Modify

The Modify Filter plugin allows you to change records using rules and conditions.

Example usage

As an example using JSON notation to,

• Rename Key2 to RenamedKey

• Add a key OtherKey with value Value3 if OtherKey does not yet exist

Example (input)

{
  "Key1"     : "Value1",
  "Key2"     : "Value2"
}

Example (output)

{
  "Key1"       : "Value1",
  "RenamedKey" : "Value2",
  "OtherKey"   : "Value3"
}

Configuration Parameters

Rules

The plugin supports the following rules:

Operation	Parameter 1	Parameter 2	Description
Set	STRING:KEY	STRING:VALUE	Add a key/value pair with key KEY and value VALUE. If KEY already exists, this field is overwritten
Add	STRING:KEY	STRING:VALUE	Add a key/value pair with key KEY and value VALUE if KEY does not exist
Remove	STRING:KEY	NONE	Remove a key/value pair with key KEY if it exists
Remove_wildcard	WILDCARD:KEY	NONE	Remove all key/value pairs with key matching wildcard KEY
Remove_regex	REGEXP:KEY	NONE	Remove all key/value pairs with key matching regexp KEY
Rename	STRING:KEY	STRING:RENAMED_KEY	Rename a key/value pair with key KEY to RENAMED_KEY if KEY exists AND RENAMED_KEY does not exist
Hard_rename	STRING:KEY	STRING:RENAMED_KEY	Rename a key/value pair with key KEY to RENAMED_KEY if KEY exists. If RENAMED_KEY already exists, this field is overwritten
Copy	STRING:KEY	STRING:COPIED_KEY	Copy a key/value pair with key KEY to COPIED_KEY if KEY exists AND COPIED_KEY does not exist
Hard_copy	STRING:KEY	STRING:COPIED_KEY	Copy a key/value pair with key KEY to COPIED_KEY if KEY exists. If COPIED_KEY already exists, this field is overwritten
Move_to_start	WILDCARD:KEY	NONE	Move key/value pairs with keys matching KEY to the start of the message
Move_to_end	WILDCARD:KEY	NONE	Move key/value pairs with keys matching KEY to the end of the message

• Rules are case insensitive, parameters are not

• Any number of rules can be set in a filter instance.

• Rules are applied in the order they appear, with each rule operating on the result of the previous rule.

Conditions

The plugin supports the following conditions:

Condition	Parameter	Parameter 2	Description
Key_exists	STRING:KEY	NONE	Is true if KEY exists
Key_does_not_exist	STRING:KEY	NONE	Is true if KEY does not exist
A_key_matches	REGEXP:KEY	NONE	Is true if a key matches regex KEY
No_key_matches	REGEXP:KEY	NONE	Is true if no key matches regex KEY
Key_value_equals	STRING:KEY	STRING:VALUE	Is true if KEY exists and its value is VALUE
Key_value_does_not_equal	STRING:KEY	STRING:VALUE	Is true if KEY exists and its value is not VALUE
Key_value_matches	STRING:KEY	REGEXP:VALUE	Is true if key KEY exists and its value matches VALUE
Key_value_does_not_match	STRING:KEY	REGEXP:VALUE	Is true if key KEY exists and its value does not match VALUE
Matching_keys_have_matching_values	REGEXP:KEY	REGEXP:VALUE	Is true if all keys matching KEY have values that match VALUE
Matching_keys_do_not_have_matching_values	REGEXP:KEY	REGEXP:VALUE	Is true if all keys matching KEY have values that do not match VALUE

• Conditions are case insensitive, parameters are not

• Any number of conditions can be set.

• Conditions apply to the whole filter instance and all its rules. Not to individual rules.

• All conditions have to be true for the rules to be applied.

• You can set Record Accessor as STRING:KEY for nested key.

Example #1 - Add and Rename

In order to start filtering records, you can run the filter from the command line or through the configuration file. The following invokes the Memory Usage Input Plugin, which outputs the following (example),

[0] memory: [1488543156, {"Mem.total"=>1016044, "Mem.used"=>841388, "Mem.free"=>174656, "Swap.total"=>2064380, "Swap.used"=>139888, "Swap.free"=>1924492}]
[1] memory: [1488543157, {"Mem.total"=>1016044, "Mem.used"=>841420, "Mem.free"=>174624, "Swap.total"=>2064380, "Swap.used"=>139888, "Swap.free"=>1924492}]
[2] memory: [1488543158, {"Mem.total"=>1016044, "Mem.used"=>841420, "Mem.free"=>174624, "Swap.total"=>2064380, "Swap.used"=>139888, "Swap.free"=>1924492}]
[3] memory: [1488543159, {"Mem.total"=>1016044, "Mem.used"=>841420, "Mem.free"=>174624, "Swap.total"=>2064380, "Swap.used"=>139888, "Swap.free"=>1924492}]

Using command Line

Note: Using the command line mode requires quotes parse the wildcard properly. The use of a configuration file is recommended.

bin/fluent-bit -i mem \
  -p 'tag=mem.local' \
  -F modify \
  -p 'Add=Service1 SOMEVALUE' \
  -p 'Add=Service2 SOMEVALUE3' \
  -p 'Add=Mem.total2 TOTALMEM2' \
  -p 'Rename=Mem.free MEMFREE' \
  -p 'Rename=Mem.used MEMUSED' \
  -p 'Rename=Swap.total SWAPTOTAL' \
  -p 'Add=Mem.total TOTALMEM' \
  -m '*' \
  -o stdout

Configuration File

fluent-bit.conf

[INPUT]
    Name mem
    Tag  mem.local

[OUTPUT]
    Name  stdout
    Match *

[FILTER]
    Name modify
    Match *
    Add Service1 SOMEVALUE
    Add Service3 SOMEVALUE3
    Add Mem.total2 TOTALMEM2
    Rename Mem.free MEMFREE
    Rename Mem.used MEMUSED
    Rename Swap.total SWAPTOTAL
    Add Mem.total TOTALMEM

fluent-bit.yaml

pipeline:
    inputs:
        - name: mem
          tag: mem.local
    filters:
        - name: modify
          match: '*'
          Add:
            - Service1 SOMEVALUE
            - Service3 SOMEVALUE3
            - Mem.total2 TOTALMEM2
            - Mem.total TOTALMEM
          Rename:
            - Mem.free MEMFREE
            - Mem.used MEMUSED
            - Swap.total SWAPTOTAL
    outputs:
        - name: stdout
          match: '*'

Result

The output of both the command line and configuration invocations should be identical and result in the following output.

[2018/04/06 01:35:13] [ info] [engine] started
[0] mem.local: [1522980610.006892802, {"Mem.total"=>4050908, "MEMUSED"=>738100, "MEMFREE"=>3312808, "SWAPTOTAL"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Service1"=>"SOMEVALUE", "Service3"=>"SOMEVALUE3", "Mem.total2"=>"TOTALMEM2"}]
[1] mem.local: [1522980611.000658288, {"Mem.total"=>4050908, "MEMUSED"=>738068, "MEMFREE"=>3312840, "SWAPTOTAL"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Service1"=>"SOMEVALUE", "Service3"=>"SOMEVALUE3", "Mem.total2"=>"TOTALMEM2"}]
[2] mem.local: [1522980612.000307652, {"Mem.total"=>4050908, "MEMUSED"=>738068, "MEMFREE"=>3312840, "SWAPTOTAL"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Service1"=>"SOMEVALUE", "Service3"=>"SOMEVALUE3", "Mem.total2"=>"TOTALMEM2"}]
[3] mem.local: [1522980613.000122671, {"Mem.total"=>4050908, "MEMUSED"=>738068, "MEMFREE"=>3312840, "SWAPTOTAL"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Service1"=>"SOMEVALUE", "Service3"=>"SOMEVALUE3", "Mem.total2"=>"TOTALMEM2"}]

Example #2 - Conditionally Add and Remove

Configuration File

fluent-bit.conf

[INPUT]
    Name mem
    Tag  mem.local
    Interval_Sec 1

[FILTER]
    Name    modify
    Match   mem.*

    Condition Key_Does_Not_Exist cpustats
    Condition Key_Exists Mem.used

    Set cpustats UNKNOWN

[FILTER]
    Name    modify
    Match   mem.*

    Condition Key_Value_Does_Not_Equal cpustats KNOWN

    Add sourcetype memstats

[FILTER]
    Name    modify
    Match   mem.*

    Condition Key_Value_Equals cpustats UNKNOWN

    Remove_wildcard Mem
    Remove_wildcard Swap
    Add cpustats_more STILL_UNKNOWN

[OUTPUT]
    Name           stdout
    Match          *

fluent-bit.yaml

pipeline:
    inputs:
        - name: mem
          tag: mem.local
          interval_sec: 1
    filters:
        - name: modify
          match: mem.*
          Condition:
            - Key_Does_Not_Exist cpustats
            - Key_Exists Mem.used
          Set: cpustats UNKNOWN
        - name: modify
          match: mem.*
          Condition: Key_Value_Does_Not_Equal cpustats KNOWN
          Add: sourcetype memstats
        - name: modify
          match: mem.*
          Condition: Key_Value_Equals cpustats UNKNOWN
          Remove_wildcard:
            - Mem
            - Swap
          Add: cpustats_more STILL_UNKNOWN
    outputs:
        - name: stdout
          match: '*'

Result

[2018/06/14 07:37:34] [ info] [engine] started (pid=1493)
[0] mem.local: [1528925855.000223110, {"cpustats"=>"UNKNOWN", "sourcetype"=>"memstats", "cpustats_more"=>"STILL_UNKNOWN"}]
[1] mem.local: [1528925856.000064516, {"cpustats"=>"UNKNOWN", "sourcetype"=>"memstats", "cpustats_more"=>"STILL_UNKNOWN"}]
[2] mem.local: [1528925857.000165965, {"cpustats"=>"UNKNOWN", "sourcetype"=>"memstats", "cpustats_more"=>"STILL_UNKNOWN"}]
[3] mem.local: [1528925858.000152319, {"cpustats"=>"UNKNOWN", "sourcetype"=>"memstats", "cpustats_more"=>"STILL_UNKNOWN"}]

Example #3 - Emoji

Configuration File

fluent-bit.conf

[INPUT]
    Name mem
    Tag  mem.local

[OUTPUT]
    Name  stdout
    Match *

[FILTER]
    Name modify
    Match *

    Remove_Wildcard Mem
    Remove_Wildcard Swap
    Set This_plugin_is_on 🔥
    Set 🔥 is_hot
    Copy 🔥 💦
    Rename  💦 ❄️
    Set ❄️ is_cold
    Set 💦 is_wet

fluent-bit.yaml

pipeline:
    inputs:
        - name: mem
          tag: mem.local
          interval_sec: 1
    filters:
        - name: modify
          match: mem.*
          Remove_wildcard:
            - Mem
            - Swap
          Set:
            - This_plugin_is_on 🔥
            - 🔥 is_hot
          Copy: 🔥 💦
          Rename:  💦 ❄️
          Set:
            - ❄️ is_cold
            - 💦 is_wet
    outputs:
        - name: stdout
          match: '*'

Result

[2018/06/14 07:46:11] [ info] [engine] started (pid=21875)
[0] mem.local: [1528926372.000197916, {"This_plugin_is_on"=>"🔥", "🔥"=>"is_hot", "❄️"=>"is_cold", "💦"=>"is_wet"}]
[1] mem.local: [1528926373.000107868, {"This_plugin_is_on"=>"🔥", "🔥"=>"is_hot", "❄️"=>"is_cold", "💦"=>"is_wet"}]
[2] mem.local: [1528926374.000181042, {"This_plugin_is_on"=>"🔥", "🔥"=>"is_hot", "❄️"=>"is_cold", "💦"=>"is_wet"}]
[3] mem.local: [1528926375.000090841, {"This_plugin_is_on"=>"🔥", "🔥"=>"is_hot", "❄️"=>"is_cold", "💦"=>"is_wet"}]
[0] mem.local: [1528926376.000610974, {"This_plugin_is_on"=>"🔥", "🔥"=>"is_hot", "❄️"=>"is_cold", "💦"=>"is_wet"}]