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This documentation outlines how to configure logging with the AppSignal for Elixir integration.

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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 Elixir integration. An “application” log source will be created automatically.

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Logger Handler

You can configure the Erlang :logger to use the Appsignal.Logger.Handler module as a handler, by calling the Appsignal.Logger.Handler.add/2 function on your Application.start/2 callback: 
@impl true
def start(_type, _args) do
  Appsignal.Logger.Handler.add("phoenix")
end
The given argument is the group name that describes where you are logging from. This group name can be used in AppSignal to filter your logs.

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Logger Backend

Starting with Elixir version 1.15, Elixir logger backends are no longer recommended. See the Logger Handler section above for the recommended alternative.
Instead of using an Elixir logger handler, you can configure the Elixir logger backend to use the Appsignal.Logger.Backend module as a backend by placing the code below in the config/runtime.exs file: 
config :logger, backends: [:console, {Appsignal.Logger.Backend, [group: "phoenix"]}]
The group option describes where you are logging from. This group name can be used in AppSignal to filter your logs. You can also add the backend using the add_backend/2 function on your Application.start/2 callback: 
@impl true
def start(_type, _args) do
  Logger.add_backend(Appsignal.Logger.Backend, group: "phoenix")
end

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Elixir Logger

To send logs to AppSignal without using the Elixir Logger backend, you can use one of Appsignal.Logger’s logging functions 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: 
Appsignal.Logger.info(
  "invoice_helper",
  "Generating invoice for customer 129"
)

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Usage

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Sending Logs

Like the Elixir/Phoenix logger class, you can define the severity level of your logs by using fatal, error, warning, info, and debug: 
Appsignal.Logger.warning(
  "app",
  "Something's gone terribly wrong here"
)
You can pass custom attributes as the last argument, to send log information that can be used when filtering and querying logs: 
Appsignal.Logger.info(
  "invoice_helper",
  "Generated invoice for customer #{customer.id}",
  %{ 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.

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Formats

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Auto detected format

The AppSignal for Elixir package 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. 
# Plaintext format
Appsignal.Logger.info(
  "invoice_helper",
  "Generated invoice"
)
# Logfmt format
Appsignal.Logger.info(
  "invoice_helper",
  "Generated invoice invoice_id=A145 for customer customer_id=123"
)
# JSON format
Appsignal.Logger.info(
  "invoice_helper",
  ~s({"message": "Generated invoice for customer", "invoice_id": "A145", "customer_id": "123"})
)

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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 Elixir package version, which does not support automatic format detection. The Logfmt format can be specified when the AppSignal logger is called by adding the :logfmt value as the last argument. 
Appsignal.Logger.info(
  "invoice_helper",
  "Generated invoice invoice_id=A145 for customer customer_id=123",
  :logfmt
)

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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 Elixir package version, which does not support automatic format detection. The JSON format can be specified when the AppSignal logger is called by adding the :json value as the last argument. 
Appsignal.Logger.info(
  "invoice_helper",
  ~s({"message": "Generated invoice for customer", "invoice_id": "A145", "customer_id": "123"}),
  :json
)
Only primitive non-nested values (numbers, strings, booleans and null) will be shown as log attributes. All other attributes will be discarded.

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Filtering Logs

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

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Need Help?

After configuring your Elixir 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!