Nest
The Nest filter plugin lets you operate on or with nested data. Its modes of operation are:
nest
: Take a set of records and place them in a map.lift
Take a map by key and lift its records up.
Example usage for nest
nest
As an example using JSON notation, to nest keys matching the Wildcard
value Key*
under a new key NestKey
the transformation becomes:
Input:
{
"Key1" : "Value1",
"Key2" : "Value2",
"OtherKey" : "Value3"
}
Output:
{
"OtherKey" : "Value3"
"NestKey" : {
"Key1" : "Value1",
"Key2" : "Value2",
}
}
Example usage for lift
lift
As an example using JSON notation, to lift keys nested under the Nested_under
valueNestKey*
the transformation becomes:
Input:
{
"OtherKey" : "Value3"
"NestKey" : {
"Key1" : "Value1",
"Key2" : "Value2",
}
}
Output:
{
"Key1" : "Value1",
"Key2" : "Value2",
"OtherKey" : "Value3"
}
Configuration parameters
The plugin supports the following configuration parameters:
Operation
ENUM [nest
or lift
]
Select the operation nest
or lift
Wildcard
FIELD WILDCARD
nest
Nest records which field matches the wildcard
Nest_under
FIELD STRING
nest
Nest records matching the Wildcard
under this key
Nested_under
FIELD STRING
lift
Lift records nested under the Nested_under
key
Add_prefix
FIELD STRING
Any
Prefix affected keys with this string
Remove_prefix
FIELD STRING
Any
Remove prefix from affected keys if it matches this string
Get started
To start filtering records, run the filter from the command line or through the configuration file. The following example invokes the Memory Usage input plugin, which outputs the following:
[0] memory: [1488543156, {"Mem.total"=>1016044, "Mem.used"=>841388, "Mem.free"=>174656, "Swap.total"=>2064380, "Swap.used"=>139888, "Swap.free"=>1924492}]
Example 1 - nest
Use nest
from the command line
nest
from the command lineUsing the command line mode requires quotes to parse the wildcard properly. The use of a configuration file is recommended.
The following command loads the mem plugin. Then the nest filter matches the
wildcard rule to the keys and nests the keys matching Mem.*
under the new keyNEST
.
bin/fluent-bit -i mem -p 'tag=mem.local' -F nest -p 'Operation=nest' -p 'Wildcard=Mem.*' -p 'Nest_under=Memstats' -p 'Remove_prefix=Mem.' -m '*' -o stdout
Nest configuration file
[INPUT]
Name mem
Tag mem.local
[OUTPUT]
Name stdout
Match *
[FILTER]
Name nest
Match *
Operation nest
Wildcard Mem.*
Nest_under Memstats
Remove_prefix Mem.
Nest 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: [1522978514.007359767, {"Swap.total"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Memstats"=>{"total"=>4050908, "used"=>714984, "free"=>3335924}}]
Example 2 - nest
and lift
undo
nest
and lift
undoThis example nests all Mem.*
and Swap.*
items under the Stats
key and then reverses these actions with a lift
operation. The output appears unchanged.
nest
and lift
undo configuration file
nest
and lift
undo configuration file[INPUT]
Name mem
Tag mem.local
[OUTPUT]
Name stdout
Match *
[FILTER]
Name nest
Match *
Operation nest
Wildcard Mem.*
Wildcard Swap.*
Nest_under Stats
Add_prefix NESTED
[FILTER]
Name nest
Match *
Operation lift
Nested_under Stats
Remove_prefix NESTED
nest
and lift
undo result
nest
and lift
undo result[2018/06/21 17:42:37] [ info] [engine] started (pid=17285)
[0] mem.local: [1529566958.000940636, {"Mem.total"=>8053656, "Mem.used"=>6940380, "Mem.free"=>1113276, "Swap.total"=>16532988, "Swap.used"=>1286772, "Swap.free"=>15246216}]
Example 3 - nest
3 levels deep
nest
3 levels deepThis example takes the keys starting with Mem.*
and nests them under LAYER1
,
which is then nested under LAYER2
, which is nested under LAYER3
.
Deep nest
configuration file
nest
configuration file[INPUT]
Name mem
Tag mem.local
[OUTPUT]
Name stdout
Match *
[FILTER]
Name nest
Match *
Operation nest
Wildcard Mem.*
Nest_under LAYER1
[FILTER]
Name nest
Match *
Operation nest
Wildcard LAYER1*
Nest_under LAYER2
[FILTER]
Name nest
Match *
Operation nest
Wildcard LAYER2*
Nest_under LAYER3
Deep nest
Result
nest
Result[0] mem.local: [1524795923.009867831, {"Swap.total"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "LAYER3"=>{"LAYER2"=>{"LAYER1"=>{"Mem.total"=>4050908, "Mem.used"=>1112036, "Mem.free"=>2938872}}}}]
{
"Swap.total"=>1046524,
"Swap.used"=>0,
"Swap.free"=>1046524,
"LAYER3"=>{
"LAYER2"=>{
"LAYER1"=>{
"Mem.total"=>4050908,
"Mem.used"=>1112036,
"Mem.free"=>2938872
}
}
}
}
Example 4 - multiple nest
and lift
filters with prefix
nest
and lift
filters with prefixThis example uses the 3-level deep nesting of Example 2 and applies the lift
filter three times to reverse the operations. The end result is that all records are at the top level, without nesting, again. One prefix is added for each level that's lifted.
nest
and lift
prefix configuration file
nest
and lift
prefix configuration file[INPUT]
Name mem
Tag mem.local
[OUTPUT]
Name stdout
Match *
[FILTER]
Name nest
Match *
Operation nest
Wildcard Mem.*
Nest_under LAYER1
[FILTER]
Name nest
Match *
Operation nest
Wildcard LAYER1*
Nest_under LAYER2
[FILTER]
Name nest
Match *
Operation nest
Wildcard LAYER2*
Nest_under LAYER3
[FILTER]
Name nest
Match *
Operation lift
Nested_under LAYER3
Add_prefix Lifted3_
[FILTER]
Name nest
Match *
Operation lift
Nested_under Lifted3_LAYER2
Add_prefix Lifted3_Lifted2_
[FILTER]
Name nest
Match *
Operation lift
Nested_under Lifted3_Lifted2_LAYER1
Add_prefix Lifted3_Lifted2_Lifted1_
nest
and lift
prefix result
nest
and lift
prefix result[0] mem.local: [1524862951.013414798, {"Swap.total"=>1046524, "Swap.used"=>0, "Swap.free"=>1046524, "Lifted3_Lifted2_Lifted1_Mem.total"=>4050908, "Lifted3_Lifted2_Lifted1_Mem.used"=>1253912, "Lifted3_Lifted2_Lifted1_Mem.free"=>2796996}]
{
"Swap.total"=>1046524,
"Swap.used"=>0,
"Swap.free"=>1046524,
"Lifted3_Lifted2_Lifted1_Mem.total"=>4050908,
"Lifted3_Lifted2_Lifted1_Mem.used"=>1253912,
"Lifted3_Lifted2_Lifted1_Mem.free"=>2796996
}
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