Ensure tests pass now that we're passing fstype around

go fmt checks

Rework the example configuration snippets

README.md

@@ -91,7 +91,7 @@ This is tested on metrics that have passed the tagpass test.
 global interval, but if one particular plugin should be run less or more often,
 you can configure that here.
 
-### Plugin Configuration Example
+### Plugin Configuration Examples
 
 ```
 # Read metrics about disk usage by mount point
@@ -102,13 +102,21 @@ interval = "1m" # Run at a 1 minute interval instead of the default
 # These tag conditions are OR, not AND.
 # If the (filesystem is ext4 or xfs) or (the path is /opt or /home) then the metric passes
 fstype = [ "ext4", "xfs" ]
-path = [ "/", /opt", "/home" ]
+path = [ "/opt", "/home" ]
 
-# Any metrics that succeed at 'tagpass' are then checked to see if they should be dropped
+[postgresql]
+
+[postgresql.tagdrop]
+# Don't report stats about the database name 'testdatabase'
+db = [ "testdatabase" ]
+
+```
+
+```
+[disk]
+# Don't report stats about the following filesystem types
 [disk.tagdrop]
-# Drop the root mountpoint from the metrics
-path = [ "/" ]
-
+fstype = [ "nfs", "tmpfs", "ecryptfs" ]
 ```
 
 ## Plugins

plugins/system/ps/disk/disk_test.go

@@ -59,6 +59,7 @@ func TestDisk_io_counters(t *testing.T) {
 func TestDiskUsageStat_String(t *testing.T) {
 	v := DiskUsageStat{
 		Path:              "/",
+		Fstype:            "ext4",
 		Total:             1000,
 		Free:              2000,
 		Used:              3000,
@@ -68,7 +69,7 @@ func TestDiskUsageStat_String(t *testing.T) {
 		InodesFree:        6000,
 		InodesUsedPercent: 49.1,
 	}
-	e := `{"path":"/","total":1000,"free":2000,"used":3000,"used_percent":50.1,"inodes_total":4000,"inodes_used":5000,"inodes_free":6000,"inodes_used_percent":49.1}`
+	e := `{"path":"/","fstype":"ext4","total":1000,"free":2000,"used":3000,"used_percent":50.1,"inodes_total":4000,"inodes_used":5000,"inodes_free":6000,"inodes_used_percent":49.1}`
 	if e != fmt.Sprintf("%v", v) {
 		t.Errorf("DiskUsageStat string is invalid: %v", v)
 	}

plugins/system/system_test.go

@@ -48,6 +48,7 @@ func TestSystemStats_GenerateStats(t *testing.T) {
 
 	du := &disk.DiskUsageStat{
 		Path:        "/",
+		Fstype:      "ext4",
 		Total:       128,
 		Free:        23,
 		InodesTotal: 1234,
@@ -195,7 +196,8 @@ func TestSystemStats_GenerateStats(t *testing.T) {
 	require.NoError(t, err)
 
 	tags := map[string]string{
-		"path": "/",
+		"path":   "/",
+		"fstype": "ext4",
 	}
 
 	assert.True(t, acc.CheckTaggedValue("total", uint64(128), tags))