decoder

Decoders

In pipeline settings there is a parameter for choosing desired decoding format. By default, every pipeline utilizes json decoder, which tries to parse json from log.

Some decoders support parameters, you can specify them in decoder_params.

Available values for decoder param:

• auto -- selects decoder type depending on input (e.g. for k8s input plugin, the decoder will be selected depending on container runtime version)
• json -- parses json format from log into event
• raw -- writes raw log into event message field
• cri -- parses cri format from log into event (e.g. 2016-10-06T00:17:09.669794203Z stderr F log content)
• postgres -- parses postgres format from log into event (e.g. 2021-06-22 16:24:27 GMT [7291] => [3-1] client=test_client,db=test_db,user=test_user LOG: listening on Unix socket \"/var/run/postgresql/.s.PGSQL.5432\"\n)
• nginx_error -- parses nginx error log format from log into event (e.g. 2022/08/17 10:49:27 [error] 2725122#2725122: *792412315 lua udp socket read timed out, context: ngx.timer)
• protobuf -- parses protobuf message into event
• syslog_rfc3164 -- parses syslog-RFC3164 format from log into event (see RFC3164)
• syslog_rfc5424 -- parses syslog-RFC5424 format from log into event (see RFC5424)
• csv -- parses csv format from log into event

Currently auto is available only for usage with k8s input plugin.

Json decoder

Params

• json_max_fields_size - map {path}: {limit} where {path} is path to field (cfg.FieldSelector) and {limit} is integer limit of the field length. If set, the fields will be cut to the specified limit.

  It works only with string values. If the field doesn't exist or isn't a string, it will be skipped.

Examples

Default decoder:

pipelines:
  example:
    settings:
      decoder: 'json'

From:

"{\"level\":\"error\",\"message\":\"error occurred\",\"ts\":\"2023-10-30T13:35:33.638720813Z\",\"stream\":\"stderr\"}"

To:

{
  "level": "error",
  "message": "error occurred",
  "ts": "2023-10-30T13:35:33.638720813Z",
  "stream": "stderr"
}

---

Decoder with json_max_fields_size param:

pipelines:
  example:
    settings:
      decoder: 'json'
      decoder_params:
        json_max_fields_size:
          level: 3
          message: 5
          ts: 10

From:

"{\"level\":\"error\",\"message\":\"error occurred\",\"ts\":\"2023-10-30T13:35:33.638720813Z\",\"stream\":\"stderr\"}"

To:

{
  "level": "err",
  "message": "error",
  "ts": "2023-10-30",
  "stream": "stderr"
}

Nginx-error decoder

The resulting event may contain any of the following fields:

• time string
• level string
• pid string
• tid string
• cid string
• message string

Params

• nginx_with_custom_fields - if set, custom fields will be extracted.

Examples

Default decoder:

pipelines:
  example:
    settings:
      decoder: 'nginx_error'

From:

2022/08/17 10:49:27 [error] 2725122#2725122: *792412315 lua udp socket read timed out, context: ngx.timer

To:

{
  "time": "2022/08/17 10:49:27",
  "level": "error",
  "pid": "2725122",
  "tid": "2725122",
  "cid": "792412315",
  "message": "lua udp socket read timed out, context: ngx.timer"
}

---

Decoder with nginx_with_custom_fields param:

pipelines:
  example:
    settings:
      decoder: 'nginx_error'
      decoder_params:
        nginx_with_custom_fields: true

From:

2022/08/18 09:29:37 [error] 844935#844935: *44934601 upstream timed out (110: Operation timed out), while connecting to upstream, client: 10.125.172.251, server: , request: "POST /download HTTP/1.1", upstream: "http://10.117.246.15:84/download", host: "mpm-youtube-downloader-38.name.tldn:84"

To:

{
  "time": "2022/08/18 09:29:37",
  "level": "error",
  "pid": "844935",
  "tid": "844935",
  "cid": "44934601",
  "message": "upstream timed out (110: Operation timed out), while connecting to upstream",
  "client": "10.125.172.251",
  "server": "",
  "request": "POST /download HTTP/1.1",
  "upstream": "http://10.117.246.15:84/download",
  "host": "mpm-youtube-downloader-38.name.tldn:84"
}

Protobuf decoder

For correct decoding, the protocol scheme and message name are required. They must be specified in decoder_params.

Params

• proto_file - protocol scheme, can be specified as both the path to the file and the contents of the file.
• proto_message - message name in the specified proto_file.
• proto_import_paths - optional list of paths within which the search will occur (including imports in proto_file). If present and not empty, then all file paths to find are assumed to be relative to one of these paths. Otherwise, all file paths to find are assumed to be relative to the current working directory.

If proto_file contains only system imports, then there is no need to add these files to one of the directories specified in proto_import_paths. Otherwise, all imports specified in the proto_file must be added to one of the directories specified in proto_import_paths respecting the file system tree.

List of system imports:

• google/protobuf/any.proto
• google/protobuf/api.proto
• google/protobuf/compiler/plugin.proto
• google/protobuf/descriptor.proto
• google/protobuf/duration.proto
• google/protobuf/empty.proto
• google/protobuf/field_mask.proto
• google/protobuf/source_context.proto
• google/protobuf/struct.proto
• google/protobuf/timestamp.proto
• google/protobuf/type.proto
• google/protobuf/wrappers.proto

Examples

Decoder with proto-file path:

pipelines:
  example:
    settings:
      decoder: protobuf
      decoder_params:
        proto_file: 'path/to/proto/example.proto'
        proto_message: MyMessage

Decoder with proto-file content:

pipelines:
  example:
    settings:
      decoder: protobuf
      decoder_params:
        proto_file: |
          syntax = "proto3";

          package example;
          option go_package = "example.v1";

          message Data {
            string string_data = 1;
            int32 int_data = 2;
          }

          message MyMessage {
            message InternalData {
              repeated string my_strings = 1;
              bool is_valid = 2;
            }

            Data data = 1;
            InternalData internal_data = 2;
            uint64 version = 3;
          }
        proto_message: MyMessage

Decoder with proto_import_paths:

pipelines:
  example:
    settings:
      decoder: protobuf
      decoder_params:
        proto_file: 'example.proto'
        proto_message: MyMessage
        proto_import_paths:
          - path/to/proto_dir1
          - path/to/proto_dir2

Syslog-RFC3164 decoder

The resulting event may contain any of the following fields:

• priority string
• facility string
• severity string
• timestamp string (Stamp format)
• hostname string
• app_name string
• process_id string
• message string

Params

• syslog_facility_format - facility format, must be one of number|string (number by default).
• syslog_severity_format - severity format, must be one of number|string (number by default).

Examples

Default decoder:

pipelines:
  example:
    settings:
      decoder: 'syslog_rfc3164'

From:

<34>Oct 5 22:14:15 mymachine.example.com myproc[10]: 'myproc' failed on /dev/pts/8

To:

{
  "priority": "34",
  "facility": "4",
  "severity": "2",
  "timestamp": "Oct  5 22:14:15",
  "hostname": "mymachine.example.com",
  "app_name": "myproc",
  "process_id": "10",
  "message": "'myproc' failed on /dev/pts/8"
}

---

Decoder with syslog_*_format params:

pipelines:
  example:
    settings:
      decoder: 'syslog_rfc3164'
      decoder_params:
        syslog_facility_format: 'string'
        syslog_severity_format: 'string'

From:

<34>Oct 11 22:14:15 mymachine.example.com myproc: 'myproc' failed on /dev/pts/8

To:

{
  "priority": "34",
  "facility": "AUTH",
  "severity": "CRIT",
  "timestamp": "Oct 11 22:14:15",
  "hostname": "mymachine.example.com",
  "app_name": "myproc",
  "message": "'myproc' failed on /dev/pts/8"
}

Syslog-RFC5424 decoder

The resulting event may contain any of the following fields:

• priority string
• facility string
• severity string
• proto_version string
• timestamp string (RFC3339/RFC3339Nano format)
• hostname string
• app_name string
• process_id string
• message_id string
• message string
• SD_1 object
• ...
• SD_N object

Params

• syslog_facility_format - facility format, must be one of number|string (number by default).
• syslog_severity_format - severity format, must be one of number|string (number by default).

Examples

Default decoder:

pipelines:
  example:
    settings:
      decoder: 'syslog_rfc5424'

From:

<165>1 2003-10-11T22:14:15.003Z mymachine.example.com myproc 10 ID47 [exampleSDID@32473 iut="3" eventSource="Application" eventID="1011"] An application event log

To:

{
  "priority": "165",
  "facility": "20",
  "severity": "5",
  "proto_version": "1",
  "timestamp": "2003-10-11T22:14:15.003Z",
  "hostname": "mymachine.example.com",
  "app_name": "myproc",
  "process_id": "10",
  "message_id": "ID47",
  "message": "An application event log",
  "exampleSDID@32473": {
    "iut": "3",
    "eventSource": "Application",
    "eventID": "1011"
  }
}

---

Decoder with syslog_*_format params:

pipelines:
  example:
    settings:
      decoder: 'syslog_rfc5424'
      decoder_params:
        syslog_facility_format: 'string'
        syslog_severity_format: 'string'

From:

<165>1 2003-10-11T22:14:15.003Z mymachine.example.com myproc - ID47 [exampleSDID@32473 iut="3" eventSource="Application" eventID="1011"]

To:

{
  "priority": "165",
  "facility": "LOCAL4",
  "severity": "NOTICE",
  "proto_version": "1",
  "timestamp": "2003-10-11T22:14:15.003Z",
  "hostname": "mymachine.example.com",
  "app_name": "myproc",
  "message_id": "ID47",
  "exampleSDID@32473": {
    "iut": "3",
    "eventSource": "Application",
    "eventID": "1011"
  }
}

CSV decoder

Params

• columns - []string, key names in the resulting event (empty by default).
• prefix - string, if columns is empty, key names are formed as follows: {prefix}{i} where {i} is position of field in a row ("" by default)
• delimiter - 1 byte symbol (, by default).
• invalid_line_mode - string, defines the behavior when columns number is not equal to the fields number ​​in a row, must be one of default|continue|fatal (default by default)
  • default - returns error
  • continue - if column number is greater than fields number - skips fields, otherwise fills in missing keys with {prefix}{i}
  • fatal - falls with non-zero exit code

Examples

Default decoder:

pipelines:
  example:
    settings:
      decoder: 'csv'

From:

error,error occurred,2023-10-30T13:35:33.638720813Z,stderr

To:

{
  "0": "error",
  "1": "error occurred",
  "2": "2023-10-30T13:35:33.638720813Z",
  "3": "stderr"
}

---

Decoder with columns and invalid_line_mode param:

pipelines:
  example:
    settings:
      decoder: 'csv'
      decoder_params:
        columns: ['level', 'message', 'ts', 'stream']
        invalid_line_mode: continue

From:

error,error occurred,2023-10-30T13:35:33.638720813Z,stderr,additional field

To:

{
  "level": "error",
  "message": "error occurred",
  "ts": "2023-10-30T13:35:33.638720813Z",
  "stream": "stderr",
  "4": "additional field"
}

---

Decoder with prefix and delimiter params:

pipelines:
  example:
    settings:
      decoder: 'csv'
      decoder_params:
        prefix: 'csv_'
        delimiter: " "

From:

error "error occurred" 2023-10-30T13:35:33.638720813Z stderr

To:

{
  "csv_0": "error",
  "csv_1": "error occurred",
  "csv_2": "2023-10-30T13:35:33.638720813Z",
  "csv_3": "stderr"
}