Enable metric output plugins

examples/out_gstdout/README.md

@@ -24,6 +24,18 @@ func FLBPluginRegister(ctx unsafe.Pointer) int {
 
 This function is invoked at start time _before_ any configuration is done inside the engine.
 
+### Setting event type 
+
+By default, Fluent Bit Golang plugins process logs. Optionally, the event_type 
+can be set to allow for metrics by using `output.FLBPluginRegisterWithEventType`. 
+
+```go
+//export FLBPluginRegister 
+func FLBPluginRegister(def unsafe.Pointer) int {
+	return output.FLBPluginRegisterWithEventType(ctx, output.FLB_OUTPUT_METRICS, "gstdout", "Stdout GO!")
+}
+```
+
 ## Plugin Initialization
 
 Before the engine starts, it initialize all plugins that were requested to start. Upon initialization a configuration context already exists, so the plugin can ask for configuration parameters or do any other internal checks. E.g:

examples/out_multiinstance/README.md

@@ -29,6 +29,18 @@ func FLBPluginRegister(def unsafe.Pointer) int {
 This function is invoked at start time _before_ any configuration is done
 inside the engine.
 
+### Setting event type 
+
+By default, Fluent Bit Golang plugins process logs. Optionally, the event_type 
+can be set to allow for metrics by using `output.FLBPluginRegisterWithEventType`. 
+
+```go
+//export FLBPluginRegister 
+func FLBPluginRegister(def unsafe.Pointer) int {
+	return output.FLBPluginRegisterWithEventType(ctx, output.FLB_OUTPUT_METRICS, "multiinstance", "Testing multiple instances")
+}
+```
+
 ## Plugin Initialization
 
 Before the engine starts, it initializes all plugins that were configured.

input/flb_plugin.h

@@ -38,6 +38,7 @@ struct flb_plugin_proxy_def {
     int flags;
     char *name;
     char *description;
+    int event_type;
 };
 
 #endif

input/input.go

@@ -52,6 +52,7 @@ func FLBPluginRegister(def unsafe.Pointer, name, desc string) int {
 	p.flags = 0
 	p.name = C.CString(name)
 	p.description = C.CString(desc)
+	p.event_type = 0
 	return 0
 }
 

output/flb_output.h

@@ -20,6 +20,10 @@
 #ifndef FLBGO_OUTPUT_H
 #define FLBGO_OUTPUT_H
 
+#define FLB_OUTPUT_LOGS    1
+#define FLB_OUTPUT_METRICS 2
+#define FLB_OUTPUT_TRACES  4
+
 struct flb_api {
     char *(*output_get_property) (char *, void *);
     char *_;

output/flb_plugin.h

@@ -38,6 +38,7 @@ struct flb_plugin_proxy_def {
     int flags;
     char *name;
     char *description;
+    int  event_type;
 };
 
 #endif

output/output.go

@@ -36,6 +36,9 @@ const (
 
 	FLB_PROXY_OUTPUT_PLUGIN = C.FLB_PROXY_OUTPUT_PLUGIN
 	FLB_PROXY_GOLANG        = C.FLB_PROXY_GOLANG
+	FLB_OUTPUT_LOGS         = C.FLB_OUTPUT_LOGS
+	FLB_OUTPUT_METRICS      = C.FLB_OUTPUT_METRICS
+	FLB_OUTPUT_TRACES       = C.FLB_OUTPUT_TRACES
 )
 
 // Local type to define a plugin definition
@@ -53,6 +56,18 @@ func FLBPluginRegister(def unsafe.Pointer, name, desc string) int {
 	p.flags = 0
 	p.name = C.CString(name)
 	p.description = C.CString(desc)
+	p.event_type = 0
+	return 0
+}
+
+func FLBPluginRegisterWithEventType(def unsafe.Pointer, eventType int, name, desc string) int {
+	p := (*FLBPluginProxyDef)(def)
+	p._type = FLB_PROXY_OUTPUT_PLUGIN
+	p.proxy = FLB_PROXY_GOLANG
+	p.flags = 0
+	p.name = C.CString(name)
+	p.description = C.CString(desc)
+	p.event_type = C.int(eventType)
 	return 0
 }