Envoy Thrift-To-Metadata Filter

• This filter should be configured with the type URL type.googleapis.com/envoy.extensions.filters.http.thrift_to_metadata.v3.ThriftToMetadata.

• v3 API reference

The thrift-to-metadata filter serves for thrift over HTTP traffic, expecting serialized thrift request and response messages in the HTTP payload. This filter is configured with rules that will be matched against Apache thrift compatible requests and responses in HTTP payload. The filter will parse the thrift messages, extract thrift metadata or thrift payload, and add them to dynamic filter metadata based on the configuration of the rule.

The filter metadata can then be used for load balancing decisions, consumed from logs, etc.

A typical use case for this filter is to dynamically match a specified thrift method of requests with rate limit. For this, thrift method name is attached to the request as dynamic filter metadata which would then be used to match a rate limit action on filter metadata.

Example

A sample filter configuration to route traffic to endpoints based on the presence or absence of a version attribute could be:

thrift-to-metadata-filter.yaml

          http_filters:
          - name: envoy.filters.http.thrift_to_metadata
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.http.thrift_to_metadata.v3.ThriftToMetadata
              request_rules:
              - field: PROTOCOL
                on_present:
                  metadata_namespace: envoy.lb
                  key: protocol
                on_missing:
                  metadata_namespace: envoy.lb
                  key: protocol
                  value: "unknown"
              - field: TRANSPORT
                on_present:
                  metadata_namespace: envoy.lb
                  key: transport
                on_missing:
                  metadata_namespace: envoy.lb
                  key: transport
                  value: "unknown"
              response_rules:
              - field: MESSAGE_TYPE
                on_present:
                  metadata_namespace: envoy.filters.http.thrift_to_metadata
                  key: response_message_type
                on_missing:
                  metadata_namespace: envoy.filters.http.thrift_to_metadata
                  key: response_message_type
                  value: "exception"
              - field: REPLY_TYPE

Statistics

The thrift to metadata filter outputs statistics in the http.<stat_prefix>.thrift_to_metadata. namespace. The stat prefix comes from the owning HTTP connection manager.

Name	Type	Description
rq_success	Counter	Total requests that succeed to parse the thrift message.
rq_mismatched_content_type	Counter	Total requests that mismatch the content type
rq_no_body	Counter	Total requests without http body
rq_invalid_thrift_body	Counter	Total requests with invalid thrift message
resp_success	Counter	Total responses that succeed to parse the thrift message.
resp_mismatched_content_type	Counter	Total responses that mismatch the content type
resp_no_body	Counter	Total responses without http body
resp_invalid_thrift_body	Counter	Total responses with invalid thrift message