log: initialize logging earlier

It turns out to be possible to initialize logging earlier by
grabbing the log from a global ngx_cycle structure.

This makes us start logging earlier, yet loses the
"No threading detected ..." messages both from stderr and
in error.log when nginx initially starts.

With this change, these messages will now be logged as we start
logging earlier:

"
flush
.
"

These originate from SystemCachePath::CacheKey which appends
newlines to the key, and the resulting cache key ends up being
logged. We might want to change that, because the resulting
lines in error.log look weird and might raise questions.

Fixes https://github.com/pagespeed/ngx_pagespeed/issues/895

src/ngx_pagespeed.cc

@@ -983,6 +983,7 @@ void* ps_create_main_conf(ngx_conf_t* cf) {
       "" /* hostname, not used */,
       -1 /* port, not used */);
   active_driver_factory = cfg_m->driver_factory;
+  active_driver_factory->LoggingInit(ngx_cycle->log, false);
   cfg_m->driver_factory->Init();
   ps_set_conf_cleanup_handler(cf, ps_cleanup_main_conf, cfg_m);
   return cfg_m;
@@ -3044,7 +3045,7 @@ ngx_int_t ps_init_module(ngx_cycle_t* cycle) {
       return NGX_ERROR;
     }
 
-    cfg_m->driver_factory->LoggingInit(cycle->log);
+    cfg_m->driver_factory->LoggingInit(cycle->log, true);
     cfg_m->driver_factory->RootInit();
   } else {
     delete cfg_m->driver_factory;
@@ -3076,7 +3077,7 @@ ngx_int_t ps_init_child_process(ngx_cycle_t* cycle) {
 
   // ChildInit() will initialise all ServerContexts, which we need to
   // create ProxyFetchFactories below
-  cfg_m->driver_factory->LoggingInit(cycle->log);
+  cfg_m->driver_factory->LoggingInit(cycle->log, true);
   cfg_m->driver_factory->ChildInit();
 
   ngx_http_core_main_conf_t* cmcf = static_cast<ngx_http_core_main_conf_t*>(

src/ngx_rewrite_driver_factory.cc

@@ -208,10 +208,11 @@ void NgxRewriteDriverFactory::StartThreads() {
   threads_started_ = true;
 }
 
-void NgxRewriteDriverFactory::LoggingInit(ngx_log_t* log) {
+void NgxRewriteDriverFactory::LoggingInit(
+    ngx_log_t* log, bool may_install_crash_handler) {
   log_ = log;
   net_instaweb::log_message_handler::Install(log);
-  if (install_crash_handler()) {
+  if (may_install_crash_handler && install_crash_handler()) {
     NgxMessageHandler::InstallCrashHandler(log);
   }
   ngx_message_handler_->set_log(log);

src/ngx_rewrite_driver_factory.h

@@ -115,7 +115,7 @@ class NgxRewriteDriverFactory : public SystemRewriteDriverFactory {
     return process_script_variables_;
   }
 
-  void LoggingInit(ngx_log_t* log);
+  void LoggingInit(ngx_log_t* log, bool may_install_crash_handler);
 
   virtual void ShutDownMessageHandlers();