app: RPC to wait for app subsystem initialization.

Change-Id: I66a9f9c1a92c8b9185a0c4c882e61b028e1da261
Signed-off-by: Seth Howell <seth.howell@intel.com>
Reviewed-on: https://review.gerrithub.io/432491
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>

doc/jsonrpc.md

@@ -164,6 +164,39 @@ Example response:
 }
 ~~~
 
+## wait_subsystem_init {#rpc_wait_subsystem_init}
+
+Do not return until all subsystems have been initialized and the RPC system state is running.
+If the application is already running, this call will return immediately. This RPC can be called at any time.
+
+### Parameters
+
+This method has no parameters.
+
+### Response
+
+Returns True when subsystems have been initialized.
+
+### Example
+
+Example request:
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "method": "wait_subsystem_init"
+}
+~~~
+
+Example response:
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## get_rpc_methods {#rpc_get_rpc_methods}
 
 Get an array of supported RPC methods.

lib/event/app.c

@@ -1007,3 +1007,57 @@ spdk_rpc_start_subsystem_init(struct spdk_jsonrpc_request *request,
 	spdk_subsystem_init(cb_event);
 }
 SPDK_RPC_REGISTER("start_subsystem_init", spdk_rpc_start_subsystem_init, SPDK_RPC_STARTUP)
+
+struct subsystem_init_poller_ctx {
+	struct spdk_poller *init_poller;
+	struct spdk_jsonrpc_request *request;
+};
+
+static int
+spdk_rpc_subsystem_init_poller_ctx(void *ctx)
+{
+	struct spdk_json_write_ctx *w;
+	struct subsystem_init_poller_ctx *poller_ctx = ctx;
+
+	if (spdk_rpc_get_state() == SPDK_RPC_RUNTIME) {
+		w = spdk_jsonrpc_begin_result(poller_ctx->request);
+		if (w == NULL) {
+			SPDK_ERRLOG("Unable to allocate memory for RPC response\n");
+		} else {
+			spdk_json_write_bool(w, true);
+		}
+		spdk_jsonrpc_end_result(poller_ctx->request, w);
+		spdk_poller_unregister(&poller_ctx->init_poller);
+		free(poller_ctx);
+	}
+
+	return 1;
+}
+
+static void
+spdk_rpc_wait_subsystem_init(struct spdk_jsonrpc_request *request,
+			     const struct spdk_json_val *params)
+{
+	struct spdk_json_write_ctx *w;
+	struct subsystem_init_poller_ctx *ctx;
+
+	if (spdk_rpc_get_state() == SPDK_RPC_RUNTIME) {
+		w = spdk_jsonrpc_begin_result(request);
+		if (w == NULL) {
+			return;
+		}
+		spdk_json_write_bool(w, true);
+		spdk_jsonrpc_end_result(request, w);
+	} else {
+		ctx = malloc(sizeof(struct subsystem_init_poller_ctx));
+		if (ctx == NULL) {
+			spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+							 "Unable to allocate memory for the request context\n");
+			return;
+		}
+		ctx->request = request;
+		ctx->init_poller = spdk_poller_register(spdk_rpc_subsystem_init_poller_ctx, ctx, 0);
+	}
+}
+SPDK_RPC_REGISTER("wait_subsystem_init", spdk_rpc_wait_subsystem_init,
+		  SPDK_RPC_STARTUP | SPDK_RPC_RUNTIME)

scripts/rpc.py

@@ -48,6 +48,13 @@ if __name__ == "__main__":
     p = subparsers.add_parser('start_subsystem_init', help='Start initialization of subsystems')
     p.set_defaults(func=start_subsystem_init)
 
+    @call_cmd
+    def wait_subsystem_init(args):
+        rpc.wait_subsystem_init(args.client)
+
+    p = subparsers.add_parser('wait_subsystem_init', help='Block until subsystems have been initialized')
+    p.set_defaults(func=wait_subsystem_init)
+
     @call_cmd
     def get_rpc_methods(args):
         print_dict(rpc.get_rpc_methods(args.client,

scripts/rpc/__init__.py

@@ -22,6 +22,11 @@ def start_subsystem_init(client):
     return client.call('start_subsystem_init')
 
 
+def wait_subsystem_init(client):
+    """Block until subsystems have been initialized"""
+    return client.call('wait_subsystem_init')
+
+
 def get_rpc_methods(client, current=None):
     """Get list of supported RPC methods.
     Args: