Implements AWS SigV4 for the HTTP output plugin.

fluentd.gemspec

@@ -56,4 +56,7 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency("oj", [">= 2.14", "< 4"])
   gem.add_development_dependency("async", "~> 1.23")
   gem.add_development_dependency("async-http", ">= 0.50.0")
+  gem.add_development_dependency("aws-sigv4", ["~> 1.8"])
+  gem.add_development_dependency("aws-sdk-core", ["~> 3.191"])
+  gem.add_development_dependency("rexml", ["~> 3.2"])
 end

lib/fluent/plugin/out_http.rb

@@ -87,11 +87,17 @@ class RetryableResponse < StandardError; end
 
     config_section :auth, required: false, multi: false do
       desc 'The method for HTTP authentication'
-      config_param :method, :enum, list: [:basic], default: :basic
+      config_param :method, :enum, list: [:basic, :aws_sigv4], default: :basic
       desc 'The username for basic authentication'
       config_param :username, :string, default: nil
       desc 'The password for basic authentication'
       config_param :password, :string, default: nil, secret: true
+      desc 'The AWS service to authenticate against'
+      config_param :aws_service, :string, default: nil
+      desc 'The AWS region to use when authenticating'
+      config_param :aws_region, :string, default: nil
+      desc 'The AWS role ARN to assume when authenticating'
+      config_param :aws_role_arn, :string, default: nil
     end
 
     def initialize
@@ -121,6 +127,36 @@ def configure(conf)
         end
         define_singleton_method(:format, method(:format_json_array))
       end
+
+      if @auth and @auth.method == :aws_sigv4
+        begin
+          require 'aws-sigv4'
+          require 'aws-sdk-core'
+        rescue LoadError
+          raise Fluent::ConfigError, "The aws-sdk-core and aws-sigv4 gems are required for aws_sigv4 auth. Run: gem install aws-sdk-core -v '~> 3.191'"
+        end
+
+        raise Fluent::ConfigError, "aws_service is required for aws_sigv4 auth" unless @auth.aws_service != nil
+        raise Fluent::ConfigError, "aws_region is required for aws_sigv4 auth" unless @auth.aws_region != nil
+
+        if @auth.aws_role_arn == nil
+          aws_credentials = Aws::CredentialProviderChain.new.resolve
+        else
+          aws_credentials = Aws::AssumeRoleCredentials.new(
+            client: Aws::STS::Client.new(
+              region: @auth.aws_region
+            ),
+            role_arn: @auth.aws_role_arn,
+            role_session_name: "fluentd"
+          )
+        end
+
+        @aws_signer = Aws::Sigv4::Signer.new(
+          service: @auth.aws_service,
+          region: @auth.aws_region,
+          credentials_provider: aws_credentials
+        )
+      end
     end
 
     def multi_workers_ready?
@@ -215,7 +251,7 @@ def parse_endpoint(chunk)
       URI.parse(endpoint)
     end
 
-    def set_headers(req, chunk)
+    def set_headers(req, uri, chunk)
       if @headers
         @headers.each do |k, v|
           req[k] = v
@@ -229,21 +265,44 @@ def set_headers(req, chunk)
       req['Content-Type'] = @content_type
     end
 
+    def set_auth(req, uri)
+      return unless @auth
+
+      if @auth.method == :basic
+        req.basic_auth(@auth.username, @auth.password)
+      elsif @auth.method == :aws_sigv4
+        signature = @aws_signer.sign_request(
+          http_method: req.method,
+          url: uri.request_uri,
+          headers: {
+            'Content-Type' => @content_type,
+            'Host' => uri.host
+          },
+          body: req.body
+        )
+        req.add_field('x-amz-date', signature.headers['x-amz-date'])
+        req.add_field('x-amz-security-token', signature.headers['x-amz-security-token'])
+        req.add_field('x-amz-content-sha256', signature.headers['x-amz-content-sha256'])
+        req.add_field('authorization', signature.headers['authorization'])
+      end
+    end
+
     def create_request(chunk, uri)
       req = case @http_method
             when :post
               Net::HTTP::Post.new(uri.request_uri)
             when :put
               Net::HTTP::Put.new(uri.request_uri)
             end
-      if @auth
-        req.basic_auth(@auth.username, @auth.password)
-      end
-      set_headers(req, chunk)
+      set_headers(req, uri, chunk)
       req.body = @json_array ? "[#{chunk.read.chop}]" : chunk.read
+
+      # At least one authentication method requires the body and other headers, so the order of this call matters
+      set_auth(req, uri)
       req
     end
 
+
     def send_request(uri, req)
       res = if @proxy_uri
               Net::HTTP.start(uri.host, uri.port, @proxy_uri.host, @proxy_uri.port, @proxy_uri.user, @proxy_uri.password, @http_opt) { |http|

test/plugin/test_out_http.rb

@@ -7,6 +7,7 @@
 require 'net/http'
 require 'uri'
 require 'json'
+require 'aws-sdk-core'
 
 # WEBrick's ProcHandler doesn't handle PUT by default
 module WEBrick::HTTPServlet
@@ -390,6 +391,97 @@ def test_basic_auth_with_invalid_auth
     end
   end
 
+
+  sub_test_case 'aws sigv4 auth' do
+    setup do
+      @@fake_aws_credentials = Aws::Credentials.new(
+        'fakeaccess',
+        'fakesecret',
+        'fake session token'
+      )
+    end
+
+    def server_port
+      19883
+    end
+
+    def test_aws_sigv4_sts_role_arn
+      stub(Aws::AssumeRoleCredentials).new do |credentials_provider|
+        stub(credentials_provider).credentials {
+          @@fake_aws_credentials
+        }
+        credentials_provider
+      end
+
+      d = create_driver(config + %[
+          <auth>
+            method aws_sigv4
+            aws_service someservice
+            aws_region my-region-1
+            aws_role_arn arn:aws:iam::123456789012:role/MyRole
+          </auth>
+        ])
+      d.run(default_tag: 'test.http') do
+        test_events.each { |event|
+          d.feed(event)
+        }
+      end
+
+      result = @@result
+      assert_equal 'POST', result.method
+      assert_equal 'application/x-ndjson', result.content_type
+      assert_equal test_events, result.data
+      assert_not_empty result.headers
+      assert_not_nil result.headers['authorization']
+      assert_match /AWS4-HMAC-SHA256 Credential=[a-zA-Z0-9]*\/\d+\/my-region-1\/someservice\/aws4_request/, result.headers['authorization']
+      assert_match /SignedHeaders=content-type;host;x-amz-content-sha256;x-amz-date;x-amz-security-token/, result.headers['authorization']
+      assert_equal @@fake_aws_credentials.session_token, result.headers['x-amz-security-token']
+      assert_not_nil result.headers['x-amz-content-sha256']
+      assert_not_empty result.headers['x-amz-content-sha256']
+      assert_not_nil result.headers['x-amz-security-token']
+      assert_not_empty result.headers['x-amz-security-token']
+      assert_not_nil result.headers['x-amz-date']
+      assert_not_empty result.headers['x-amz-date']
+    end
+
+    def test_aws_sigv4_no_role
+      stub(Aws::CredentialProviderChain).new do |provider_chain|
+        stub(provider_chain).resolve {
+          @@fake_aws_credentials
+        }
+        provider_chain
+      end
+      d = create_driver(config + %[
+          <auth>
+            method aws_sigv4
+            aws_service someservice
+            aws_region my-region-1
+          </auth>
+        ])
+      d.run(default_tag: 'test.http') do
+        test_events.each { |event|
+          d.feed(event)
+        }
+      end
+
+      result = @@result
+      assert_equal 'POST', result.method
+      assert_equal 'application/x-ndjson', result.content_type
+      assert_equal test_events, result.data
+      assert_not_empty result.headers
+      assert_not_nil result.headers['authorization']
+      assert_match /AWS4-HMAC-SHA256 Credential=[a-zA-Z0-9]*\/\d+\/my-region-1\/someservice\/aws4_request/, result.headers['authorization']
+      assert_match /SignedHeaders=content-type;host;x-amz-content-sha256;x-amz-date;x-amz-security-token/, result.headers['authorization']
+      assert_equal @@fake_aws_credentials.session_token, result.headers['x-amz-security-token']
+      assert_not_nil result.headers['x-amz-content-sha256']
+      assert_not_empty result.headers['x-amz-content-sha256']
+      assert_not_nil result.headers['x-amz-security-token']
+      assert_not_empty result.headers['x-amz-security-token']
+      assert_not_nil result.headers['x-amz-date']
+      assert_not_empty result.headers['x-amz-date']
+    end
+  end
+
   sub_test_case 'HTTPS' do
     def server_port
       19882