influxdb output: treat field type conflicts as a successful write

If we write a batch of points and get a "field type conflict" error
message in return, we should drop the entire batch of points because
this indicates that one or more points have a type that doesnt match the
database.

These errors will never go away on their own, and InfluxDB will
successfully write the points that dont have a conflict.

closes #2245

CHANGELOG.md

@@ -70,6 +70,7 @@ plugins, not just statsd.
 - [#1814](https://github.com/influxdata/telegraf/issues/1814): snmp: ensure proper context is present on error messages.
 - [#2299](https://github.com/influxdata/telegraf/issues/2299): opentsdb: add tcp:// prefix if no scheme provided.
 - [#2297](https://github.com/influxdata/telegraf/issues/2297): influx parser: parse line-protocol without newlines.
+- [#2245](https://github.com/influxdata/telegraf/issues/2245): influxdb output: fix field type conflict blocking output buffer.
 
 ## v1.1.2 [2016-12-12]
 

plugins/outputs/influxdb/influxdb.go

@@ -200,8 +200,6 @@ func (i *InfluxDB) Write(metrics []telegraf.Metric) error {
 	p := rand.Perm(len(i.conns))
 	for _, n := range p {
 		if e := i.conns[n].Write(bp); e != nil {
-			// Log write failure
-			log.Printf("E! InfluxDB Output Error: %s", e)
 			// If the database was not found, try to recreate it
 			if strings.Contains(e.Error(), "database not found") {
 				if errc := createDatabase(i.conns[n], i.Database); errc != nil {
@@ -209,6 +207,15 @@ func (i *InfluxDB) Write(metrics []telegraf.Metric) error {
 						i.Database)
 				}
 			}
+			if strings.Contains(e.Error(), "field type conflict") {
+				log.Printf("E! Field type conflict, dropping conflicted points: %s", e)
+				// setting err to nil, otherwise we will keep retrying and points
+				// w/ conflicting types will get stuck in the buffer forever.
+				err = nil
+				break
+			}
+			// Log write failure
+			log.Printf("E! InfluxDB Output Error: %s", e)
 		} else {
 			err = nil
 			break