Fix ZENOH_ROUTER_CHECK_ATTEMPTS which was not respected (#427)

* Fix check of connection to a router * README: update ZENOH_ROUTER_CHECK_ATTEMPTS following default value change in #308 (cherry picked from commit 6f910bf)
ros2 · Jan 17, 2025 · 589993a · 589993a
1 parent ceb6d28
commit 589993a
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diff --git a/README.md b/README.md
@@ -83,11 +83,15 @@ The `ZENOH_ROUTER_CHECK_ATTEMPTS` environment variable can be used to configure
 The behavior is explained in the table below.
 
 
-| ZENOH_ROUTER_CHECK_ATTEMPTS |                                                 Session behavior                                                 |
-|:---------------------------:|:----------------------------------------------------------------------------------------------------------------:|
-|            unset or 0           |                                                             Indefinitely waits for connection to a Zenoh router. |
-|             < 0            |                                                                                        Skips Zenoh router check. |
+| ZENOH_ROUTER_CHECK_ATTEMPTS |                                                 Session behavior                                                   |
+|:---------------------------:|:------------------------------------------------------------------------------------------------------------------:|
+|               0             |                                                             Indefinitely waits for connection to a Zenoh router.   |
+|             < 0             |                                                                                        Skips Zenoh router check.   |
 |             > 0             | Attempts to connect to a Zenoh router in `ZENOH_ROUTER_CHECK_ATTEMPTS` attempts with 1 second wait between checks. |
+|            unset            |                                                                    Equivalent to `1`: the check is made only once. |
+
+If after the configured number of attempts the Node is still not connected to a `Zenoh router`, the initialisation goes on anyway.  
+If a `Zenoh router` is started after initialization phase, the Node will automatically connect to it, and autoconnect to other Nodes if gossip scouting is enabled (true with default configuratiuon).
 
 ### Session and Router configs
 `rmw_zenoh` relies on separate configurations files to configure the `Zenoh router` and `Zenoh session` respectively.

diff --git a/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp b/rmw_zenoh_cpp/src/detail/rmw_context_impl_s.cpp
@@ -100,8 +100,8 @@ class rmw_context_impl_s::Data final : public std::enable_shared_from_this<Data>
       constexpr int64_t ticks_between_print(std::chrono::milliseconds(1000) / sleep_time);
       do {
         zenoh::ZResult result;
-        this->session_->get_routers_z_id(&result);
-        if (result == Z_OK) {
+        const auto zids = this->session_->get_routers_z_id(&result);
+        if (result == Z_OK && !zids.empty()) {
           break;
         }
         if ((connection_attempts % ticks_between_print) == 0) {