multiprocess: Add echoipc RPC method and test

Add simple interfaces::Echo IPC interface with one method that just takes and
returns a string, to test multiprocess framework and provide an example of how
it can be used to spawn and call between processes.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/ipc/capnp/init.capnp b/src/ipc/capnp/init.capnp
index be6eecb4b9..e6d358c665 100644
--- a/src/ipc/capnp/init.capnp
+++ b/src/ipc/capnp/init.capnp
@@ -8,9 +8,13 @@ using Cxx = import "/capnp/c++.capnp";
 $Cxx.namespace("ipc::capnp::messages");
 
 using Proxy = import "/mp/proxy.capnp";
+$Proxy.include("interfaces/echo.h");
 $Proxy.include("interfaces/init.h");
 $Proxy.includeTypes("ipc/capnp/init-types.h");
 
+using Echo = import "echo.capnp";
+
 interface Init $Proxy.wrap("interfaces::Init") {
     construct @0 (threadMap: Proxy.ThreadMap) -> (threadMap :Proxy.ThreadMap);
+    makeEcho @1 (context :Proxy.Context) -> (result :Echo.Echo);
 }