handle fallback console logging for grpc log failures

Author: lia-viam

src/viam/sdk/log/logging.cpp

@@ -12,6 +12,7 @@
 
 #include <viam/sdk/common/instance.hpp>
 #include <viam/sdk/common/private/instance.hpp>
+#include <viam/sdk/log/private/log_backend.hpp>
 
 namespace viam {
 namespace sdk {
@@ -136,7 +137,18 @@ void LogManager::init_logging() {
 
 void LogManager::disable_console_logging() {
     VIAM_LOG(debug) << "Disabling console logging";
-    boost::log::core::get()->remove_sink(console_sink_);
+
+    // Set a filter which ignores all console logs unless they contain a console force flag which is
+    // set to true.
+    console_sink_->set_filter(
+        [filter = Filter{this}](const boost::log::attribute_value_set& attrs) {
+            auto force = attrs[impl::attr_console_force_type{}];
+            if (force && *force) {
+                return filter(attrs);
+            }
+
+            return false;
+        });
 }
 
 namespace log_detail {

src/viam/sdk/log/private/log_backend.hpp

@@ -25,6 +25,11 @@ struct LogBackend : boost::log::sinks::basic_sink_backend<boost::log::sinks::syn
     RobotClient* parent;
 };
 
+// TBD if we want to expose this to users, but for now it is an implementation detail.
+// Disabling console logging is implemented by changing the filter on the console sink to reject all
+// messages unless they have a "force" flag set to true.
+BOOST_LOG_ATTRIBUTE_KEYWORD_TYPE(attr_console_force, "force", bool);
+
 }  // namespace impl
 }  // namespace sdk
 }  // namespace viam

src/viam/sdk/robot/client.cpp

@@ -101,7 +101,15 @@ void RobotClient::connect_logging() {
     auto& sink = impl_->log_sink;
     if (!sink) {
         sink = sdk::impl::LogBackend::create(this);
-        sink->set_filter(LogManager::Filter{&LogManager::get()});
+        sink->set_filter([filter = LogManager::Filter{&LogManager::get()}](
+                             const boost::log::attribute_value_set& attrs) {
+            auto force = attrs[sdk::impl::attr_console_force_type{}];
+            if (force && *force) {
+                return false;
+            }
+
+            return filter(attrs);
+        });
 
         LogManager::get().disable_console_logging();
         boost::log::core::get()->add_sink(sink);
@@ -270,7 +278,13 @@ void RobotClient::log(const std::string& name,
     robot::v1::LogResponse resp;
     ClientContext ctx;
     const auto response = impl_->stub_->Log(ctx, req, &resp);
-    (void)response;
+    if (is_error_response(response)) {
+        // Manually override to force this to get logged to console so we don't set off an infinite
+        // loop
+        VIAM_LOG(error) << boost::log::add_value(sdk::impl::attr_console_force_type{}, true)
+                        << "Error sending log message over grpc: " << response.error_message()
+                        << response.error_details();
+    }
 }
 
 std::shared_ptr<RobotClient> RobotClient::with_channel(std::shared_ptr<ViamChannel> channel,