Envoy Database Filters: Access Logging, MongoDB, DynamoDB, and Redis Support

Envoy provides extensible access logging for HTTP connection managers and TCP proxies, supporting multiple logs per manager, asynchronous I/O flushing, customizable formats, and filterable logs.

The MongoDB sniffing filter adds a BSON parser, detailed query/operation statistics, per‑callsite metrics, and fault injection, and is used at Lyft to gather platform‑agnostic data across applications.

The DynamoDB HTTP‑level filter parses API requests/responses, collects per‑operation/table/partition statistics, tracks 4xx failure types, and aggregates batch operation failures, offering platform‑agnostic insight for applications using the AWS SDK.

Envoy can act as a Redis proxy, partitioning commands across cluster instances, providing a Redis protocol codec, hash‑based partitioning, detailed command statistics, and health checks. Planned enhancements include additional timing stats, circuit breaking, request collapsing, replication, retries, tracing, and hash tags.

Supported Redis commands are listed by group (generic, hash, list, set, sorted set, string, scripting). Errors from Redis are passed through as normal responses; Envoy can also generate its own errors. A sample MGET error response is shown:

$ redis-cli MGET a b c d e
1) "alpha"
2) "bravo"
3) (error) upstream failure
4) (error) upstream failure
5) "echo"

Configuration references for each filter (access log, MongoDB, DynamoDB, Redis) are provided, including required cluster definitions and health‑check settings.