Merge ~pjdc/influxdb-charm/+git/influxdb-charm:back-up-with-ancient-clients into influxdb-charm:master

[Paul Collins]

[Haw Loeung (hloeung)]

LGTM, +1

review: Approve

diff --git a/templates/influxdb-backup b/templates/influxdb-backup
index cb53a44..cd3fabf 100644
--- a/templates/influxdb-backup
+++ b/templates/influxdb-backup
@@ -17,7 +17,20 @@ if [ -r /root/.influx-auth ]; then
     export INFLUX_USERNAME INFLUX_PASSWORD
 fi
 
-DATABASES=$(influx --execute 'show databases' --format=json | jq --raw-output '.results[0].series[0].values[][0]' | grep -ve '^_internal$')
+# Leak credentials only when necessary.  Support
+# for the environment variables was added in
+# version 1.1.0.  Note that earlier versions of the
+# shell display their version differently.
+auth_args=""
+case $(influx -version) in
+    "InfluxDB shell version: 1.0."*|"InfluxDB shell 0."*)
+	auth_args="-username ${INFLUX_USERNAME} -password ${INFLUX_PASSWORD}"
+	;;
+    *)
+	;;
+esac
+
+DATABASES=$(influx ${auth_args} --execute 'show databases' --format=json | jq --raw-output '.results[0].series[0].values[][0]' | grep -ve '^_internal$')
 
 # back up metadata
 influxd backup $TODAY_DIR/metdata