COREDNS-ERRORS(7)

NAME

errors - enables error logging.

DESCRIPTION

Any errors encountered during the query processing will be printed to standard output. The errors of particular type can be consolidated and printed once per some period of time.

This plugin can only be used once per Server Block.

SYNTAX

The basic syntax is:

    errors

Extra knobs are available with an expanded syntax:

    errors {
        stacktrace
        consolidate DURATION REGEXP [LEVEL] [show_first]
    }

Option stacktrace will log a stacktrace during panic recovery.

Option consolidate allows collecting several error messages matching the regular expression REGEXP during DURATION. REGEXP must not exceed 10000 characters. After the DURATION since receiving the first such message, the consolidated message will be printed to standard output with log level, which is configurable by optional option LEVEL. Supported options for LEVEL option are warning,error,info and debug.

    2 errors like '^read udp .* i/o timeout$' occurred in last 30s

If the optional show_first flag is specified, the first error will be logged immediately when it occurs, and then subsequent matching errors will be consolidated. When the consolidation period ends: - If only one error occurred, no summary is printed (since it was already logged) - If multiple errors occurred, a summary is printed showing the total count

Example with 3 errors:

    [WARNING] 2 example.org. A: read udp 10.0.0.1:53->8.8.8.8:53: i/o timeout
    [WARNING] 3 errors like '^read udp .* i/o timeout$' occurred in last 30s

Example with 1 error:

    [WARNING] 2 example.org. A: read udp 10.0.0.1:53->8.8.8.8:53: i/o timeout

Multiple consolidate options with different DURATION and REGEXP are allowed. In case if some error message corresponds to several defined regular expressions the message will be associated with the first appropriate REGEXP.

For better performance, it's recommended to use the ^ or $ metacharacters in regular expression when filtering error messages by prefix or suffix, e.g. ^failed to .*, or .* timeout$.

EXAMPLES

Use the whoami to respond to queries in the example.org domain and Log errors to standard output.

    example.org {
        whoami
        errors
    }

Use the forward plugin to resolve queries via 8.8.8.8 and print consolidated messages for errors with suffix " i/o timeout" as warnings, and errors with prefix "Failed to " as errors.

    . {
        forward . 8.8.8.8
        errors {
            consolidate 5m ".* i/o timeout$" warning
            consolidate 30s "^Failed to .+"
        }
    }

Use the forward plugin and consolidate timeout errors with show_first option to see both the summary and the first occurrence of the error:

    . {
        forward . 8.8.8.8
        errors {
            consolidate 5m ".* i/o timeout$" warning show_first
            consolidate 30s "^Failed to .+" error show_first
        }
    }