integration tests: Add helpers to start/stop the manager and engines.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

test/integration/vars.bash

@@ -1,7 +1,76 @@
 #!/bin/bash
 
+# Root directory of the repository.
 SWARM_ROOT=${BATS_TEST_DIRNAME}/../..
 
+# Docker image and version to use for integration tests.
+DOCKER_IMAGE=${DOCKER_IMAGE:-aluzzardi/docker}
+DOCKER_VERSION=${DOCKER_VERSION:-1.5}
+
+# Host on which the manager will listen to (random port between 6000 and 7000).
+SWARM_HOST=127.0.0.1:$(( ( RANDOM % 1000 )  + 6000 ))
+
+# Use a random base port (for engines) between 5000 and 6000.
+BASE_PORT=$(( ( RANDOM % 1000 )  + 5000 ))
+
+# Join an array with a given separator.
+function join { local IFS="$1"; shift; echo "$*"; }
+
+# Run the swarm binary.
 function swarm() {
 	${SWARM_ROOT}/swarm $@
 }
+
+# Waits until the given docker engine API becomes reachable.
+function wait_until_reachable() {
+	local attempts=0
+	until docker -H $1 info &> /dev/null || [ $attempts -ge 10 ]; do
+		echo "Attempt to connect to ${HOSTS[$i]} failed for the $((++attempts)) time" >&2
+		sleep 0.5
+	done
+}
+
+# Start the swarm manager in background.
+function start_manager() {
+	${SWARM_ROOT}/swarm manage -H $SWARM_HOST $@ `join , ${HOSTS[@]}` &
+	SWARM_PID=$!
+	wait_until_reachable $SWARM_HOST
+}
+
+# Stops the manager.
+function stop_manager() {
+	kill $SWARM_PID
+}
+
+# Run the docker CLI against swarm.
+function docker_swarm() {
+	docker -H $SWARM_HOST $@
+}
+
+# Start N docker engines.
+function start_docker() {
+	local current=${#DOCKER_CONTAINERS[@]}
+	local instances="$1"
+	shift
+	local args="$@"
+
+	# Start the engines.
+	for i in `seq $current $((instances - 1))`; do
+		local port=$(($BASE_PORT + $i))
+		HOSTS[$i]=127.0.0.1:$port
+		DOCKER_CONTAINERS[$i]=$(docker run -d --name node-$i -h node-$i --privileged -p 127.0.0.1:$port:$port -it ${DOCKER_IMAGE}:${DOCKER_VERSION} docker -d -H 0.0.0.0:$port $args)
+	done
+
+	# Wait for the engines to be reachable.
+	for i in `seq $current $((instances - 1))`; do
+		wait_until_reachable ${HOSTS[$i]}
+	done
+}
+
+# Stop all engines.
+function stop_docker() {
+	for id in ${DOCKER_CONTAINERS[@]}; do
+		echo "Stopping $id"
+		docker rm -f $id > /dev/null;
+	done
+}