The Grep Filter plugin allows to match or exclude specific records based in regular expression patterns.
The plugin supports the following configuration parameters:
Keep records which field matches the regular expression.
Exclude records which field matches the regular expression.
In order to start filtering records, you can run the filter from the command line or through the configuration file. The following example assumes that you have a file called lines.txt with the following content
Note: using the command line mode need special attention to quote the regular expressions properly. It's suggested to use a configuration file.
The following command will load the tail plugin and read the content of lines.txt file. Then the grep filter will apply a regular expression rule over the log field (created by tail plugin) and only pass the records which field value starts with aa:
$ bin/fluent-bit -i tail -p 'path=lines.txt' -F grep -p 'regex=log aa' -m '*' -o stdout
Regex log aa
The filter allows to use multiple rules which are applied in order, you can have many Regex and Exclude entries as required.
Currently nested fields are not supported. If you have records in the following format
and if you want to exclude records that match given nested field (for example
kubernetes.labels.app), you could use combination of nest and grep filters. Here is an example that will exclude records that match
Exclude app myapp