Signalfx exporter: add translations for filesystem metrics (#584)

Author: dmitryax

exporter/signalfxexporter/factory_test.go

@@ -176,7 +176,7 @@ func TestCreateMetricsExporterWithDefaultTranslaitonRules(t *testing.T) {
 
 	// Validate that default translation rules are loaded
 	// Expected values has to be updated once default config changed
-	assert.Equal(t, 12, len(config.TranslationRules))
+	assert.Equal(t, 14, len(config.TranslationRules))
 	assert.Equal(t, translation.ActionRenameDimensionKeys, config.TranslationRules[0].Action)
 	assert.Equal(t, 20, len(config.TranslationRules[0].Mapping))
 }

exporter/signalfxexporter/translation/constants.go

@@ -182,6 +182,21 @@ translation_rules:
     free: memory.free
     slab_reclaimable: memory.slab_recl
     slab_unreclaimable: memory.slab_unrecl
-    used: memory.used    
+    used: memory.used
+
+# convert filesystem metrics
+- action: split_metric
+  metric_name: system.filesystem.usage
+  dimension_key: state
+  mapping:
+    free: df_complex.free
+    reserved: df_complex.reserved
+    used: df_complex.used
+- action: split_metric
+  metric_name: system.filesystem.inodes.usage
+  dimension_key: state
+  mapping:
+    free: df_inodes.free
+    used: df_inodes.used
 `
 )