Collectd 'daemon' module

Per-cpu value list registry with polling -> udp send

- Allows registration of metric values associated with
  collectd id path (plugin/[plugin-inst/]type[/type-instance]).
- Values are broadcast/sent at periodic intervals. (config)
- Config through seastar.conf / app-template.
- Value registration can be revoked safely, either manually or
  through anchor.

Signed-off-by: Calle Wilund <[email protected]>

configure.py

@@ -42,6 +42,7 @@
     'core/posix.cc',
     'core/memory.cc',
     'core/resource.cc',
+    'core/scollectd.cc',
     'util/conversions.cc',
     'net/packet.cc',
     'net/posix-stack.cc',

core/app-template.hh

@@ -8,6 +8,7 @@
 #include <fstream>
 #include <cstdlib>
 #include "core/reactor.hh"
+#include "core/scollectd.hh"
 
 namespace bpo = boost::program_options;
 
@@ -22,6 +23,7 @@ public:
                 ;
         _opts.add(reactor::get_options_description());
         _opts.add(smp::get_options_description());
+        _opts.add(scollectd::get_options_description());
     };
 
     boost::program_options::options_description_easy_init add_options() {
@@ -47,6 +49,7 @@ public:
             return 1;
         }
         smp::configure(configuration);
+        scollectd::configure(configuration);
         _configuration = {std::move(configuration)};
         engine.when_started().then(func).rescue([] (auto get_ex) {
             try {