Configure the Ruby microagent

The Sqreen Microagent reads three sources for its configuration. It follows the configurations from these sources in sequence. The order of precedence is as follows:

  1. environment variables
  2. sqreen.yml file
  3. default configuration options

Configuration variables

The table below lists the variables you can use to customize the Sqreen microagent's configuration.

Environment variable name Role YAML key name Default value Allowed values
SQREEN_TOKEN The token is the identifier the Sqreen Platform uses to identify the microagent. Access your token in Account Settings > Environments & Tokens. token empty string
SQREEN_APP_NAME The application name as displayed on the Sqreen Dashboard. When using Rails, the application name derives from Rails's application class name. app_name empty (autodetected with Rails) string
SQREEN_CONFIG_FILE Specifies a custom location for the YAML-based config file. empty
SQREEN_LOG_LOCATION Specifies a custom file to which the microagent writes logs. log_location log/sqreen.log string
SQREEN_LOG_LEVEL Sets the microagent logging level. log_level WARN FATAL ERROR WARN INFO DEBUG
HTTP_PROXY, http_proxy Specifies an HTTP proxy server for the microagent's connection to the Sqreen Platform. http_proxy empty proxy URI (http://proxy:port)
SQREEN_REPORT_PERF Reports overhead for each request in the log (WARN level). report_perf false (disabled) boolean
SQREEN_REPORT_PERF_NR Reports overhead for each request to NewRelic as custom transaction attributes. report_perf_newrelic 0 (disabled) 0 (disabled), 1 (global overhead), 2 (report duration for each protection category)
SQREEN_IP_HEADER Specifies the header to use to extract the real IP address of a client. ip_header empty header name (case insensitive)
SQREEN_DISABLE Prevents the Sqreen agent from starting. Any value in this environment variable disables Sqreen. disable false (Sqreen is enabled) boolean
SQREEN_STRIP_SENSITIVE_DATA Removes sensitive data, including personally identifiable information (PII), before the microagent sends metadata to the Sqreen Platform. Refer to Sensitive data scrubbing below for details. strip_sensitive_data 1 (enabled) 1 (enabled), 0 (disabled)
SQREEN_STRIP_SENSITIVE_REGEX Regular expression that removes specific sensitive information before the microagent sends metadata to the Sqreen Platform. Refer to Sensitive data scrubbing below for details. strip_sensitive_regex empty (uses default values) (arbitrary)
SQREEN_STRIP_SENSITIVE_KEYS Comma-separated list of keys that removes specific sensitive information before the microagent sends metadata to the Sqreen Platform. Refer to Sensitive data scrubbing below for details. strip_sensitive_keys empty (uses default values) (arbitrary)

YAML file

The Sqreen Microagent stores configurations in the sqreen.yml file. The microagent detects the application root based on its installation folder. Save the sqreen.yml file in the top level folder in your application.

If you wish, you can customize a location for the YAML file. Use the SQREEN_CONFIG_FILE environment variable to specify a custom location in your application's directory.

export SQREEN_CONFIG_FILE=/custom/path/sqreen.yml
When you edit the sqreen.yaml configuration file, be sure to indent with two spaces. If you do not indent correctly, the Sqreen microagent throws an error at startup: Unable to parse configuration file.

Multiple Rails environments

The sqreen.yml configuration file enables you to use a different section per Rails environment.

token: mysecrettoken #general configuration

    token:  mysecretproductiontoken # override general configuration

Sensitive data scrubbing

The microagent does not send sensitive data, including Personally Identifiable Information (PII), to the Sqreen Platform. With each heartbeat, the microagent scrubs the metadata to remove sensitive data and replace any instances with Redacted by Sqreen.

By default, the microagent scrubs the following values from the metadata it sends:

  • Values that look like they contain credit card numbers, according to a basic regular expression: ^(?:\d[ -]*?){13,16}$
  • Values associated with any of the following keys:
    • password
    • secret
    • passwd
    • authorization
    • api_key
    • apikey
    • access_token

Turn off sensitive data scrubbing

To turn off sensitive data scrubbing, in the sqreen.yml file, set strip_sensitive_data to 0 (disabled).

Customize sensitive data scrubbing

You can customize the sensitive data that the microagent redacts.

  1. In the sqreen.yml file, use strip_sensitive_keys to replace the default values (case insensitive) that the microagent redacts.

  2. In the sqreen.yml file, use strip_sensitive_regex to replace the default values, including arrays, that match a regular expression. Be aware that adding a large number of regular expressions to this configuration may affect the application's performance.

Replace, not add

Be aware that the values you set in strip_sensitive_keys and strip_sensitive_regex replace the default values that the microagent redacts. In other words, the values you configure here are not added to the default values the microagent redacts, they override them