Formatter extension for printing various types of metadata (proto)
This extension has the qualified name envoy.formatter.metadata
Note
This extension is functional but has not had substantial production burn time, use only with this caveat.
This extension is intended to be robust against both untrusted downstream and upstream traffic.
Tip
This extension extends and can be used with the following extension category:
This extension must be configured with one of the following type URLs:
Metadata formatter extension implements METADATA command operator that prints all types of metadata. The first parameter taken by METADATA operator defines type of metadata. The following types of metadata are supported (case sensitive):
DYNAMIC
CLUSTER
ROUTE
UPSTREAM_HOST
LISTENER
See here for more information on access log configuration.
- %METADATA(TYPE:NAMESPACE:KEY):Z%
Metadata info, where TYPE is type of metadata (see above for supported types), NAMESPACE is the filter namespace used when setting the metadata, KEY is an optional lookup key in the namespace with the option of specifying nested keys separated by ‘:’, and Z is an optional parameter denoting string truncation up to Z characters long. The data will be logged as a JSON string. For example, for the following ROUTE metadata:
com.test.my_filter: {"test_key": "foo", "test_object": {"inner_key": "bar"}}%METADATA(ROUTE:com.test.my_filter)% will log:
{"test_key": "foo", "test_object": {"inner_key": "bar"}}%METADATA(ROUTE:com.test.my_filter:test_key)% will log:
foo%METADATA(ROUTE:com.test.my_filter:test_object)% will log:
{"inner_key": "bar"}%METADATA(ROUTE:com.test.my_filter:test_object:inner_key)% will log:
bar%METADATA(ROUTE:com.unknown_filter)% will log:
-%METADATA(ROUTE:com.test.my_filter:unknown_key)% will log:
-%METADATA(ROUTE:com.test.my_filter):25% will log (truncation at 25 characters):
{"test_key": "foo", "test
Note
For typed JSON logs, this operator renders a single value with string, numeric, or boolean type when the referenced key is a simple value. If the referenced key is a struct or list value, a JSON struct or list is rendered. Structs and lists may be nested. In any event, the maximum length is ignored.
Note
METADATA(DYNAMIC:NAMESPACE:KEY):Z is equivalent to DYNAMIC_METADATA(NAMESPACE:KEY):Z METADATA(CLUSTER:NAMESPACE:KEY):Z is equivalent to CLUSTER_METADATA(NAMESPACE:KEY):Z METADATA(UPSTREAM_HOST:NAMESPACE:KEY):Z is equivalent to UPSTREAM_METADATA(NAMESPACE:KEY):Z