afb-stub-ws: Add reconnection of ws-clients on need

This implementation detects deconnections and try to reconnect
lazily on need.

Bug-AGL: SPEC-1668

Change-Id: Ib2a20a4578f2da80afe1564c42de96c4aa250e64
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

diff --git a/src/afb-api-ws.c b/src/afb-api-ws.c
index 6d8506c..8069da2 100644 (file)
--- a/src/afb-api-ws.c
+++ b/src/afb-api-ws.c
@@ -50,6 +50,12 @@ struct api_ws_server
 /***       C L I E N T                                                      ***/
 /******************************************************************************/
 
+static struct fdev *reopen_client(void *closure)
+{
+       const char *uri = closure;
+       return afb_socket_open_fdev(uri, 0);
+}
+
 int afb_api_ws_add_client(const char *uri, struct afb_apiset *declare_set, struct afb_apiset *call_set, int strong)
 {
        struct afb_stub_ws *stubws;
@@ -73,8 +79,16 @@ int afb_api_ws_add_client(const char *uri, struct afb_apiset *declare_set, struc
                        ERROR("can't setup client ws service to %s", uri);
                        fdev_unref(fdev);
                } else {
-                       if (afb_stub_ws_client_add(stubws, declare_set) >= 0)
+                       if (afb_stub_ws_client_add(stubws, declare_set) >= 0) {
+#if 1
+                               /* it is asserted here that uri is never released */
+                               afb_stub_ws_client_robustify(stubws, reopen_client, (void*)uri, NULL);
+#else
+                               /* it is asserted here that uri is released, so use a copy */
+                               afb_stub_ws_client_robustify(stubws, reopen_client, strdup(uri), free);
+#endif
                                return 0;
+                       }
                        ERROR("can't add the client to the apiset for service %s", uri);
                        afb_stub_ws_unref(stubws);
                }

diff --git a/src/afb-stub-ws.c b/src/afb-stub-ws.c
index 19b9b61..a41a9b0 100644 (file)
--- a/src/afb-stub-ws.c
+++ b/src/afb-stub-ws.c
@@ -128,6 +128,13 @@ struct afb_stub_ws
                struct {
                        /* event replica  */
                        struct client_event *events;
+
+                       /* robustify */
+                       struct {
+                               struct fdev *(*reopen)(void*);
+                               void *closure;
+                               void (*release)(void*);
+                       } robust;
                };
        };
 
@@ -141,6 +148,8 @@ struct afb_stub_ws
        char apiname[1];
 };
 
+static struct afb_proto_ws *afb_stub_ws_create_proto(struct afb_stub_ws *stubws, struct fdev *fdev, uint8_t server);
+
 /******************* ws request part for server *****************/
 
 /* decrement the reference count of the request and free/release it on falling to null */
@@ -229,19 +238,35 @@ static struct client_event *client_event_search(struct afb_stub_ws *stubws, uint
        return ev;
 }
 
+static struct afb_proto_ws *client_get_proto(struct afb_stub_ws *stubws)
+{
+       struct fdev *fdev;
+       struct afb_proto_ws *proto;
+
+       proto = stubws->proto;
+       if (proto == NULL && stubws->robust.reopen) {
+               fdev = stubws->robust.reopen(stubws->robust.closure);
+               if (fdev != NULL)
+                       proto = afb_stub_ws_create_proto(stubws, fdev, 0);
+       }
+       return proto;
+}
+
 /* on call, propagate it to the ws service */
 static void client_api_call_cb(void * closure, struct afb_xreq *xreq)
 {
        int rc;
        struct afb_stub_ws *stubws = closure;
+       struct afb_proto_ws *proto;
 
-       if (stubws->proto == NULL) {
+       proto = client_get_proto(stubws);
+       if (proto == NULL) {
                afb_xreq_reply(xreq, NULL, "disconnected", "server hung up");
                return;
        }
 
        rc = afb_proto_ws_client_call(
-                       stubws->proto,
+                       proto,
                        xreq->request.called_verb,
                        afb_xreq_json(xreq),
                        afb_session_uuid(xreq->context.session),
@@ -264,12 +289,14 @@ static void client_on_description_cb(void *closure, struct json_object *data)
 static void client_send_describe_cb(int signum, void *closure, struct jobloop *jobloop)
 {
        struct client_describe *desc = closure;
+       struct afb_proto_ws *proto;
 
-       if (signum || desc->stubws->proto == NULL)
+       proto = client_get_proto(desc->stubws);
+       if (signum || proto == NULL)
                jobs_leave(jobloop);
        else {
                desc->jobloop = jobloop;
-               afb_proto_ws_client_describe(desc->stubws->proto, client_on_description_cb, desc);
+               afb_proto_ws_client_describe(proto, client_on_description_cb, desc);
        }
 }
 
@@ -685,6 +712,12 @@ void afb_stub_ws_unref(struct afb_stub_ws *stubws)
 {
        if (stubws && !__atomic_sub_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED)) {
 
+               if (stubws->is_client) {
+                       stubws->robust.reopen = NULL;
+                       if (stubws->robust.release)
+                               stubws->robust.release(stubws->robust.closure);
+               }
+
                disconnect(stubws);
                afb_apiset_unref(stubws->apiset);
                free(stubws);
@@ -713,7 +746,7 @@ struct afb_api_item afb_stub_ws_client_api(struct afb_stub_ws *stubws)
        assert(stubws->is_client); /* check client */
        api.closure = stubws;
        api.itf = &client_api_itf;
-       api.group = NULL;
+       api.group = stubws; /* serialize for reconnections */
        return api;
 }
 
@@ -721,3 +754,15 @@ int afb_stub_ws_client_add(struct afb_stub_ws *stubws, struct afb_apiset *apiset
 {
        return afb_apiset_add(apiset, stubws->apiname, afb_stub_ws_client_api(stubws));
 }
+
+void afb_stub_ws_client_robustify(struct afb_stub_ws *stubws, struct fdev *(*reopen)(void*), void *closure, void (*release)(void*))
+{
+       assert(stubws->is_client); /* check client */
+
+       if (stubws->robust.release)
+               stubws->robust.release(stubws->robust.closure);
+
+       stubws->robust.reopen = reopen;
+       stubws->robust.closure = closure;
+       stubws->robust.release = release;
+}

diff --git a/src/afb-stub-ws.h b/src/afb-stub-ws.h
index f236937..c087726 100644 (file)
--- a/src/afb-stub-ws.h
+++ b/src/afb-stub-ws.h
@@ -39,3 +39,5 @@ extern struct afb_api_item afb_stub_ws_client_api(struct afb_stub_ws *stubws);
 
 extern int afb_stub_ws_client_add(struct afb_stub_ws *stubws, struct afb_apiset *apiset);
 
+extern void afb_stub_ws_client_robustify(struct afb_stub_ws *stubws, struct fdev *(*reopen)(void*), void *closure, void (*release)(void*));
+