How to enable structured JSON logging
This document describes how to configure structured logging for Envoy via Contour.
How the feature works
Contour allows you to choose from a set of JSON fields that will be expanded into Envoy templates and sent to Envoy. There is a default set of fields if you enable JSON logging, and you may customize which fields you log.
The list of available fields are discoverable in the following objects:
- JSONFields are fields that have built in mappings to commonly used envoy operators.
- envoySimpleOperators are the names of simple envoy operators that don’t require arguments, they are case-insensitive when configured.
- envoyComplexOperators are the names of complex envoy operators that require arguments.
The default list of fields is available at DefaultFields.
Enabling the feature
To enable the feature you have two options:
--accesslog-format=jsonto your Contour startup line.
accesslog-format: jsonto your configuration file.
Without any further customization, the default fields will be used.
Customizing logged fields
To customize the logged fields, add a
json-fields list of strings to your
config file. If the
json-fields key is not specified, the
will be configured.
envoyComplexOperators or to use alternative field names, specify strings as
key/value pairs like
Unknown field names in non key/value fields will result in validation errors, as
will unknown Envoy operators in key/value fields. Note that the
FILTER_STATE Envoy logging operators are not supported
at this time due to the complexity of their validation.
See the example config file to see this used in context.
Sample configuration file
Here is a sample config:
accesslog-format: json json-fields: - "@timestamp" - "authority" - "bytes_received" - "bytes_sent" - "customer_id=%REQ(X-CUSTOMER-ID)%" - "downstream_local_address" - "downstream_remote_address" - "duration" - "method" - "path" - "protocol" - "request_id" - "requested_server_name" - "response_code" - "response_flags" - "uber_trace_id" - "upstream_cluster" - "upstream_host" - "upstream_local_address" - "upstream_service_time" - "user_agent" - "x_forwarded_for"