build: Introduce the agent-interface as an alternative instrumentation library

The agent-interface is an experimental instrumentation library for
capturing and sharing Spice performance indicators with an external
agent.

    --enable-instrumentation=[recorder/agent/no]
             Enable instrumentation [default=no]

The former configuration option '--enable-recorder' is transformed
into '--enable-instrumentation=recorder'.

Signed-off-by: Kevin Pouget <kpouget@redhat.com>
Acked-by: Frediano Ziglio <fziglio@redhat.com>

common/Makefile.am

@@ -65,6 +65,13 @@ libspice_common_la_SOURCES += \
 	$(NULL)
 endif
 
+if ENABLE_AGENT_INTERFACE
+libspice_common_la_SOURCES += \
+	agent_interface.c		\
+	agent_interface.h		\
+	$(NULL)
+endif
+
 # These 2 files are not build as part of spice-common
 # build system, but modules using spice-common will build
 # them with the appropriate options. We need to let automake

common/meson.build

@@ -41,7 +41,7 @@ spice_common_sources = [
   'recorder.h'
 ]
 
-if get_option('recorder')
+if get_option('instrumentation') == 'recorder'
   spice_common_sources += [
     'recorder/recorder.c',
     'recorder/recorder.h',
@@ -49,6 +49,12 @@ if get_option('recorder')
     'recorder/recorder_ring.h'
   ]
 endif
+if get_option('instrumentation') == 'agent'
+  spice_common_sources += [
+    'agent_interface.c',
+    'agent_interface.h'
+  ]
+endif
 
 spice_common_lib = static_library('spice-common', spice_common_sources,
                                   install : false,

common/recorder.h

@@ -16,7 +16,14 @@
 */
 /* This file include recorder library headers or if disabled provide
  * replacement declarations */
-#ifndef ENABLE_RECORDER
+
+#ifdef ENABLE_RECORDER
+#include <common/recorder/recorder.h>
+
+#elif defined(ENABLE_AGENT_INTERFACE)
+#include <common/agent_interface.h>
+
+#else
 
 #include <stdio.h>
 #include <stdint.h>
@@ -69,9 +76,6 @@ static inline void
 recorder_dump_on_common_signals(unsigned add, unsigned remove)
 {
 }
-
-#else
-#include <common/recorder/recorder.h>
 #endif
 
 #if !defined(ENABLE_AGENT_INTERFACE)

configure.ac

@@ -41,7 +41,7 @@ AC_ARG_ENABLE([alignment-checks],
 AS_IF([test "x$enable_alignment_checks" = "xyes"],
       [AC_DEFINE([SPICE_DEBUG_ALIGNMENT], 1, [Enable runtime checks for cast alignment])])
 
-SPICE_CHECK_RECORDER
+SPICE_CHECK_INSTRUMENTATION
 
 # Checks for libraries
 PKG_CHECK_MODULES([PROTOCOL], [spice-protocol >= 0.12.12])

m4/spice-deps.m4

@@ -341,17 +341,20 @@ AC_DEFUN([SPICE_CHECK_OPENSSL], [
     PKG_CHECK_MODULES(OPENSSL, openssl)
 ])
 
-# SPICE_CHECK_RECORDER
+# SPICE_CHECK_INSTRUMENTATION
 # -----------------
-# Check for the availability of recorder library.
+# Check for the availability of an instrumentation library.
 #------------------
-AC_DEFUN([SPICE_CHECK_RECORDER], [
-    AC_ARG_ENABLE([recorder],
-      AS_HELP_STRING([--enable-recorder],
-                     [Enable recorder instrumentation @<:@default=no@:>@]),
+AC_DEFUN([SPICE_CHECK_INSTRUMENTATION], [
+    AC_ARG_ENABLE([instrumentation],
+      AS_HELP_STRING([--enable-instrumentation=@<:@recorder/agent/no@:>@],
+                     [Enable instrumentation @<:@default=no@:>@]),
       [],
-      enable_recorder="no")
-    AS_IF([test "$enable_recorder" = "yes"],
-           AC_DEFINE([ENABLE_RECORDER], [1], [Define if recorder instrumentation is enabled]))
-    AM_CONDITIONAL([ENABLE_RECORDER],[test "$enable_recorder" = "yes"])
+      enable_instrumentation="no")
+    AS_IF([test "$enable_instrumentation" = "recorder"],
+           AC_DEFINE([ENABLE_RECORDER], [1], [Define if the recorder instrumentation is enabled]))
+    AS_IF([test "$enable_instrumentation" = "agent"],
+           AC_DEFINE([ENABLE_AGENT_INTERFACE], [1], [Define if the agent-interface instrumentation is enabled]))
+    AM_CONDITIONAL([ENABLE_RECORDER],[test "$enable_instrumentation" = "recorder"])
+    AM_CONDITIONAL([ENABLE_AGENT_INTERFACE],[test "$enable_instrumentation" = "agent"])
 ])

meson.build

@@ -36,9 +36,12 @@ if host_machine.endian() == 'big'
   spice_common_config_data.set('WORDS_BIGENDIAN', '1')
 endif
 
-if get_option('recorder')
+if get_option('instrumentation') == 'recorder'
   spice_common_config_data.set('ENABLE_RECORDER', '1')
 endif
+if get_option('instrumentation') == 'agent'
+  spice_common_config_data.set('ENABLE_AGENT_INTERFACE', '1')
+endif
 
 spice_common_generate_code = get_option('generate-code')
 spice_common_generate_client_code = spice_common_generate_code == 'all' or spice_common_generate_code == 'client'

meson_options.txt

@@ -21,11 +21,11 @@ option('opus',
     yield : true,
     description: 'Enable Opus audio codec')
 
-option('recorder',
-    type : 'boolean',
-    value : false,
-    yield : true,
-    description: 'Enable recorder instrumentation')
+option('instrumentation',
+    type : 'combo',
+    value : 'no',
+    choices : ['recorder', 'agent', 'no'],
+    description: 'Enable instrumentation')
 
 option('smartcard',
     type : 'feature',