fixes + go version bump in __prometheus_exporter (#573)

cdist/conf/type/__prometheus_exporter/man.rst

@@ -16,6 +16,13 @@ Daemontools (or something compatible) must be installed (in particular, the comm
 This type installs and builds the latest version from git, using go get. A recent version of golang as well
 as build tools (make, g++, etc.) must be available.
 
+Currently supported exporters:
+
+- node
+- blackbox
+- ceph
+
+
 REQUIRED PARAMETERS
 -------------------
 None

cdist/conf/type/__prometheus_exporter/manifest

@@ -10,41 +10,40 @@ __user prometheus --system
 case $exporter in
 	node)
 		TEXTFILES=/service/node-exporter/textfiles  # path for the textfiles collector
+		__directory $TEXTFILES --parents --mode 777
+		require="$require __golang_from_vendor" __go_get github.com/prometheus/node_exporter
 
 		port=9100
 		run="setuidgid prometheus $GOBIN/node_exporter -web.listen-address :$port -collector.textfile.directory=$TEXTFILES"
-
-		require="__golang_from_vendor" __go_get github.com/prometheus/node_exporter
-		__directory $TEXTFILES --parents --mode 777
 	;;
 	blackbox)
-		port=9115
-		run="setuidgid prometheus $GOBIN/blackbox_exporter -config.file=/service/blackbox-exporter/blackbox.yml"
-
-		require="__daemontools_service/blackbox-exporter __user/prometheus" __config_file "/service/blackbox-exporter/blackbox.yml" \
+		require="$require __daemontools_service/${exporter}-exporter __user/prometheus" __config_file "/service/${exporter}-exporter/blackbox.yml" \
 			--source $__type/files/blackbox.yml \
 			--group prometheus --mode 640 \
-			--onchange "svc -h /service/blackbox-exporter"
-		require="__golang_from_vendor" __go_get github.com/prometheus/blackbox_exporter
+			--onchange "svc -h /service/${exporter}-exporter"
+		require="$require __golang_from_vendor" __go_get github.com/prometheus/blackbox_exporter
+
+		port=9115
+		run="setuidgid prometheus $GOBIN/blackbox_exporter -config.file=/service/${exporter}-exporter/blackbox.yml"
 	;;
 	ceph)
+		__package librados-dev  # dependency of ceph_exporter
+		require="$require __golang_from_vendor __package/librados-dev" __go_get github.com/digitalocean/ceph_exporter
+
 		port=9128
 		run="setuidgid ceph $GOBIN/ceph_exporter -ceph.config /etc/ceph/ceph.conf -telemetry.addr :$port"
-
-		__package librados-dev  # dependency of ceph_exporter
-		require="__golang_from_vendor __package/librados-dev" __go_get github.com/digitalocean/ceph_exporter
 	;;
 	*)
-		echo "Unknown exporter: $exporter." >&2
+		echo "Unsupported exporter: $exporter." >&2
 		exit 1
 	;;
 esac
 
-require="__daemontools" __daemontools_service ${exporter}-exporter --run "$run"
+require="$require __daemontools" __daemontools_service ${exporter}-exporter --run "$run"
 if [ -f "$__object/parameter/add-consul-service" ]; then
 	__consul_service ${exporter}-exporter --port $port --check-http "http://localhost:$port/metrics" --check-interval 10s
 fi
 
 #__daemontools --install-init-script
 __daemontools
-__golang_from_vendor --version 1.8.1  # required for many exporters
+__golang_from_vendor --version 1.9  # required for many exporters