Add a Redis interceptor to trace all Redis calls (54ae95c1) · Commits · GitLab.org / ruby / gems / labkit-ruby

gitlab-labkit.gemspec

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		@@ -24,6 +24,7 @@ Gem::Specification.new do \|spec\|
		spec.add_runtime_dependency "grpc", "~> 1.19" # Be sure to update the "grpc-tools" dev_depenency too
		spec.add_runtime_dependency "jaeger-client", "~> 0.10"
		spec.add_runtime_dependency "opentracing", "~> 0.4"
		spec.add_runtime_dependency "redis", "~> 3.2"

		# Please maintain alphabetical order for dev dependencies
		spec.add_development_dependency "grpc-tools", "~> 1.19"

lib/labkit/tracing.rb

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		@@ -11,6 +11,7 @@ module Labkit
		autoload :JaegerFactory, "labkit/tracing/jaeger_factory"
		autoload :RackMiddleware, "labkit/tracing/rack_middleware"
		autoload :Rails, "labkit/tracing/rails"
		autoload :Redis, "labkit/tracing/redis"
		autoload :Sidekiq, "labkit/tracing/sidekiq"
		autoload :TracingUtils, "labkit/tracing/tracing_utils"

lib/labkit/tracing/redis.rb

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		# frozen_string_literal: true

		require "redis"

		module Labkit
		module Tracing
		# The Redis interceptor will intercept all calls to Redis and instrument them for distributed tracing
		module Redis
		autoload :RedisInterceptor, "labkit/tracing/redis/redis_interceptor"
		autoload :RedisInterceptorHelper, "labkit/tracing/redis/redis_interceptor_helper"

		def self.instrument
		::Redis::Client.prepend RedisInterceptor
		end
		end
		end
		end

lib/labkit/tracing/redis/redis_interceptor.rb

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		# frozen_string_literal: true

		require "redis"

		module Labkit
		module Tracing
		module Redis
		# RedisInterceptor is an interceptor for Redis to add distributed tracing.
		# It should be installed using the `Labkit::Tracing.instrument` method
		module RedisInterceptor
		def call(command)
		RedisInterceptorHelper.call_with_tracing(command, self) do
		# Note: when used without any arguments super uses the arguments given to the subclass method.
		super
		end
		end

		def call_pipeline(pipeline)
		RedisInterceptorHelper.call_pipeline_with_tracing(pipeline, self) do
		# Note: when used without any arguments super uses the arguments given to the subclass method.
		super
		end
		end
		end
		end
		end
		end

lib/labkit/tracing/redis/redis_interceptor_helper.rb

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		# frozen_string_literal: true

		require "redis"

		module Labkit
		module Tracing
		module Redis
		# RedisInterceptorHelper is a helper for the RedisInterceptor. This is not a public API
		class RedisInterceptorHelper
		# For optimization, compile this once
		MASK_REDIS_RE = /^([\w-]+(?:\W+[\w-]+(?:\W+[\w-]+)?)?)(.?)/.freeze

		def self.call_with_tracing(command, client)
		Labkit::Tracing::TracingUtils.with_tracing(operation_name: "redis.call", tags: tags_from_command(command, client)) do \|_span\|
		yield
		end
		end

		def self.call_pipeline_with_tracing(pipeline, client)
		Labkit::Tracing::TracingUtils.with_tracing(operation_name: "redis.call_pipeline", tags: tags_from_pipeline(pipeline, client)) do \|_span\|
		yield
		end
		end

		def self.common_tags_for_client(client)
		{
		"component" => "redis",
		"span.kind" => "client",
		"redis.scheme" => client.scheme,
		"redis.host" => client.host,
		"redis.port" => client.port,
		"redis.path" => client.path,
		}
		end

		def self.tags_from_command(command, client)
		tags = common_tags_for_client(client)

		tags["redis.command"] = command_serialized(command)

		tags
		end

		def self.command_serialized(command)
		command_name, *arguments = command

		info = [command_name]
		info << sanitize_argument_for_command(command_name, arguments.first) unless arguments.empty?

		# Additional arguments? Only include the number
		info << "...#{arguments.size - 1} more value(s)" if arguments.size > 1

		info.join(" ")
		end

		def self.tags_from_pipeline(pipeline, client)
		tags = common_tags_for_client(client)

		commands = pipeline.commands

		# Limit to the first 5 commands
		commands.first(5).each_with_index do \|command, index\|
		tags["redis.command.#{index}"] = command_serialized(command)
		end
		tags["redis.pipeline.commands.length"] = commands.length

		tags
		end

		# get_first_argument_for_command returns a masked value representing the first argument
		# from a redis command, taking care of certain sensitive commands
		def self.sanitize_argument_for_command(command_name, first_argument)
		return "*****" if command_is_sensitive(command_name)

		return "nil" if first_argument.nil?
		return first if first_argument.is_a?(Numeric)
		return "*****" unless first_argument.is_a?(String)

		mask_redis_arg(first_argument)
		end

		def self.command_is_sensitive(command_name)
		return true if command_name == :auth \|\| "auth".casecmp(command_name).zero?
		return true if command_name == :eval \|\| "eval".casecmp(command_name).zero?

		false
		end

		def self.mask_redis_arg(argument)
		return "" if argument.empty?

		matches = argument.match(MASK_REDIS_RE)
		matches[2].empty? ? matches[0] : matches[0] + "*****"
		end
		private_class_method :mask_redis_arg
		end
		end
		end
		end