Logging tweaks to use events, in prep for new CLI

src/dds.main.cpp

@@ -8,12 +8,15 @@
 
 #include <boost/leaf/handle_exception.hpp>
 #include <fmt/ostream.h>
+#include <neo/event.hpp>
 
 #include <filesystem>
 #include <iostream>
 
 int main_fn(std::string_view program_name, const std::vector<std::string>& argv) {
     dds::log::init_logger();
+    auto log_subscr = neo::subscribe(&dds::log::ev_log::print);
+
     dds::install_signal_handlers();
 
     dds::cli::options       opts;

src/dds/util/http/pool.cpp

@@ -97,7 +97,7 @@ struct http_client_impl {
             .parse_tail = {},
         };
 
-        dds_log(trace,
+        dds_log(debug,
                 " --> HTTP {} {}://{}:{}{}",
                 params.method,
                 origin.protocol,
@@ -154,7 +154,7 @@ struct http_client_impl {
             disconnect = true;
         }
         _peer_disconnected = disconnect;
-        dds_log(trace, " <-- HTTP {} {}", r.status, r.status_message);
+        dds_log(debug, " <-- HTTP {} {}", r.status, r.status_message);
         return r;
     }
 };
@@ -229,10 +229,16 @@ http_client http_pool::client_for_origin(const network_origin& origin) {
     ret._pool = _impl;
     if (iter == _impl->_clients.end()) {
         // Nothing for this origin yet
+        dds_log(debug, "Opening new connection to {}://{}:{}", origin.protocol, origin.hostname, origin.port);
         auto ptr = std::make_shared<detail::http_client_impl>(origin);
         ptr->connect();
         ret._impl = ptr;
     } else {
+        dds_log(debug,
+                "Reusing existing connection to {}://{}:{}",
+                origin.protocol,
+                origin.hostname,
+                origin.port);
         ret._impl = iter->second;
         _impl->_clients.erase(iter);
     }

src/dds/util/log.cpp

@@ -1,6 +1,7 @@
 #include "./log.hpp"
 
 #include <neo/assert.hpp>
+#include <neo/event.hpp>
 
 #include <spdlog/spdlog.h>
 
@@ -23,6 +24,8 @@ void dds::log::init_logger() noexcept {
     spdlog::set_pattern("[%^%-5l%$] %v");
 }
 
+void dds::log::ev_log::print() const noexcept { log_print(level, message); }
+
 void dds::log::log_print(dds::log::level l, std::string_view msg) noexcept {
     static auto logger_inst = [] {
         auto logger = spdlog::default_logger_raw();
@@ -51,5 +54,18 @@ void dds::log::log_print(dds::log::level l, std::string_view msg) noexcept {
         neo_assert_always(invariant, false, "Invalid log level", msg, int(l));
     }();
 
-    logger_inst->log(lvl, "{}", msg);
+    logger_inst->log(lvl, msg);
+}
+
+void dds::log::log_emit(dds::log::ev_log ev) noexcept {
+    if (!neo::get_event_subscriber<ev_log>()) {
+        thread_local bool did_warn = false;
+        if (!did_warn) {
+            log_print(level::warn,
+                      "The calling thread issued a log message, but there is no subscriber "
+                      "listening for it. The log message will be dropped. This is a bug!");
+            did_warn = true;
+        }
+    }
+    neo::emit(ev);
 }

src/dds/util/log.hpp

@@ -18,7 +18,15 @@ enum class level : int {
 
 inline level current_log_level = level::info;
 
+struct ev_log {
+    log::level       level;
+    std::string_view message;
+
+    void print() const noexcept;
+};
+
 void log_print(level l, std::string_view s) noexcept;
+void log_emit(ev_log) noexcept;
 
 void init_logger() noexcept;
 
@@ -33,7 +41,7 @@ template <formattable... Args>
 void log(level l, std::string_view s, const Args&... args) noexcept {
     if (int(l) >= int(current_log_level)) {
         auto message = fmt::format(s, args...);
-        log_print(l, message);
+        log_emit(ev_log{l, message});
     }
 }
 

src/dds/util/parallel.hpp

@@ -1,5 +1,9 @@
 #pragma once
 
+#include <dds/util/log.hpp>
+
+#include <neo/event.hpp>
+
 #include <algorithm>
 #include <iterator>
 #include <mutex>
@@ -23,6 +27,8 @@ bool parallel_run(Range&& rng, int n_jobs, Func&& fn) {
     std::vector<std::exception_ptr> exceptions;
 
     auto run_one = [&]() mutable {
+        auto log_subscr = neo::subscribe(&log::ev_log::print);
+
         while (true) {
             std::unique_lock lk{mut};
             if (!exceptions.empty()) {