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authorYorick Peterse <yorickpeterse@gmail.com>2015-12-09 16:45:51 +0100
committerYorick Peterse <yorickpeterse@gmail.com>2015-12-17 17:25:48 +0100
commit141e946c3da97c7af02aaca5324c6e4ce7362a04 (patch)
tree15fc780a8d99785f5ae3b069fa49c38d83e02002 /lib
parentb2c593dac513c0e12153e0aa786759c4ebc996bc (diff)
downloadgitlab-ce-141e946c3da97c7af02aaca5324c6e4ce7362a04.tar.gz
Storing of application metrics in InfluxDB
This adds the ability to write application metrics (e.g. SQL timings) to InfluxDB. These metrics can in turn be visualized using Grafana, or really anything else that can read from InfluxDB. These metrics can be used to track application performance over time, between different Ruby versions, different GitLab versions, etc. == Transaction Metrics Currently the following is tracked on a per transaction basis (a transaction is a Rails request or a single Sidekiq job): * Timings per query along with the raw (obfuscated) SQL and information about what file the query originated from. * Timings per view along with the path of the view and information about what file triggered the rendering process. * The duration of a request itself along with the controller/worker class and method name. * The duration of any instrumented method calls (more below). == Sampled Metrics Certain metrics can't be directly associated with a transaction. For example, a process' total memory usage is unrelated to any running transactions. While a transaction can result in the memory usage going up there's no accurate way to determine what transaction is to blame, this becomes especially problematic in multi-threaded environments. To solve this problem there's a separate thread that takes samples at a fixed interval. This thread (using the class Gitlab::Metrics::Sampler) currently tracks the following: * The process' total memory usage. * The number of file descriptors opened by the process. * The amount of Ruby objects (using ObjectSpace.count_objects). * GC statistics such as timings, heap slots, etc. The default/current interval is 15 seconds, any smaller interval might put too much pressure on InfluxDB (especially when running dozens of processes). == Method Instrumentation While currently not yet used methods can be instrumented to track how long they take to run. Unlike the likes of New Relic this doesn't require modifying the source code (e.g. including modules), it all happens from the outside. For example, to track `User.by_login` we'd add the following code somewhere in an initializer: Gitlab::Metrics::Instrumentation. instrument_method(User, :by_login) to instead instrument an instance method: Gitlab::Metrics::Instrumentation. instrument_instance_method(User, :save) Instrumentation for either all public model methods or a few crucial ones will be added in the near future, I simply haven't gotten to doing so just yet. == Configuration By default metrics are disabled. This means users don't have to bother setting anything up if they don't want to. Metrics can be enabled by editing one's gitlab.yml configuration file (see config/gitlab.yml.example for example settings). == Writing Data To InfluxDB Because InfluxDB is still a fairly young product I expect the worse. Data loss, unexpected reboots, the database not responding, you name it. Because of this data is _not_ written to InfluxDB directly, instead it's queued and processed by Sidekiq. This ensures that users won't notice anything when InfluxDB is giving trouble. The metrics worker can be started in a standalone manner as following: bundle exec sidekiq -q metrics The corresponding class is called MetricsWorker.
Diffstat (limited to 'lib')
-rw-r--r--lib/gitlab/metrics.rb52
-rw-r--r--lib/gitlab/metrics/delta.rb32
-rw-r--r--lib/gitlab/metrics/instrumentation.rb47
-rw-r--r--lib/gitlab/metrics/metric.rb34
-rw-r--r--lib/gitlab/metrics/obfuscated_sql.rb39
-rw-r--r--lib/gitlab/metrics/rack_middleware.rb49
-rw-r--r--lib/gitlab/metrics/sampler.rb77
-rw-r--r--lib/gitlab/metrics/sidekiq_middleware.rb30
-rw-r--r--lib/gitlab/metrics/subscribers/action_view.rb48
-rw-r--r--lib/gitlab/metrics/subscribers/active_record.rb43
-rw-r--r--lib/gitlab/metrics/subscribers/method_call.rb42
-rw-r--r--lib/gitlab/metrics/system.rb35
-rw-r--r--lib/gitlab/metrics/transaction.rb66
13 files changed, 594 insertions, 0 deletions
diff --git a/lib/gitlab/metrics.rb b/lib/gitlab/metrics.rb
new file mode 100644
index 00000000000..08393995165
--- /dev/null
+++ b/lib/gitlab/metrics.rb
@@ -0,0 +1,52 @@
+module Gitlab
+ module Metrics
+ def self.pool_size
+ Settings.metrics['pool_size'] || 16
+ end
+
+ def self.timeout
+ Settings.metrics['timeout'] || 10
+ end
+
+ def self.enabled?
+ !!Settings.metrics['enabled']
+ end
+
+ def self.pool
+ @pool
+ end
+
+ def self.hostname
+ @hostname
+ end
+
+ def self.last_relative_application_frame
+ root = Rails.root.to_s
+ metrics = Rails.root.join('lib', 'gitlab', 'metrics').to_s
+
+ frame = caller_locations.find do |l|
+ l.path.start_with?(root) && !l.path.start_with?(metrics)
+ end
+
+ if frame
+ return frame.path.gsub(/^#{Rails.root.to_s}\/?/, ''), frame.lineno
+ else
+ return nil, nil
+ end
+ end
+
+ @hostname = Socket.gethostname
+
+ # When enabled this should be set before being used as the usual pattern
+ # "@foo ||= bar" is _not_ thread-safe.
+ if enabled?
+ @pool = ConnectionPool.new(size: pool_size, timeout: timeout) do
+ db = Settings.metrics['database']
+ user = Settings.metrics['username']
+ pw = Settings.metrics['password']
+
+ InfluxDB::Client.new(db, username: user, password: pw)
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/delta.rb b/lib/gitlab/metrics/delta.rb
new file mode 100644
index 00000000000..bcf28eed84d
--- /dev/null
+++ b/lib/gitlab/metrics/delta.rb
@@ -0,0 +1,32 @@
+module Gitlab
+ module Metrics
+ # Class for calculating the difference between two numeric values.
+ #
+ # Every call to `compared_with` updates the internal value. This makes it
+ # possible to use a single Delta instance to calculate the delta over time
+ # of an ever increasing number.
+ #
+ # Example usage:
+ #
+ # delta = Delta.new(0)
+ #
+ # delta.compared_with(10) # => 10
+ # delta.compared_with(15) # => 5
+ # delta.compared_with(20) # => 5
+ class Delta
+ def initialize(value = 0)
+ @value = value
+ end
+
+ # new_value - The value to compare with as a Numeric.
+ #
+ # Returns a new Numeric (depending on the type of `new_value`).
+ def compared_with(new_value)
+ delta = new_value - @value
+ @value = new_value
+
+ delta
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/instrumentation.rb b/lib/gitlab/metrics/instrumentation.rb
new file mode 100644
index 00000000000..1c2f84fb09a
--- /dev/null
+++ b/lib/gitlab/metrics/instrumentation.rb
@@ -0,0 +1,47 @@
+module Gitlab
+ module Metrics
+ # Module for instrumenting methods.
+ #
+ # This module allows instrumenting of methods without having to actually
+ # alter the target code (e.g. by including modules).
+ #
+ # Example usage:
+ #
+ # Gitlab::Metrics::Instrumentation.instrument_method(User, :by_login)
+ module Instrumentation
+ # Instruments a class method.
+ #
+ # mod - The module to instrument as a Module/Class.
+ # name - The name of the method to instrument.
+ def self.instrument_method(mod, name)
+ instrument(:class, mod, name)
+ end
+
+ # Instruments an instance method.
+ #
+ # mod - The module to instrument as a Module/Class.
+ # name - The name of the method to instrument.
+ def self.instrument_instance_method(mod, name)
+ instrument(:instance, mod, name)
+ end
+
+ def self.instrument(type, mod, name)
+ return unless Metrics.enabled?
+
+ alias_name = "_original_#{name}"
+ target = type == :instance ? mod : mod.singleton_class
+
+ target.class_eval do
+ alias_method(alias_name, name)
+
+ define_method(name) do |*args, &block|
+ ActiveSupport::Notifications.
+ instrument("#{type}_method.method_call", module: mod, name: name) do
+ __send__(alias_name, *args, &block)
+ end
+ end
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/metric.rb b/lib/gitlab/metrics/metric.rb
new file mode 100644
index 00000000000..f592f4e571f
--- /dev/null
+++ b/lib/gitlab/metrics/metric.rb
@@ -0,0 +1,34 @@
+module Gitlab
+ module Metrics
+ # Class for storing details of a single metric (label, value, etc).
+ class Metric
+ attr_reader :series, :values, :tags, :created_at
+
+ # series - The name of the series (as a String) to store the metric in.
+ # values - A Hash containing the values to store.
+ # tags - A Hash containing extra tags to add to the metrics.
+ def initialize(series, values, tags = {})
+ @values = values
+ @series = series
+ @tags = tags
+ @created_at = Time.now.utc
+ end
+
+ # Returns a Hash in a format that can be directly written to InfluxDB.
+ def to_hash
+ {
+ series: @series,
+ tags: @tags.merge(
+ hostname: Metrics.hostname,
+ ruby_engine: RUBY_ENGINE,
+ ruby_version: RUBY_VERSION,
+ gitlab_version: Gitlab::VERSION,
+ process_type: Sidekiq.server? ? 'sidekiq' : 'rails'
+ ),
+ values: @values,
+ timestamp: @created_at.to_i
+ }
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/obfuscated_sql.rb b/lib/gitlab/metrics/obfuscated_sql.rb
new file mode 100644
index 00000000000..45f2e2bc62a
--- /dev/null
+++ b/lib/gitlab/metrics/obfuscated_sql.rb
@@ -0,0 +1,39 @@
+module Gitlab
+ module Metrics
+ # Class for producing SQL queries with sensitive data stripped out.
+ class ObfuscatedSQL
+ REPLACEMENT = /
+ \d+(\.\d+)? # integers, floats
+ | '.+?' # single quoted strings
+ | \/.+?(?<!\\)\/ # regexps (including escaped slashes)
+ /x
+
+ MYSQL_REPLACEMENTS = /
+ ".+?" # double quoted strings
+ /x
+
+ # Regex to replace consecutive placeholders with a single one indicating
+ # the length. This can be useful when a "IN" statement uses thousands of
+ # IDs (storing this would just be a waste of space).
+ CONSECUTIVE = /(\?(\s*,\s*)?){2,}/
+
+ # sql - The raw SQL query as a String.
+ def initialize(sql)
+ @sql = sql
+ end
+
+ # Returns a new, obfuscated SQL query.
+ def to_s
+ regex = REPLACEMENT
+
+ if Gitlab::Database.mysql?
+ regex = Regexp.union(regex, MYSQL_REPLACEMENTS)
+ end
+
+ @sql.gsub(regex, '?').gsub(CONSECUTIVE) do |match|
+ "#{match.count(',') + 1} values"
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/rack_middleware.rb b/lib/gitlab/metrics/rack_middleware.rb
new file mode 100644
index 00000000000..5c0587c4c51
--- /dev/null
+++ b/lib/gitlab/metrics/rack_middleware.rb
@@ -0,0 +1,49 @@
+module Gitlab
+ module Metrics
+ # Rack middleware for tracking Rails requests.
+ class RackMiddleware
+ CONTROLLER_KEY = 'action_controller.instance'
+
+ def initialize(app)
+ @app = app
+ end
+
+ # env - A Hash containing Rack environment details.
+ def call(env)
+ trans = transaction_from_env(env)
+ retval = nil
+
+ begin
+ retval = trans.run { @app.call(env) }
+
+ # Even in the event of an error we want to submit any metrics we
+ # might've gathered up to this point.
+ ensure
+ if env[CONTROLLER_KEY]
+ tag_controller(trans, env)
+ end
+
+ trans.finish
+ end
+
+ retval
+ end
+
+ def transaction_from_env(env)
+ trans = Transaction.new
+
+ trans.add_tag(:request_method, env['REQUEST_METHOD'])
+ trans.add_tag(:request_uri, env['REQUEST_URI'])
+
+ trans
+ end
+
+ def tag_controller(trans, env)
+ controller = env[CONTROLLER_KEY]
+ label = "#{controller.class.name}##{controller.action_name}"
+
+ trans.add_tag(:action, label)
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/sampler.rb b/lib/gitlab/metrics/sampler.rb
new file mode 100644
index 00000000000..141953dc985
--- /dev/null
+++ b/lib/gitlab/metrics/sampler.rb
@@ -0,0 +1,77 @@
+module Gitlab
+ module Metrics
+ # Class that sends certain metrics to InfluxDB at a specific interval.
+ #
+ # This class is used to gather statistics that can't be directly associated
+ # with a transaction such as system memory usage, garbage collection
+ # statistics, etc.
+ class Sampler
+ # interval - The sampling interval in seconds.
+ def initialize(interval = 15)
+ @interval = interval
+ @metrics = []
+
+ @last_minor_gc = Delta.new(GC.stat[:minor_gc_count])
+ @last_major_gc = Delta.new(GC.stat[:major_gc_count])
+ end
+
+ def start
+ Thread.new do
+ Thread.current.abort_on_exception = true
+
+ loop do
+ sleep(@interval)
+
+ sample
+ end
+ end
+ end
+
+ def sample
+ sample_memory_usage
+ sample_file_descriptors
+ sample_objects
+ sample_gc
+
+ flush
+ ensure
+ GC::Profiler.clear
+ @metrics.clear
+ end
+
+ def flush
+ MetricsWorker.perform_async(@metrics.map(&:to_hash))
+ end
+
+ def sample_memory_usage
+ @metrics << Metric.new('memory_usage', value: System.memory_usage)
+ end
+
+ def sample_file_descriptors
+ @metrics << Metric.
+ new('file_descriptors', value: System.file_descriptor_count)
+ end
+
+ def sample_objects
+ @metrics << Metric.new('object_counts', ObjectSpace.count_objects)
+ end
+
+ def sample_gc
+ time = GC::Profiler.total_time * 1000.0
+ stats = GC.stat.merge(total_time: time)
+
+ # We want the difference of GC runs compared to the last sample, not the
+ # total amount since the process started.
+ stats[:minor_gc_count] =
+ @last_minor_gc.compared_with(stats[:minor_gc_count])
+
+ stats[:major_gc_count] =
+ @last_major_gc.compared_with(stats[:major_gc_count])
+
+ stats[:count] = stats[:minor_gc_count] + stats[:major_gc_count]
+
+ @metrics << Metric.new('gc_statistics', stats)
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/sidekiq_middleware.rb b/lib/gitlab/metrics/sidekiq_middleware.rb
new file mode 100644
index 00000000000..ec10707d1fb
--- /dev/null
+++ b/lib/gitlab/metrics/sidekiq_middleware.rb
@@ -0,0 +1,30 @@
+module Gitlab
+ module Metrics
+ # Sidekiq middleware for tracking jobs.
+ #
+ # This middleware is intended to be used as a server-side middleware.
+ class SidekiqMiddleware
+ def call(worker, message, queue)
+ # We don't want to track the MetricsWorker itself as otherwise we'll end
+ # up in an infinite loop.
+ if worker.class == MetricsWorker
+ yield
+ return
+ end
+
+ trans = Transaction.new
+
+ begin
+ trans.run { yield }
+ ensure
+ tag_worker(trans, worker)
+ trans.finish
+ end
+ end
+
+ def tag_worker(trans, worker)
+ trans.add_tag(:action, "#{worker.class.name}#perform")
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/subscribers/action_view.rb b/lib/gitlab/metrics/subscribers/action_view.rb
new file mode 100644
index 00000000000..2e88e4bea6a
--- /dev/null
+++ b/lib/gitlab/metrics/subscribers/action_view.rb
@@ -0,0 +1,48 @@
+module Gitlab
+ module Metrics
+ module Subscribers
+ # Class for tracking the rendering timings of views.
+ class ActionView < ActiveSupport::Subscriber
+ attach_to :action_view
+
+ SERIES = 'views'
+
+ def render_template(event)
+ track(event) if current_transaction
+ end
+
+ alias_method :render_view, :render_template
+
+ private
+
+ def track(event)
+ path = relative_path(event.payload[:identifier])
+ values = values_for(event)
+
+ current_transaction.add_metric(SERIES, values, path: path)
+ end
+
+ def relative_path(path)
+ path.gsub(/^#{Rails.root.to_s}\/?/, '')
+ end
+
+ def values_for(event)
+ values = { duration: event.duration }
+
+ file, line = Metrics.last_relative_application_frame
+
+ if file and line
+ values[:file] = file
+ values[:line] = line
+ end
+
+ values
+ end
+
+ def current_transaction
+ Transaction.current
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/subscribers/active_record.rb b/lib/gitlab/metrics/subscribers/active_record.rb
new file mode 100644
index 00000000000..3cc9b1addf6
--- /dev/null
+++ b/lib/gitlab/metrics/subscribers/active_record.rb
@@ -0,0 +1,43 @@
+module Gitlab
+ module Metrics
+ module Subscribers
+ # Class for tracking raw SQL queries.
+ #
+ # Queries are obfuscated before being logged to ensure no private data is
+ # exposed via InfluxDB/Grafana.
+ class ActiveRecord < ActiveSupport::Subscriber
+ attach_to :active_record
+
+ SERIES = 'sql_queries'
+
+ def sql(event)
+ return unless current_transaction
+
+ sql = ObfuscatedSQL.new(event.payload[:sql]).to_s
+ values = values_for(event)
+
+ current_transaction.add_metric(SERIES, values, sql: sql)
+ end
+
+ private
+
+ def values_for(event)
+ values = { duration: event.duration }
+
+ file, line = Metrics.last_relative_application_frame
+
+ if file and line
+ values[:file] = file
+ values[:line] = line
+ end
+
+ values
+ end
+
+ def current_transaction
+ Transaction.current
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/subscribers/method_call.rb b/lib/gitlab/metrics/subscribers/method_call.rb
new file mode 100644
index 00000000000..1606134b7e5
--- /dev/null
+++ b/lib/gitlab/metrics/subscribers/method_call.rb
@@ -0,0 +1,42 @@
+module Gitlab
+ module Metrics
+ module Subscribers
+ # Class for tracking method call timings.
+ class MethodCall < ActiveSupport::Subscriber
+ attach_to :method_call
+
+ SERIES = 'method_calls'
+
+ def instance_method(event)
+ return unless current_transaction
+
+ label = "#{event.payload[:module].name}##{event.payload[:name]}"
+
+ add_metric(label, event.duration)
+ end
+
+ def class_method(event)
+ return unless current_transaction
+
+ label = "#{event.payload[:module].name}.#{event.payload[:name]}"
+
+ add_metric(label, event.duration)
+ end
+
+ private
+
+ def add_metric(label, duration)
+ file, line = Metrics.last_relative_application_frame
+
+ values = { duration: duration, file: file, line: line }
+
+ current_transaction.add_metric(SERIES, values, method: label)
+ end
+
+ def current_transaction
+ Transaction.current
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/system.rb b/lib/gitlab/metrics/system.rb
new file mode 100644
index 00000000000..83371265278
--- /dev/null
+++ b/lib/gitlab/metrics/system.rb
@@ -0,0 +1,35 @@
+module Gitlab
+ module Metrics
+ # Module for gathering system/process statistics such as the memory usage.
+ #
+ # This module relies on the /proc filesystem being available. If /proc is
+ # not available the methods of this module will be stubbed.
+ module System
+ if File.exist?('/proc')
+ # Returns the current process' memory usage in bytes.
+ def self.memory_usage
+ mem = 0
+ match = File.read('/proc/self/status').match(/VmRSS:\s+(\d+)/)
+
+ if match and match[1]
+ mem = match[1].to_f * 1024
+ end
+
+ mem
+ end
+
+ def self.file_descriptor_count
+ Dir.glob('/proc/self/fd/*').length
+ end
+ else
+ def self.memory_usage
+ 0.0
+ end
+
+ def self.file_descriptor_count
+ 0
+ end
+ end
+ end
+ end
+end
diff --git a/lib/gitlab/metrics/transaction.rb b/lib/gitlab/metrics/transaction.rb
new file mode 100644
index 00000000000..568f9d6ae0c
--- /dev/null
+++ b/lib/gitlab/metrics/transaction.rb
@@ -0,0 +1,66 @@
+module Gitlab
+ module Metrics
+ # Class for storing metrics information of a single transaction.
+ class Transaction
+ THREAD_KEY = :_gitlab_metrics_transaction
+
+ SERIES = 'transactions'
+
+ attr_reader :uuid, :tags
+
+ def self.current
+ Thread.current[THREAD_KEY]
+ end
+
+ # name - The name of this transaction as a String.
+ def initialize
+ @metrics = []
+ @uuid = SecureRandom.uuid
+
+ @started_at = nil
+ @finished_at = nil
+
+ @tags = {}
+ end
+
+ def duration
+ @finished_at ? (@finished_at - @started_at) * 1000.0 : 0.0
+ end
+
+ def run
+ Thread.current[THREAD_KEY] = self
+
+ @started_at = Time.now
+
+ yield
+ ensure
+ @finished_at = Time.now
+
+ Thread.current[THREAD_KEY] = nil
+ end
+
+ def add_metric(series, values, tags = {})
+ tags = tags.merge(transaction_id: @uuid)
+
+ @metrics << Metric.new(series, values, tags)
+ end
+
+ def add_tag(key, value)
+ @tags[key] = value
+ end
+
+ def finish
+ track_self
+ submit
+ end
+
+ def track_self
+ add_metric(SERIES, { duration: duration }, @tags)
+ end
+
+ def submit
+ MetricsWorker.perform_async(@metrics.map(&:to_hash))
+ end
+ end
+ end
+end