Class: ActiveSupport::LogSubscriber
- Inherits:
-
Subscriber
- Object
- Subscriber
- ActiveSupport::LogSubscriber
- Defined in:
- lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb,
lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber/test_helper.rb
Overview
ActiveSupport::LogSubscriber
is an object set to consume ActiveSupport::Notifications with the sole purpose of logging them. The log subscriber dispatches notifications to a registered object based on its given namespace.
An example would be Active Record log subscriber responsible for logging queries:
module ActiveRecord
class LogSubscriber < ActiveSupport::LogSubscriber
def sql(event)
info "#{event.payload[:name]} (#{event.duration}) #{event.payload[:sql]}"
end
end
end
And it’s finally registered as:
ActiveRecord::LogSubscriber.attach_to :active_record
Since we need to know all instance methods before attaching the log subscriber, the line above should be called after your ActiveRecord::LogSubscriber
definition.
A logger also needs to be set with ActiveRecord::LogSubscriber.logger=
. This is assigned automatically in a Rails environment.
After configured, whenever a "sql.active_record"
notification is published, it will properly dispatch the event (ActiveSupport::Notifications::Event
) to the sql method.
Being an ActiveSupport::Notifications consumer, ActiveSupport::LogSubscriber
exposes a simple interface to check if instrumented code raises an exception. It is common to log a different message in case of an error, and this can be achieved by extending the previous example:
module ActiveRecord
class LogSubscriber < ActiveSupport::LogSubscriber
def sql(event)
exception = event.payload[:exception]
if exception
exception_object = event.payload[:exception_object]
error "[ERROR] #{event.payload[:name]}: #{exception.join(', ')} " \
"(#{exception_object.backtrace.first})"
else
# standard logger code
end
end
end
end
Log subscriber also has some helpers to deal with logging and automatically flushes all logs when the request finishes (via action_dispatch.callback
notification) in a Rails environment.
Direct Known Subclasses
Defined Under Namespace
Modules: TestHelper
Constant Summary collapse
- CLEAR =
Embed in a String to clear all previous ANSI sequences.
"\e[0m"
- BOLD =
"\e[1m"
- BLACK =
Colors
"\e[30m"
- RED =
"\e[31m"
- GREEN =
"\e[32m"
- YELLOW =
"\e[33m"
- BLUE =
"\e[34m"
- MAGENTA =
"\e[35m"
- CYAN =
"\e[36m"
- WHITE =
"\e[37m"
Class Attribute Summary collapse
Attributes inherited from Subscriber
Class Method Summary collapse
-
.flush_all! ⇒ Object
Flush all log_subscribers’ logger.
- .log_subscribers ⇒ Object
Instance Method Summary collapse
- #finish(name, id, payload) ⇒ Object
- #logger ⇒ Object
- #publish_event(event) ⇒ Object
- #start(name, id, payload) ⇒ Object
Methods inherited from Subscriber
attach_to, detach_from, #initialize, method_added, subscribers
Constructor Details
This class inherits a constructor from ActiveSupport::Subscriber
Class Attribute Details
.logger ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 83 def logger @logger ||= if defined?(Rails) && Rails.respond_to?(:logger) Rails.logger end end |
Class Method Details
.flush_all! ⇒ Object
Flush all log_subscribers’ logger.
96 97 98 |
# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 96 def flush_all! logger.flush if logger.respond_to?(:flush) end |
.log_subscribers ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 91 def log_subscribers subscribers end |
Instance Method Details
#finish(name, id, payload) ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 114 def finish(name, id, payload) super if logger rescue => e log_exception(name, e) end |
#logger ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 106 def logger LogSubscriber.logger end |
#publish_event(event) ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 120 def publish_event(event) super if logger rescue => e log_exception(event.name, e) end |
#start(name, id, payload) ⇒ Object
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/log_subscriber.rb', line 110 def start(name, id, payload) super if logger end |