Allow nightly build script to email failures

nightly.sh

@@ -1,8 +1,35 @@
 #!/bin/bash
 
+SWAKS="/root/swaks"
+
 # Bump this whenever a release branch is created from master
 MASTER_VERSION=0.9.5
 
+# send_failure_notification sends an e-mail with a build failure notification.
+function send_failure_notification {
+    smtp=$1
+    user=$2
+    password=$3
+    to=$4
+    version=$5
+    $SWAKS --auth \
+        --server $smtp \
+        --au $user \
+        --ap $password \
+        --to $to \
+        --h-Subject: "Nightly build has FAILED" \
+        --body "The nightly build has failed, version: $version"
+}
+
+if [ $# -ne 4 ]; then
+    echo "$0 <smtp server> <user> <password> <to>"
+    exit 1
+fi
+SMTP=$1
+USER=$2
+PASSWORD=$3
+TO=$4
+
 REPO_DIR=`mktemp -d`
 echo "Using $REPO_DIR for all work..."
 
@@ -13,5 +40,12 @@ cd $GOPATH/src/github.com/influxdb
 git clone https://github.com/influxdb/influxdb.git
 
 cd $GOPATH/src/github.com/influxdb/influxdb
-NIGHTLY_BUILD=true ./package.sh $MASTER_VERSION-nightly-`git log --pretty=format:'%h' -n 1`
+VERSION="$MASTER_VERSION-nightly-`git log --pretty=format:'%h' -n 1`"
+NIGHTLY_BUILD=true ./package.sh $VERSION
+
+if [ $? -ne 0 ]; then
+    # Send notification e-mail.
+    send_failure_notification $SMTP $USER $PASSWORD $TO $VERSION
+fi
+
 rm -rf $REPO_DIR