MeshAccessLog

This guide assumes you have already configured your observability tools to work with Kuma. If you haven’t, see the observability docs.

To learn more about the information in this table, see the matching docs.

Format

Kuma gives you full control over the format of the access logs.

The shape of a single log record is defined by a template string that uses command operators to extract and format data about a TCP connection or an HTTP request.

For example:

%START_TIME% %KUMA_SOURCE_SERVICE% => %KUMA_DESTINATION_SERVICE% %DURATION%

%START_TIME% and %KUMA_SOURCE_SERVICE% are examples of available command operators.

All command operators defined by Envoy are supported, along with additional command operators defined by Kuma:

All additional access log command operators are valid to use with both TCP and HTTP traffic.

Internally, Kuma determines traffic protocol based on the value of kuma.io/protocol tag on the inbound interface of a destination Dataplane.

There are two types of format, plain and json.

Plain accepts a string with command operators and produces a string output.

JSON accepts a list of key-value pairs that produces a valid JSON object.

It is up to the user to decide which format type to use. Some system will automatically parse JSON logs and allow you to filter and query based on available keys.

If a command operator is specific to HTTP traffic, such as %REQ(X?Y):Z% or %RESP(X?Y):Z%, in the case of TCP traffic it will be replaced by a symbol “-” for plain and a null value for json. You can set the format.omitEmptyValues boolean option to change this to "" for plain and omit them entirely for json.

Plain

The default format string for TCP traffic is:

[%START_TIME%] %RESPONSE_FLAGS% %KUMA_MESH% %KUMA_SOURCE_ADDRESS_WITHOUT_PORT%(%KUMA_SOURCE_SERVICE%)->%UPSTREAM_HOST%(%KUMA_DESTINATION_SERVICE%) took %DURATION%ms, sent %BYTES_SENT% bytes, received: %BYTES_RECEIVED% bytes

The default format string for HTTP traffic is:

[%START_TIME%] %KUMA_MESH% "%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%" %RESPONSE_CODE% %RESPONSE_FLAGS% %BYTES_RECEIVED% %BYTES_SENT% %DURATION% %RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)% "%REQ(X-FORWARDED-FOR)%" "%REQ(USER-AGENT)%" "%REQ(X-REQUEST-ID)%" "%REQ(:AUTHORITY)%" "%KUMA_SOURCE_SERVICE%" "%KUMA_DESTINATION_SERVICE%" "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%" "%UPSTREAM_HOST%"

Example configuration:

format:
  type: Plain
  plain: '[%START_TIME%] %BYTES_RECEIVED%'

Example output:

[2016-04-15T20:17:00.310Z] 154

JSON

Example configuration:

format:
  type: Json
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"

Example output:

{
  "start_time": "2016-04-15T20:17:00.310Z",
  "bytes_received": "154"
}

format:
  type: Json
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "response_flags"
      value: "%RESPONSE_FLAGS%"
    - key: "kuma_mesh"
      value: "%KUMA_MESH%"
    - key: "kuma_source_address_without_port"
      value: "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%"
    - key: "kuma_source_service"
      value: "%KUMA_SOURCE_SERVICE%"
    - key: "upstream_host"
      value: "%UPSTREAM_HOST%"
    - key: "kuma_destination_service"
      value: "%KUMA_DESTINATION_SERVICE%"
    - key: "duration_ms"
      value: "%DURATION%"
    - key: "bytes_sent"
      value: "%BYTES_SENT%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"

format:
  type: Json
  json:
    - key: "start_time"
      value: "%START_TIME%"
    - key: "kuma_mesh"
      value: "%KUMA_MESH%"
    - key: 'method'
      value: '"%REQ(:METHOD)%'
    - key: "path"
      value: "%REQ(X-ENVOY-ORIGINAL-PATH?:PATH)%"
    - key: 'protocol'
      value: '%PROTOCOL%'
    - key: "response_code"
      value: "%RESPONSE_CODE%"
    - key: "response_flags"
      value: "%RESPONSE_FLAGS%"
    - key: "bytes_received"
      value: "%BYTES_RECEIVED%"
    - key: "bytes_sent"
      value: "%BYTES_SENT%"
    - key: "duration_ms"
      value: "%DURATION%"
    - key: "upstream_service_time"
      value: "%RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%"
    - key: 'x_forwarded_for'
      value: '"%REQ(X-FORWARDED-FOR)%"'
    - key: 'user_agent'
      value: '"%REQ(USER-AGENT)%"'
    - key: 'request_id'
      value: '"%REQ(X-REQUEST-ID)%"'
    - key: 'authority'
      value: '"%REQ(:AUTHORITY)%"'
    - key: "kuma_source_service"
      value: "%KUMA_SOURCE_SERVICE%"
    - key: "kuma_destination_service"
      value: "%KUMA_DESTINATION_SERVICE%"
    - key: "kuma_source_address_without_port"
      value: "%KUMA_SOURCE_ADDRESS_WITHOUT_PORT%"
    - key: "upstream_host"
      value: "%UPSTREAM_HOST%"

Backends

A backend determines where the logs end up.

TCP

A TCP backend streams logs to a server via TCP protocol. You can configure a TCP backend with an address:

backends:
  - type: Tcp
    tcp:
      address: 127.0.0.1:5000

File

A file backend streams logs to a text file. You can configure a file backend with a path:

backends:
  - type: File
    file:
      path: /dev/stdout

OpenTelemetry

An OpenTelemetry (OTEL) backend sends data to an OpenTelemetry server. You can configure an OpenTelemetry backend with an endpoint, attributes (which contain additional information about the log) and body (can be a string message, including multi-line, or it can be a structured data). Attributes and endpoints can use placeholders described in the format section.

backends:
  - type: OpenTelemetry
    openTelemetry:
      endpoint: otel-collector:4317
      body:
        kvlistValue:
          values:
            - key: "mesh"
              value:
                stringValue: "%KUMA_MESH%"
      attributes:
        - key: "start_time"
          value: "%START_TIME%"

Body

Body is of type any (defined here) and can be one of the following forms:

body:
  stringValue: "%KUMA_MESH%"

body:
  boolValue: true

body:
  intValue: 123

body:
  doubleValue: 1.2

body:
  bytesValue: aGVsbG8=

body:
  arrayValue:
    values:
      - stringValue: "%KUMA_MESH%"

body:
  kvlistValue:
    values:
      - key: "mesh"
        value:
          stringValue: "%KUMA_MESH%"