Logging from Ruby

This documentation outlines how to configure logging with your AppSignal for Ruby integration.

Configure Logging

🔐 Do not send Personal Identifiable Information (PII) to AppSignal. Filter PII (e.g., names, emails) from logs and use an ID, hash, or pseudonymized identifier instead.

For HIPAA-covered entities, more information about signing a Business Associate Agreement (BAA) can be found in our Business Add-Ons documentation.

You do not need to create a log source to send logs from the AppSignal for Ruby integration. An “application” log source will be created automatically.

Rails Logger

You can configure the Rails framework to send logs to AppSignal in an initializer file like config/initializers/logging.rb:

# config/initializers/logging.rb
appsignal_logger = Appsignal::Logger.new("rails")
Rails.logger = ActiveSupport::TaggedLogging.new(appsignal_logger)

Using multiple logging backends

To send logs to both AppSignal’s logger and Rails’ default logger, use our logger’s .broadcast_to helper:

# config/initializers/logging.rb
appsignal_logger = Appsignal::Logger.new("rails")
appsignal_logger.broadcast_to(Rails.logger)
Rails.logger = ActiveSupport::TaggedLogging.new(appsignal_logger)

We do not recommend using Rails’ built-in broadcast logger feature, due to compatibility issues when used alongside tagged logging.

Tagged logging support

The use of ActiveSupport::TaggedLogging in the above examples enables support for Rails’ log tags. For example, if you wish to add the request ID tag to the log messages, add it to the config.log_tags array in the config/application.rb file:

module TestApp
  class Application < Rails::Application
    config.log_tags = [:request_id]
  end
end

Using Lograge

This Lograge config is not a replacement for the Rails logger config. If you want to report logs from Rails.logger, the Rails logger config steps also need to be followed.

The Lograge library is a popular solution for ingesting structured Rails request logs. After adding the lograge gem, you can configure it in config/initializers/lograge.rb to send logs to AppSignal:

Rails.application.configure do
  config.lograge.enabled = true
  config.lograge.keep_original_rails_log = true
  config.lograge.logger = Appsignal::Logger.new(
    "rails",
    format: Appsignal::Logger::LOGFMT
  )
end

Lograge does not support log levels. All logs emitted via Lograge will appear with severity level INFO in the AppSignal Logging UI.

Sinatra Logger

You can configure Sinatra to send request logs to AppSignal using Rack’s CommonLogger middleware. Configure it like shown below. Consider if request logs contain useful information for you, read our what logs should I store learning center article.

logger = Appsignal::Logger.new("sinatra")
use Rack::CommonLogger, logger

Using multiple logging backends

To send logs to both AppSignal’s logger and STDOUT, use our logger’s .broadcast_to helper:

logger = Appsignal::Logger.new("sinatra")
logger.broadcast_to(Logger.new($stdout))
use Rack::CommonLogger, logger

Sidekiq Logger

You can configure Sidekiq to send its logs to AppSignal, including the logs emitted by your background jobs:

Sidekiq.configure_server do |config|
  config.logger = Appsignal::Logger.new("sidekiq")
  config.logger.formatter = Sidekiq::Logger::Formatters::WithoutTimestamp.new
end

Using multiple logging backends

To send logs to both AppSignal’s logger and STDOUT, use our logger’s .broadcast_to helper:

Sidekiq.configure_server do |config|
  config.logger = Appsignal::Logger.new("sidekiq")
  config.logger.broadcast_to(Logger.new($stdout))
  config.logger.formatter = Sidekiq::Logger::Formatters::WithoutTimestamp.new
end

Ruby Logger

To send logs to AppSignal as you would with Ruby’s Logger class, you will need to create an instance of Appsignal::Logger and provide it with a groupname that defines where you are logging from, for example, if we were logging from a helper for invoicing clients:

logger = Appsignal::Logger.new("invoice_helper")

Using multiple logging backends

To send logs to both AppSignal’s logger and STDOUT, use our logger’s .broadcast_to helper:

logger = Appsignal::Logger.new("invoice_helper")
logger.broadcast_to(Logger.new($stdout))

Semantic Logger

The Semantic Logger library provides a comprehensive logging solution for Ruby and Rails applications. After adding the semantic_logger gem, you can configure it to send logs to AppSignal as follows:

appsignal_logger = Appsignal::Logger.new("rails", format: Appsignal::Logger::LOGFMT)
SemanticLogger.add_appender(logger: appsignal_logger, formatter: :logfmt)

Using multiple logging backends

To send logs to both AppSignal’s logger and STDOUT, add another appender using the add_appender method:

appsignal_logger = Appsignal::Logger.new("rails", format: Appsignal::Logger::LOGFMT)
SemanticLogger.add_appender(logger: appsignal_logger, formatter: :logfmt)
SemanticLogger.add_appender(io: $stdout)

Usage

Sending Logs

Like the Ruby/Rails Logger class, you can define the severity level of your logs by using fatal, error, warn, info, and debug:

logger.warn("Something went wrong")

You can define custom attributes to send log information that can be used when filtering and querying logs:

logger = Appsignal::Logger.new("invoice_helper")
logger.info("Generating invoice for customer", { customer_id: @customer.id })
invoice = generate_invoice(@customer)
logger.info("Generated invoice for customer", { customer_id: @customer.id, invoice_id: invoice.id })

You can query and filter on message contents and attribute values using our query syntax. Once configured, the desired attributes will be sent to AppSignal as log tags, and be queryable in the AppSignal logging interface.

Default Logger Attributes

When initializing the AppSignal logger, you can provide default attributes that will be included in all log messages:

logger = Appsignal::Logger.new("invoice_helper", attributes: { customer_id: @customer.id })

The attributes provided when initializing the logger will be included in all log messages sent from that logger instance. Attributes provided with the log message will be merged with the default logger attributes.

logger = Appsignal::Logger.new("invoice_helper", attributes: { customer_id: @customer.id })
# This log message will contain the `customer_id` attribute:
logger.info("Generating invoice for customer")

invoice = generate_invoice(@customer)
# This log message will contain the `customer_id` and `invoice_id` attributes:
logger.info("Generated invoice for customer", { invoice_id: invoice.id })

When both the logger and the log message provide the same attribute, the log message’s attribute will override the default logger attribute.

Formats

Auto detected format

The AppSignal for Ruby gem will automatically detect the log line’s format as JSON, Logfmt or plaintext by default, and parse attributes from it. You don’t need to manually set the log format, unless it’s not being detected properly. Please also notify us if this isn’t working automatically.

logger = Appsignal::Logger.new("group")
# Plaintext format
logger.info("This is about the blog")
# Logfmt format
logger.info("category=blog This is about the blog")
# JSON format
logger.info('{"category": "blog", "message": "This is about the blog"}')

Logfmt

The AppSignal Logger can be explicitly configured to expect the line to be formatted as Logfmt and parse attributes from it. Use this option when using an older AppSignal for Ruby gem version, which does not support automatic format detection. The log format can be specified when creating a logger. When initializing the AppSignal logger pass the Logfmt constant in the format option.

logger = Appsignal::Logger.new("group", format: Appsignal::Logger::LOGFMT)
logger.info("category=blog This is about the blog")

In the example above, a filterable category attribute with the value “blog” will be logged.

JSON

The AppSignal Logger can be explicitly configured to expect the line to be formatted as JSON and parse attributes from it. Use this option when using an older AppSignal for Ruby gem version, which does not support automatic format detection. The log format can be specified when creating a logger. When initializing the AppSignal logger pass the JSON constant in the format option.

logger = Appsignal::Logger.new("group", format: Appsignal::Logger::JSON)
logger.info('{"category": "blog", "message": "This is about the blog"}')

In the example above, a filterable category attribute with the value “blog” will be logged.

Filtering Logs

You can use the ignore_logs configuration option to ignore log lines. See our Ignore Logs guide to learn more.

Need Help?

After configuring your Ruby application to send logs, logs should appear in AppSignal. If you are unsure about this step or AppSignal is not receiving any logs, you can always reach out for assistance. We’ll help get you back on track!

Features

Application health

Logs & metrics

Infrastructure

Tuning your apps

Configure Logging

Rails Logger

Using multiple logging backends

Tagged logging support

Using Lograge

Sinatra Logger

Using multiple logging backends

Sidekiq Logger

Using multiple logging backends

Ruby Logger

Using multiple logging backends

Semantic Logger

Using multiple logging backends

Usage

Sending Logs

Default Logger Attributes

Formats

Auto detected format

Logfmt

JSON

Filtering Logs

Need Help?

​Configure Logging

​Rails Logger

​Using multiple logging backends

​Tagged logging support

​Using Lograge

​Sinatra Logger

​Using multiple logging backends

​Sidekiq Logger

​Using multiple logging backends

​Ruby Logger

​Using multiple logging backends

​Semantic Logger

​Using multiple logging backends

​Usage

​Sending Logs

​Default Logger Attributes

​Formats

​Auto detected format

​Logfmt

​JSON

​Filtering Logs

​Need Help?

Configure Logging

Rails Logger

Using multiple logging backends

Tagged logging support

Using Lograge

Sinatra Logger

Using multiple logging backends

Sidekiq Logger

Using multiple logging backends

Ruby Logger

Using multiple logging backends

Semantic Logger

Using multiple logging backends

Usage

Sending Logs

Default Logger Attributes

Formats

Auto detected format

Logfmt

JSON

Filtering Logs

Need Help?