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log-transformations.md

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description
This page explains what log message transformations are available in Aidbox

Log transformations

What is log transformation?

Transformation is the tool used to modify and/or filter log messages on the fly according to the rules defined in the Aidbox configuration.

How transformation can be activated

To active transformations on an appender define the transformation and add it to the appender. In the example below there are two transformation applied to the :qb/q log messages and aidbox.log/ignore transformation applied to the :w/resp messages.

{:ns     main
 :import #{aidbox
           aidbox.log
           config}

 db-q-transform
 {:zen/tags #{aidbox.log/transform}
  :transforms
   [{:filter {:path [:d] :op :min :value 100}}
    {:trim {:path [:sql] :length 50}}]}

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:qb/q db-q-transform
               :w/resp aidbox.log/ignore}}

 box
 {:zen/tags #{aidbox/system}
  :config   config/zen-config
  :services {:seed            config/admin-seed
             :stdout-appender stdout-appender}}}

aidbox.log/ignore

To ignore the all the messages related to a certain type use built-in aidbox.log/ignore transformation. In the example below all the :w/resp (http response) messages are skipped.

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:w/resp aidbox.log/ignore}}

:filter

Decides whether to omit a log message. It compares the threshold value with the specified path log value.

 only-slow-sql-queries-allowed
 {:zen/tags #{aidbox.log/transform}
  :transforms
   [{:filter {:path [:d] :op :min :value 100}}]}

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:qb/q only-slow-sql-queries-allowed}}

This example transformation skips log messages where the d property in a message is lower than 100.

Parameters

  • :op defines the operation:
    • :min skips a message when threshold is lower than specified path value
    • :max skips a message when threshold is greater than specified path value
  • :value is the threshold
  • :path specifies the path in the message where the desired value is held

:trim

Overwrites the given path value with the sub-string function.

 sql-shorter-than-50-chars
 {:zen/tags #{aidbox.log/transform}
  :transforms
   [{:trim {:path [:sql] :length 50}}]}

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:qb/q sql-shorter-than-50-chars}}

This example transformation reduces the length of the :sql string if it is longer than 50 symbols.

Parameters

  • :length defines the maximum allowed string length
  • :path specifies where the desired string should be taken from

:dissoc

Removes the given keys set from the root of the log message.

 no-sql-params
 {:zen/tags #{aidbox.log/transform}
  :transforms
   [{:dissoc [:db_prm]}]}

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:qb/q no-sql-params}}

This transformation remove the key :db_prm and its values from the log message.

Parameters

:dissoc itself is an array of prohibited root keys.

:select-keys

Takes defined keys from the root of the log message.

 whitelisted-sql-keys
 {:zen/tags #{aidbox.log/transform}
  :transforms
   [{:select-keys [:ev :op :ts :sql :d]}]}

 stdout-appender
 {:zen/tags #{aidbox/service}
  :engine   aidbox.log/stdout-appender
  :transforms {:qb/q whitelisted-sql-keys}}

This transformation omits all the keys in a log messaged except: :ev, :op, :sql and :d.

Parameters

:select-keys itself is an array of whitelisted root keys.