Add 'generate-upgrade' command

To support OTP release upgrades I have added support for building
upgrade packages. Support for this is included in the
rebar_upgrade module, specifically generate_upgrade/2. It requires
one variable to be set on the command line 'previous_release' which
is the absolute path or relative path from 'rel/' to the previous
release one is upgrading from. Running an upgrade will create the
needed files, including a relup and result in a tarball containing
the upgrade being written to 'rel/'. When done it cleans up the
temporary files systools created.

Usage:
$ rebar generate-upgrade previous_release=/path/to/old/version

This also includes a dummy application that can be used to test
upgrades as well as an example.

Special thanks to Daniel Reverri, Jesper Louis Andersen and
Richard Jones for comments and patches.

1 files changed, 155 insertions, 0 deletions

diff --git a/test/upgrade_project/rel/files/dummy b/test/upgrade_project/rel/files/dummy
new file mode 100755
index 0000000..ec6d7ff
--- /dev/null
+++ b/test/upgrade_project/rel/files/dummy
@@ -0,0 +1,155 @@
+#!/bin/bash
+# -*- tab-width:4;indent-tabs-mode:nil -*-
+# ex: ts=4 sw=4 et
+
+RUNNER_SCRIPT_DIR=$(cd ${0%/*} && pwd)
+
+RUNNER_BASE_DIR=${RUNNER_SCRIPT_DIR%/*}
+RUNNER_ETC_DIR=$RUNNER_BASE_DIR/etc
+RUNNER_LOG_DIR=$RUNNER_BASE_DIR/log
+PIPE_DIR=/tmp/$RUNNER_BASE_DIR/
+RUNNER_USER=
+
+# Make sure this script is running as the appropriate user
+if [ ! -z "$RUNNER_USER" ] && [ `whoami` != "$RUNNER_USER" ]; then
+    exec sudo -u $RUNNER_USER -i $0 $@
+fi
+
+# Make sure CWD is set to runner base dir
+cd $RUNNER_BASE_DIR
+
+# Make sure log directory exists
+mkdir -p $RUNNER_LOG_DIR
+
+# Extract the target node name from node.args
+NAME_ARG=`grep -e '-[s]*name' $RUNNER_ETC_DIR/vm.args`
+if [ -z "$NAME_ARG" ]; then
+    echo "vm.args needs to have either -name or -sname parameter."
+    exit 1
+fi
+
+# Extract the target cookie
+COOKIE_ARG=`grep -e '-setcookie' $RUNNER_ETC_DIR/vm.args`
+if [ -z "$COOKIE_ARG" ]; then
+    echo "vm.args needs to have a -setcookie parameter."
+    exit 1
+fi
+
+# Identify the script name
+SCRIPT=`basename $0`
+
+# Parse out release and erts info
+START_ERL=`cat $RUNNER_BASE_DIR/releases/start_erl.data`
+ERTS_VSN=${START_ERL% *}
+APP_VSN=${START_ERL#* }
+
+# Add ERTS bin dir to our path
+ERTS_PATH=$RUNNER_BASE_DIR/erts-$ERTS_VSN/bin
+
+# Setup command to control the node
+NODETOOL="$ERTS_PATH/escript $ERTS_PATH/nodetool $NAME_ARG $COOKIE_ARG"
+
+# Check the first argument for instructions
+case "$1" in
+    start)
+        # Make sure there is not already a node running
+        RES=`$NODETOOL ping`
+        if [ "$RES" = "pong" ]; then
+            echo "Node is already running!"
+            exit 1
+        fi
+        HEART_COMMAND="$RUNNER_BASE_DIR/bin/$SCRIPT start"
+        export HEART_COMMAND
+        mkdir -p $PIPE_DIR
+        # Note the trailing slash on $PIPE_DIR/
+        $ERTS_PATH/run_erl -daemon $PIPE_DIR/ $RUNNER_LOG_DIR "exec $RUNNER_BASE_DIR/bin/$SCRIPT console" 2>&1
+        ;;
+
+    stop)
+        # Wait for the node to completely stop...
+        case `uname -s` in
+            Linux|Darwin|FreeBSD|DragonFly|NetBSD|OpenBSD)
+                # PID COMMAND
+                PID=`ps ax -o pid= -o command=|\
+                    grep "$RUNNER_BASE_DIR/.*/[b]eam"|awk '{print $1}'`
+                ;;
+            SunOS)
+                # PID COMMAND
+                PID=`ps -ef -o pid= -o args=|\
+                    grep "$RUNNER_BASE_DIR/.*/[b]eam"|awk '{print $1}'`
+                ;;
+            CYGWIN*)
+                # UID PID PPID TTY STIME COMMAND
+                PID=`ps -efW|grep "$RUNNER_BASE_DIR/.*/[b]eam"|awk '{print $2}'`
+                ;;
+        esac
+        $NODETOOL stop
+        while `kill -0 $PID 2>/dev/null`;
+        do
+            sleep 1
+        done
+        ;;
+
+    restart)
+        ## Restart the VM without exiting the process
+        $NODETOOL restart
+        ;;
+
+    reboot)
+        ## Restart the VM completely (uses heart to restart it)
+        $NODETOOL reboot
+        ;;
+
+    ping)
+        ## See if the VM is alive
+        $NODETOOL ping
+        ;;
+
+    attach)
+        # Make sure a node IS running
+        RES=`$NODETOOL ping`
+        if [ "$RES" != "pong" ]; then
+            echo "Node is not running!"
+            exit 1
+        fi
+
+        shift
+        $ERTS_PATH/to_erl $PIPE_DIR
+        ;;
+
+    console|console_clean)
+        # .boot file typically just $SCRIPT (ie, the app name)
+        # however, for debugging, sometimes start_clean.boot is useful:
+        case "$1" in
+            console)        BOOTFILE=$SCRIPT ;;
+            console_clean)  BOOTFILE=start_clean ;;
+        esac
+        # Setup beam-required vars
+        ROOTDIR=$RUNNER_BASE_DIR
+        BINDIR=$ROOTDIR/erts-$ERTS_VSN/bin
+        EMU=beam
+        PROGNAME=`echo $0 | sed 's/.*\\///'`
+        CMD="$BINDIR/erlexec -boot $RUNNER_BASE_DIR/releases/$APP_VSN/$BOOTFILE -embedded -config $RUNNER_ETC_DIR/app.config -args_file $RUNNER_ETC_DIR/vm.args -- ${1+"$@"}"
+        export EMU
+        export ROOTDIR
+        export BINDIR
+        export PROGNAME
+
+        # Dump environment info for logging purposes
+        echo "Exec: $CMD"
+        echo "Root: $ROOTDIR"
+
+        # Log the startup
+        logger -t "$SCRIPT[$$]" "Starting up"
+
+        # Start the VM
+        exec $CMD
+        ;;
+
+    *)
+        echo "Usage: $SCRIPT {start|stop|restart|reboot|ping|console|attach}"
+        exit 1
+        ;;
+esac
+
+exit 0