Module extension 

Command-dispatch extension hook.

The cluster substrate ships the parser, the dispatcher, and the standard data-plane commands (GET / SET / HSET / …). Layered surfaces - notably the RediSearch FT.* commands - plug in via the CommandExtension trait so the substrate does not need to know about them at compile time.

Lifecycle

1. The embedder constructs a crate::embed::ServerBuilder.
2. The embedder (or a helper crate such as dynomite-search) attaches a CommandExtension via crate::embed::ServerBuilder::with_command_extension or crate::embed::ServerBuilder::set_command_extension.
3. The dispatcher consults the extension in the hot path:
   • For commands the parser tags as crate::msg::MsgType::ReqRedisFtCreate / crate::msg::MsgType::ReqRedisFtSearch / crate::msg::MsgType::ReqRedisFtInfo / crate::msg::MsgType::ReqRedisFtList / crate::msg::MsgType::ReqRedisFtDropindex / crate::msg::MsgType::ReqRedisFtRegex / crate::msg::MsgType::ReqRedisFtSugadd / crate::msg::MsgType::ReqRedisFtSugget / crate::msg::MsgType::ReqRedisFtSugdel / crate::msg::MsgType::ReqRedisFtSuglen / crate::msg::MsgType::ReqRedisFtUnknown the dispatcher checks CommandExtension::handles_msg_type and, if true, delegates execution to CommandExtension::try_dispatch.
   • Every HSET request is offered to CommandExtension::try_intercept_hset before the standard fan-out path runs.
4. When no extension is wired the dispatcher behaves exactly as it did before this hook existed: FT.* keywords are forwarded to the local datastore (which typically rejects them with -ERR unknown command).

Implementations are object-safe; the dispatcher holds an std::sync::Arc<dyn CommandExtension> and clones the handle freely across tasks.

Enums

HsetOutcome

Outcome of CommandExtension::try_intercept_hset.

Traits

CommandExtension

Pluggable command-dispatch hook.