call('warn', nil, nil, 'shop is running low on dog food')
+    expected_log = {
+      "ecs" => {
+        "version" => '1.5.0'
+      },
+      "@timestamp" => '2020-05-11T15:01:01.000Z',
+      "service" => {
+        "name" => 'petshop'
+      },
+      "log" => {
+        "level" => 'warn'
+      },
+      "message" => 'shop is running low on dog food',
+      "request" => {
+        'id' => '1234567890',
+        'type' => 'test'
+      }
+    }
+    assert_equal expected_log, JSON.parse(msg)
+  end
 end

test/logger_test.rb

@@ -189,9 +189,37 @@
     end
 
     it "should be able to add contextual information to events with the context_provider" do
-      purchase_logger = @logger.context_provider do
-        { 'context' => { 'id' => 'my-context-id' } }
-      end
+      provider = -> { { 'context' => { 'id' => 'my-context-id' } } }
+      purchase_logger = Twiglet::Logger.new(
+        'petshop',
+        now: @now,
+        output: @buffer,
+        context_provider: provider
+      )
+
+      # do stuff
+      purchase_logger.info(
+        {
+          message: 'customer bought a dog',
+          pet: { name: 'Barker', species: 'dog', breed: 'Bitsa' }
+        }
+      )
+
+      log = read_json @buffer
+
+      assert_equal 'customer bought a dog', log[:message]
+      assert_equal 'my-context-id', log[:context][:id]
+    end
+
+    it "should be able to add contextual information to events with multiple context providers" do
+      provider_1 = -> { { 'context' => { 'id' => 'my-context-id' } } }
+      provider_2 = -> { { 'context' => { 'type' => 'test' } } }
+      purchase_logger = Twiglet::Logger.new(
+        'petshop',
+        now: @now,
+        output: @buffer,
+        context_providers: [provider_1, provider_2]
+      )
 
       # do stuff
       purchase_logger.info(
@@ -205,6 +233,7 @@
 
       assert_equal 'customer bought a dog', log[:message]
       assert_equal 'my-context-id', log[:context][:id]
+      assert_equal 'test', log[:context][:type]
     end
 
     it "chaining .with and .context_provider is possible" do