Redis disable spans

lib/instana/span_filtering/configuration.rb

@@ -83,16 +83,24 @@ def check_discovery
       def process_discovery_config(discovery)
         # Check if tracing configuration exists in the discovery response
         tracing_config = discovery['tracing']
-        return unless tracing_config && tracing_config['filter']
+        return unless tracing_config
 
-        filter_config = tracing_config['filter']
-        @deactivated = filter_config['deactivate'] == true
+        # Process filter configuration
+        if tracing_config['filter']
+          filter_config = tracing_config['filter']
+          @deactivated = filter_config['deactivate'] == true
 
-        # Process include rules
-        process_rules(filter_config['include'], true) if filter_config['include']
+          # Process include rules
+          process_rules(filter_config['include'], true) if filter_config['include']
+
+          # Process exclude rules
+          process_rules(filter_config['exclude'], false) if filter_config['exclude']
+        end
 
-        # Process exclude rules
-        process_rules(filter_config['exclude'], false) if filter_config['exclude']
+        # Process disable configuration
+        if tracing_config['disable']
+          process_disable_config(tracing_config['disable'])
+        end
 
         # Return true to indicate successful processing
         true
@@ -117,16 +125,24 @@ def load_from_yaml
           # Support both "tracing" and "com.instana.tracing" as top-level keys
           tracing_config = yaml_content['tracing'] || yaml_content['com.instana.tracing']
           ::Instana.logger.warn(TRACING_CONFIG_WARNING) if yaml_content.key?('com.instana.tracing')
-          return unless tracing_config && tracing_config['filter']
+          return unless tracing_config
 
-          filter_config = tracing_config['filter']
-          @deactivated = filter_config['deactivate'] == true
+          # Process filter configuration
+          if tracing_config['filter']
+            filter_config = tracing_config['filter']
+            @deactivated = filter_config['deactivate'] == true
 
-          # Process include rules
-          process_rules(filter_config['include'], true) if filter_config['include']
+            # Process include rules
+            process_rules(filter_config['include'], true) if filter_config['include']
 
-          # Process exclude rules
-          process_rules(filter_config['exclude'], false) if filter_config['exclude']
+            # Process exclude rules
+            process_rules(filter_config['exclude'], false) if filter_config['exclude']
+          end
+
+          # Process disable configuration
+          if tracing_config['disable']
+            process_disable_config(tracing_config['disable'])
+          end
         rescue => e
           Instana.logger.warn("Failed to load span filtering configuration from YAML: #{e.message}")
         end
@@ -149,6 +165,10 @@ def load_from_env_vars
             process_env_suppression(parts[3..].join('_'), value)
           end
         end
+
+        return unless !ENV["INSTANA_TRACING_DISABLE"].nil? && !%w[True true 1].include?(ENV["INSTANA_TRACING_DISABLE"])
+
+        process_disable_config(ENV["INSTANA_TRACING_DISABLE"].split(','))
       end
 
       # Process rules from YAML configuration
@@ -205,6 +225,38 @@ def process_env_suppression(policy_name, value)
         suppression = %w[1 true True].include?(value)
         @exclude_rules[rule_index].suppression = suppression
       end
+
+      # Process disable configuration from YAML or agent discovery
+      # @param disable_config [Array] The disable configuration array
+      def process_disable_config(disable_config)
+        return unless disable_config.is_a?(Array)
+
+        disable_config.each do |item|
+          if item.is_a?(Hash)
+            item.each do |key, value|
+              if value == true
+                update_instana_config_for_disabled_technology(key)
+              end
+            end
+          elsif item.is_a?(String)
+            update_instana_config_for_disabled_technology(item)
+          end
+        end
+      end
+
+      # Update Instana::Config for a disabled technology
+      # @param technology [String] The technology to disable
+      def update_instana_config_for_disabled_technology(technology)
+        tech_sym = technology.to_sym
+
+        case tech_sym
+        when :redis
+          ::Instana.config[:redis][:enabled] = false
+        when :databases
+          # If databases category is disabled, also disable redis
+          ::Instana.config[:redis][:enabled] = false
+        end
+      end
     end
   end
 end

test/instrumentation/redis_disable_test.rb

@@ -0,0 +1,155 @@
+# (c) Copyright IBM Corp. 2025
+
+require 'test_helper'
+
+class RedisDisableTest < Minitest::Test
+  def setup
+    @redis_url = if ENV.key?('REDIS_URL')
+                   ENV['REDIS_URL']
+                 else
+                   "redis://localhost:6379"
+                 end
+    @redis_client = Redis.new(url: @redis_url)
+
+    # Reset span filtering configuration before each test
+    ::Instana::SpanFiltering.reset
+    ::Instana::SpanFiltering.initialize
+
+    # Reset Redis configuration
+    ::Instana.config[:redis] = { :enabled => true }
+
+    clear_all!
+  end
+
+  def teardown
+    # Reset span filtering configuration after each test
+    ::Instana::SpanFiltering.reset
+    ::Instana::SpanFiltering.initialize
+
+    # Reset Redis configuration
+    ::Instana.config[:redis] = { :enabled => true }
+  end
+
+  def test_redis_disabled_by_configuration
+    # Set Redis to be disabled via configuration
+    ::Instana.config[:redis][:enabled] = false
+
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that only the parent span is reported (Redis span is disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 1, spans.length
+    assert_equal :sdk, spans[0][:n]
+  end
+
+  def test_redis_disabled_via_databases_category
+    # Create a mock configuration that disables the databases category
+    config = ::Instana::SpanFiltering::Configuration.new
+
+    # Simulate disabling databases category
+    config.send(:update_instana_config_for_disabled_technology, 'databases')
+
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that only the parent span is reported (Redis span is disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 1, spans.length
+    assert_equal :sdk, spans[0][:n]
+  end
+
+  def test_redis_disabled_via_yaml_config
+    # Create a test YAML configuration file
+    yaml_content = <<~YAML
+      tracing:
+        disable:
+          - redis
+    YAML
+
+    File.write('test_redis_config.yaml', yaml_content)
+    ENV['INSTANA_CONFIG_PATH'] = 'test_redis_config.yaml'
+
+    # Create a new configuration that should load from our YAML file
+    ::Instana::SpanFiltering::Configuration.new
+
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that only the parent span is reported (Redis span is disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 1, spans.length
+    assert_equal :sdk, spans[0][:n]
+  ensure
+    # Remove test config file
+    File.unlink('test_redis_config.yaml') if File.exist?('test_redis_config.yaml')
+    ENV.delete('INSTANA_CONFIG_PATH')
+  end
+
+  def test_redis_disabled_via_env_var
+    # Set environment variable to disable Redis
+    ENV['INSTANA_TRACING_DISABLE'] = 'redis'
+
+    # Create a new configuration that should load from our environment variable
+    ::Instana::SpanFiltering::Configuration.new
+
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that only the parent span is reported (Redis span is disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 1, spans.length
+    assert_equal :sdk, spans[0][:n]
+  ensure
+    ENV.delete('INSTANA_TRACING_DISABLE')
+  end
+
+  def test_redis_disabled_via_databases_env_var
+    # Set environment variable to disable databases category
+    ENV['INSTANA_TRACING_DISABLE'] = 'databases'
+
+    # Create a new configuration that should load from our environment variable
+    ::Instana::SpanFiltering::Configuration.new
+
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that only the parent span is reported (Redis span is disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 1, spans.length
+    assert_equal :sdk, spans[0][:n]
+  ensure
+    ENV.delete('INSTANA_TRACING_DISABLE')
+  end
+
+  def test_redis_not_disabled_by_default
+    # Execute Redis operation
+    Instana.tracer.in_span(:redis_test) do
+      @redis_client.set('hello', 'world')
+    end
+
+    # Verify that both spans are reported (Redis span is not disabled)
+    spans = ::Instana.processor.queued_spans
+    assert_equal 2, spans.length
+    first_span, second_span = spans.to_a.reverse
+    assert_equal :sdk, first_span[:n]
+    assert_equal :redis, second_span[:n]
+  end
+
+  private
+
+  def clear_all!
+    ::Instana.processor.clear!
+    ::Instana.tracer.clear!
+  end
+end

test/instrumentation/redis_test.rb

@@ -5,6 +5,7 @@
 
 class RedisTest < Minitest::Test
   def setup
+    ::Instana.config[:redis] = { :enabled => true }
     if ENV.key?('REDIS_URL')
       @redis_url = ENV['REDIS_URL']
     else