gitlab-org--gitlab-foss/lib/gitlab/gitaly_client.rb
Sean McGivern b9b0fc8db1 Clean up Gitaly N+1 stack traces
We don't need to know the details of every library involved in these calls; they
will always originate in the GitLab app itself.
2018-07-04 16:11:47 +01:00

466 lines
15 KiB
Ruby

require 'base64'
require 'gitaly'
require 'grpc/health/v1/health_pb'
require 'grpc/health/v1/health_services_pb'
module Gitlab
module GitalyClient
include Gitlab::Metrics::Methods
module MigrationStatus
DISABLED = 1
OPT_IN = 2
OPT_OUT = 3
end
class TooManyInvocationsError < StandardError
attr_reader :call_site, :invocation_count, :max_call_stack
def initialize(call_site, invocation_count, max_call_stack, most_invoked_stack)
@call_site = call_site
@invocation_count = invocation_count
@max_call_stack = max_call_stack
stacks = most_invoked_stack.join('\n') if most_invoked_stack
msg = "GitalyClient##{call_site} called #{invocation_count} times from single request. Potential n+1?"
msg << "\nThe following call site called into Gitaly #{max_call_stack} times:\n#{stacks}\n" if stacks
super(msg)
end
end
SERVER_VERSION_FILE = 'GITALY_SERVER_VERSION'.freeze
MAXIMUM_GITALY_CALLS = 35
CLIENT_NAME = (Sidekiq.server? ? 'gitlab-sidekiq' : 'gitlab-web').freeze
MUTEX = Mutex.new
class << self
attr_accessor :query_time
end
self.query_time = 0
define_histogram :gitaly_migrate_call_duration_seconds do
docstring "Gitaly migration call execution timings"
base_labels gitaly_enabled: nil, feature: nil
end
define_histogram :gitaly_controller_action_duration_seconds do
docstring "Gitaly endpoint histogram by controller and action combination"
base_labels Gitlab::Metrics::Transaction::BASE_LABELS.merge(gitaly_service: nil, rpc: nil)
end
def self.stub(name, storage)
MUTEX.synchronize do
@stubs ||= {}
@stubs[storage] ||= {}
@stubs[storage][name] ||= begin
klass = stub_class(name)
addr = stub_address(storage)
klass.new(addr, :this_channel_is_insecure)
end
end
end
def self.stub_class(name)
if name == :health_check
Grpc::Health::V1::Health::Stub
else
Gitaly.const_get(name.to_s.camelcase.to_sym).const_get(:Stub)
end
end
def self.stub_address(storage)
addr = address(storage)
addr = addr.sub(%r{^tcp://}, '') if URI(addr).scheme == 'tcp'
addr
end
def self.clear_stubs!
MUTEX.synchronize do
@stubs = nil
end
end
def self.random_storage
Gitlab.config.repositories.storages.keys.sample
end
def self.address(storage)
params = Gitlab.config.repositories.storages[storage]
raise "storage not found: #{storage.inspect}" if params.nil?
address = params['gitaly_address']
unless address.present?
raise "storage #{storage.inspect} is missing a gitaly_address"
end
unless URI(address).scheme.in?(%w(tcp unix))
raise "Unsupported Gitaly address: #{address.inspect} does not use URL scheme 'tcp' or 'unix'"
end
address
end
def self.address_metadata(storage)
Base64.strict_encode64(JSON.dump({ storage => { 'address' => address(storage), 'token' => token(storage) } }))
end
# All Gitaly RPC call sites should use GitalyClient.call. This method
# makes sure that per-request authentication headers are set.
#
# This method optionally takes a block which receives the keyword
# arguments hash 'kwargs' that will be passed to gRPC. This allows the
# caller to modify or augment the keyword arguments. The block must
# return a hash.
#
# For example:
#
# GitalyClient.call(storage, service, rpc, request) do |kwargs|
# kwargs.merge(deadline: Time.now + 10)
# end
#
def self.call(storage, service, rpc, request, remote_storage: nil, timeout: nil)
start = Gitlab::Metrics::System.monotonic_time
request_hash = request.is_a?(Google::Protobuf::MessageExts) ? request.to_h : {}
@current_call_id ||= SecureRandom.uuid
enforce_gitaly_request_limits(:call)
kwargs = request_kwargs(storage, timeout, remote_storage: remote_storage)
kwargs = yield(kwargs) if block_given?
stub(service, storage).__send__(rpc, request, kwargs) # rubocop:disable GitlabSecurity/PublicSend
rescue GRPC::Unavailable => ex
handle_grpc_unavailable!(ex)
ensure
duration = Gitlab::Metrics::System.monotonic_time - start
# Keep track, seperately, for the performance bar
self.query_time += duration
gitaly_controller_action_duration_seconds.observe(
current_transaction_labels.merge(gitaly_service: service.to_s, rpc: rpc.to_s),
duration)
add_call_details(id: @current_call_id, feature: service, duration: duration, request: request_hash)
@current_call_id = nil
end
def self.handle_grpc_unavailable!(ex)
status = ex.to_status
raise ex unless status.details == 'Endpoint read failed'
# There is a bug in grpc 1.8.x that causes a client process to get stuck
# always raising '14:Endpoint read failed'. The only thing that we can
# do to recover is to restart the process.
#
# See https://gitlab.com/gitlab-org/gitaly/issues/1029
if Sidekiq.server?
raise Gitlab::SidekiqMiddleware::Shutdown::WantShutdown.new(ex.to_s)
else
# SIGQUIT requests a Unicorn worker to shut down gracefully after the current request.
Process.kill('QUIT', Process.pid)
end
raise ex
end
private_class_method :handle_grpc_unavailable!
def self.current_transaction_labels
Gitlab::Metrics::Transaction.current&.labels || {}
end
private_class_method :current_transaction_labels
def self.request_kwargs(storage, timeout, remote_storage: nil)
encoded_token = Base64.strict_encode64(token(storage).to_s)
metadata = {
'authorization' => "Bearer #{encoded_token}",
'client_name' => CLIENT_NAME
}
feature_stack = Thread.current[:gitaly_feature_stack]
feature = feature_stack && feature_stack[0]
metadata['call_site'] = feature.to_s if feature
metadata['gitaly-servers'] = address_metadata(remote_storage) if remote_storage
metadata.merge!(server_feature_flags)
result = { metadata: metadata }
# nil timeout indicates that we should use the default
timeout = default_timeout if timeout.nil?
return result unless timeout > 0
# Do not use `Time.now` for deadline calculation, since it
# will be affected by Timecop in some tests, but grpc's c-core
# uses system time instead of timecop's time, so tests will fail
# `Time.at(Process.clock_gettime(Process::CLOCK_REALTIME))` will
# circumvent timecop
deadline = Time.at(Process.clock_gettime(Process::CLOCK_REALTIME)) + timeout
result[:deadline] = deadline
result
end
SERVER_FEATURE_FLAGS = %w[gogit_findcommit].freeze
def self.server_feature_flags
SERVER_FEATURE_FLAGS.map do |f|
["gitaly-feature-#{f.tr('_', '-')}", feature_enabled?(f).to_s]
end.to_h
end
def self.token(storage)
params = Gitlab.config.repositories.storages[storage]
raise "storage not found: #{storage.inspect}" if params.nil?
params['gitaly_token'].presence || Gitlab.config.gitaly['token']
end
# Evaluates whether a feature toggle is on or off
def self.feature_enabled?(feature_name, status: MigrationStatus::OPT_IN)
# Disabled features are always off!
return false if status == MigrationStatus::DISABLED
feature = Feature.get("gitaly_#{feature_name}")
# If the feature has been set, always evaluate
if Feature.persisted?(feature)
if feature.percentage_of_time_value > 0
# Probabilistically enable this feature
return Random.rand() * 100 < feature.percentage_of_time_value
end
return feature.enabled?
end
# If the feature has not been set, the default depends
# on it's status
case status
when MigrationStatus::OPT_OUT
true
when MigrationStatus::OPT_IN
opt_into_all_features? && !explicit_opt_in_required.include?(feature_name)
else
false
end
rescue => ex
# During application startup feature lookups in SQL can fail
Rails.logger.warn "exception while checking Gitaly feature status for #{feature_name}: #{ex}"
false
end
# We have a mechanism to let GitLab automatically opt in to all Gitaly
# features. We want to be able to exclude some features from automatic
# opt-in. This function has an override in EE.
def self.explicit_opt_in_required
[]
end
# opt_into_all_features? returns true when the current environment
# is one in which we opt into features automatically
def self.opt_into_all_features?
Rails.env.development? || ENV["GITALY_FEATURE_DEFAULT_ON"] == "1"
end
private_class_method :opt_into_all_features?
def self.migrate(feature, status: MigrationStatus::OPT_IN)
# Enforce limits at both the `migrate` and `call` sites to ensure that
# problems are not hidden by a feature being disabled
enforce_gitaly_request_limits(:migrate)
is_enabled = feature_enabled?(feature, status: status)
metric_name = feature.to_s
metric_name += "_gitaly" if is_enabled
Gitlab::Metrics.measure(metric_name) do
# Some migrate calls wrap other migrate calls
allow_n_plus_1_calls do
feature_stack = Thread.current[:gitaly_feature_stack] ||= []
feature_stack.unshift(feature)
begin
start = Gitlab::Metrics::System.monotonic_time
@current_call_id = SecureRandom.uuid
call_details = { id: @current_call_id }
yield is_enabled
ensure
total_time = Gitlab::Metrics::System.monotonic_time - start
gitaly_migrate_call_duration_seconds.observe({ gitaly_enabled: is_enabled, feature: feature }, total_time)
feature_stack.shift
Thread.current[:gitaly_feature_stack] = nil if feature_stack.empty?
add_call_details(call_details.merge(feature: feature, duration: total_time))
end
end
end
end
# Ensures that Gitaly is not being abuse through n+1 misuse etc
def self.enforce_gitaly_request_limits(call_site)
# Only count limits in request-response environments (not sidekiq for example)
return unless RequestStore.active?
# This is this actual number of times this call was made. Used for information purposes only
actual_call_count = increment_call_count("gitaly_#{call_site}_actual")
# Do no enforce limits in production
return if Rails.env.production? || ENV["GITALY_DISABLE_REQUEST_LIMITS"]
# Check if this call is nested within a allow_n_plus_1_calls
# block and skip check if it is
return if get_call_count(:gitaly_call_count_exception_block_depth) > 0
# This is the count of calls outside of a `allow_n_plus_1_calls` block
# It is used for enforcement but not statistics
permitted_call_count = increment_call_count("gitaly_#{call_site}_permitted")
count_stack
return if permitted_call_count <= MAXIMUM_GITALY_CALLS
raise TooManyInvocationsError.new(call_site, actual_call_count, max_call_count, max_stacks)
end
def self.allow_n_plus_1_calls
return yield unless RequestStore.active?
begin
increment_call_count(:gitaly_call_count_exception_block_depth)
yield
ensure
decrement_call_count(:gitaly_call_count_exception_block_depth)
end
end
def self.get_call_count(key)
RequestStore.store[key] || 0
end
private_class_method :get_call_count
def self.increment_call_count(key)
RequestStore.store[key] ||= 0
RequestStore.store[key] += 1
end
private_class_method :increment_call_count
def self.decrement_call_count(key)
RequestStore.store[key] -= 1
end
private_class_method :decrement_call_count
# Returns an estimate of the number of Gitaly calls made for this
# request
def self.get_request_count
return 0 unless RequestStore.active?
gitaly_migrate_count = get_call_count("gitaly_migrate_actual")
gitaly_call_count = get_call_count("gitaly_call_actual")
# Using the maximum of migrate and call_count will provide an
# indicator of how many Gitaly calls will be made, even
# before a feature is enabled. This provides us with a single
# metric, but not an exact number, but this tradeoff is acceptable
if gitaly_migrate_count > gitaly_call_count
gitaly_migrate_count
else
gitaly_call_count
end
end
def self.reset_counts
return unless RequestStore.active?
%w[migrate call].each do |call_site|
RequestStore.store["gitaly_#{call_site}_actual"] = 0
RequestStore.store["gitaly_#{call_site}_permitted"] = 0
end
end
def self.add_call_details(details)
id = details.delete(:id)
return unless id && RequestStore.active? && RequestStore.store[:peek_enabled]
RequestStore.store['gitaly_call_details'] ||= {}
RequestStore.store['gitaly_call_details'][id] ||= {}
RequestStore.store['gitaly_call_details'][id].merge!(details)
end
def self.list_call_details
return {} unless RequestStore.active? && RequestStore.store[:peek_enabled]
RequestStore.store['gitaly_call_details'] || {}
end
def self.expected_server_version
path = Rails.root.join(SERVER_VERSION_FILE)
path.read.chomp
end
def self.timestamp(t)
Google::Protobuf::Timestamp.new(seconds: t.to_i)
end
# The default timeout on all Gitaly calls
def self.default_timeout
return 0 if Sidekiq.server?
timeout(:gitaly_timeout_default)
end
def self.fast_timeout
timeout(:gitaly_timeout_fast)
end
def self.medium_timeout
timeout(:gitaly_timeout_medium)
end
def self.timeout(timeout_name)
Gitlab::CurrentSettings.current_application_settings[timeout_name]
end
private_class_method :timeout
# Count a stack. Used for n+1 detection
def self.count_stack
return unless RequestStore.active?
stack_string = Gitlab::Profiler.clean_backtrace(caller).drop(1).join("\n")
RequestStore.store[:stack_counter] ||= Hash.new
count = RequestStore.store[:stack_counter][stack_string] || 0
RequestStore.store[:stack_counter][stack_string] = count + 1
end
private_class_method :count_stack
# Returns a count for the stack which called Gitaly the most times. Used for n+1 detection
def self.max_call_count
return 0 unless RequestStore.active?
stack_counter = RequestStore.store[:stack_counter]
return 0 unless stack_counter
stack_counter.values.max
end
private_class_method :max_call_count
# Returns the stacks that calls Gitaly the most times. Used for n+1 detection
def self.max_stacks
return nil unless RequestStore.active?
stack_counter = RequestStore.store[:stack_counter]
return nil unless stack_counter
max = max_call_count
return nil if max.zero?
stack_counter.select { |_, v| v == max }.keys
end
private_class_method :max_stacks
end
end