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

@@ -170,6 +170,7 @@ option(FLB_IN_FORWARD                  "Enable Forward input plugin"
 option(FLB_IN_HEALTH                   "Enable Health input plugin"                   Yes)
 option(FLB_IN_HTTP                     "Enable HTTP input plugin"                     Yes)
 option(FLB_IN_MEM                      "Enable Memory input plugin"                   Yes)
+option(FLB_IN_MEM_METRICS              "Enable memory metrics input plugin"           Yes)
 option(FLB_IN_KUBERNETES_EVENTS        "Enabke Kubernetes Events plugin"              Yes)
 option(FLB_IN_KAFKA                    "Enable Kafka input plugin"                    Yes)
 option(FLB_IN_KMSG                     "Enable Kernel log input plugin"               Yes)

plugins/CMakeLists.txt

@@ -197,6 +197,7 @@ REGISTER_CUSTOM_PLUGIN("custom_calyptia")
 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}" "")