in_mem_metrics: add metrics plugin that tracks RSS and PSS memory for linux.

Add a new metrics plugin that uses /proc/[0-9]+/smaps_rollup to track the RSS,
PSS and shared memory usage of all or some processes on linux.

Signed-off-by: Phillip Whelan <[email protected]>

Author: pwhelan

CMakeLists.txt

@@ -275,6 +275,7 @@ if(FLB_ALL)
   # Input plugins
   set(FLB_IN_CPU          1)
   set(FLB_IN_MEM          1)
+  set(FLB_IN_MEM_METRICS  1)
   set(FLB_IN_KMSG         1)
   set(FLB_IN_MQTT         1)
   set(FLB_IN_SERIAL       1)

cmake/plugins_options.cmake

@@ -36,6 +36,7 @@ DEFINE_OPTION(FLB_IN_KMSG                     "Enable Kernel log input plugin"
 DEFINE_OPTION(FLB_IN_KUBERNETES_EVENTS        "Enable Kubernetes Events plugin"              ON)
 DEFINE_OPTION(FLB_IN_LIB                      "Enable library mode input plugin"             ON)
 DEFINE_OPTION(FLB_IN_MEM                      "Enable Memory input plugin"                   ON)
+DEFINE_OPTION(FLB_IN_MEM_METRICS              "Enable memory metrics input plugin"           ON)
 DEFINE_OPTION(FLB_IN_MQTT                     "Enable MQTT Broker input plugin"              ON)
 DEFINE_OPTION(FLB_IN_NETIF                    "Enable NetworkIF input plugin"                ON)
 DEFINE_OPTION(FLB_IN_NGINX_EXPORTER_METRICS   "Enable Nginx Metrics input plugin"            ON)

cmake/windows-setup.cmake

@@ -54,6 +54,7 @@ if(FLB_WINDOWS_DEFAULTS)
   set(FLB_IN_HEALTH              No)
   set(FLB_IN_HTTP               Yes)
   set(FLB_IN_MEM                 No)
+  set(FLB_IN_MEM_METRICS         No)
   set(FLB_IN_KAFKA              Yes)
   set(FLB_IN_KMSG                No)
   set(FLB_IN_LIB                Yes)

plugins/CMakeLists.txt

@@ -251,6 +251,7 @@ REGISTER_IN_PLUGIN("in_blob")
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
   REGISTER_IN_PLUGIN("in_cpu")
   REGISTER_IN_PLUGIN("in_mem")
+  REGISTER_IN_PLUGIN("in_mem_metrics")
   REGISTER_IN_PLUGIN("in_thermal")
   REGISTER_IN_PLUGIN("in_kmsg")
   REGISTER_IN_PLUGIN("in_proc")

plugins/in_mem_metrics/CMakeLists.txt

@@ -0,0 +1,4 @@
+set(src
+    mem_metrics.c)
+
+FLB_PLUGIN(in_mem_metrics "${src}" "")