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.

13 files changed, 499 insertions, 0 deletions

diff --git a/test/upgrade_project/README.md b/test/upgrade_project/README.md
new file mode 100644
index 0000000..cf753e8
--- /dev/null
+++ b/test/upgrade_project/README.md
@@ -0,0 +1,38 @@
+#### Building version 0.1
+    rebar compile
+    rebar generate
+    mv rel/dummy rel/dummy_0.1
+    rebar clean
+    # start the release:
+    cd rel/dummy_0.1
+    bin/dummy console
+
+    erl> dummy_server:get_state().
+    erl> dummy_server:set_state(123).
+    erl> dummy_server:get_state().
+
+#### Building version 0.2
+
+    # Now, in another terminal we prepare an upgrade..
+
+    # change release version numbers from 0.1 to 0.2 in
+    $EDITOR apps/dummy/src/dummy.app.src
+    $EDITOR rel/reltool.config
+
+    rebar compile
+    rebar generate
+    rebar generate-upgrade previous_release=dummy_0.1
+    tar -zvtf rel/dummy_0.2.tar.gz
+
+
+#### Deploying with release_handler
+    mv rel/dummy_0.2.tar.gz rel/dummy_0.1/releases/
+
+    # Now use release_handler in the running erlang console for the deploy:
+
+    erl> release_handler:unpack_release("dummy_0.2").
+    erl> release_handler:install_release("0.2").
+    erl> release_handler:make_permanent("0.2").
+
+    erl> release_handler:which_releases().
+    erl> dummy_server:get_state().
diff --git a/test/upgrade_project/apps/dummy/ebin/dummy.appup b/test/upgrade_project/apps/dummy/ebin/dummy.appup
new file mode 100644
index 0000000..e77f66f
--- /dev/null
+++ b/test/upgrade_project/apps/dummy/ebin/dummy.appup
@@ -0,0 +1,8 @@
+{"0.2",
+    [{"0.1",[
+                {update, dummy_server, {advanced, [foo]}}
+            ]}],
+    [{"0.1",[
+                {update, dummy_server, {advanced, [foo]}}
+            ]}]
+}.
diff --git a/test/upgrade_project/apps/dummy/src/dummy.app.src b/test/upgrade_project/apps/dummy/src/dummy.app.src
new file mode 100644
index 0000000..dd06752
--- /dev/null
+++ b/test/upgrade_project/apps/dummy/src/dummy.app.src
@@ -0,0 +1,9 @@
+{application, dummy, [
+    {description, "a dummy app"},
+    {vsn, "0.1"},
+    {registered, [
+      dummy_app
+    ]},
+    {mod, {dummy_app, []}},
+    {applications, [kernel, stdlib, sasl]}
+]}.
diff --git a/test/upgrade_project/apps/dummy/src/dummy_app.erl b/test/upgrade_project/apps/dummy/src/dummy_app.erl
new file mode 100644
index 0000000..51363b3
--- /dev/null
+++ b/test/upgrade_project/apps/dummy/src/dummy_app.erl
@@ -0,0 +1,9 @@
+-module(dummy_app).
+-behaviour(application).
+
+-export([start/2, stop/1]).
+
+start(_,_) ->
+    dummy_sup:start_link().
+
+stop(_) -> ok.
diff --git a/test/upgrade_project/apps/dummy/src/dummy_server.erl b/test/upgrade_project/apps/dummy/src/dummy_server.erl
new file mode 100644
index 0000000..382251e
--- /dev/null
+++ b/test/upgrade_project/apps/dummy/src/dummy_server.erl
@@ -0,0 +1,56 @@
+-module(dummy_server).
+-behaviour(gen_server).
+
+-export([start_link/0, set_state/1, get_state/0]).
+
+-export([init/1,
+         handle_call/3,
+         handle_cast/2,
+         handle_info/2,
+         terminate/2,
+         code_change/3]).
+
+%%
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+set_state(What) ->
+    gen_server:call(?MODULE, {set_state, What}).
+
+get_state() ->
+    gen_server:call(?MODULE, get_state).
+
+
+%%
+
+init([]) ->
+    say("init, setting state to 0", []),
+    {ok, 0}.
+
+
+handle_call({set_state, NewState}, _From, _State) ->
+    {reply, {ok, NewState}, NewState};
+
+handle_call(get_state, _From, State) ->
+    {reply, State, State}.
+
+handle_cast('__not_implemented', State) ->
+    {noreply, State}.
+
+handle_info(_Info, State) ->
+    say("info ~p, ~p.", [_Info, State]),
+    {noreply, State}.
+
+terminate(_Reason, _State) ->
+    say("terminate ~p, ~p", [_Reason, _State]),
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    say("code_change ~p, ~p, ~p", [_OldVsn, State, _Extra]),
+    {ok, State}.
+
+%% Internal
+
+say(Format, Data) ->
+    io:format("~p:~p: ~s~n", [?MODULE, self(), io_lib:format(Format, Data)]).
diff --git a/test/upgrade_project/apps/dummy/src/dummy_sup.erl b/test/upgrade_project/apps/dummy/src/dummy_sup.erl
new file mode 100644
index 0000000..b5617c7
--- /dev/null
+++ b/test/upgrade_project/apps/dummy/src/dummy_sup.erl
@@ -0,0 +1,15 @@
+-module(dummy_sup).
+-behaviour(supervisor).
+
+-export([start_link/0]).
+-export([init/1]).
+
+start_link() ->
+    supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+init([]) ->
+    Dummy = {dummy_server,
+             {dummy_server, start_link, []},
+             permanent, 5000, worker, [dummy_server]},
+
+    {ok, {{one_for_one, 10, 10}, [Dummy]}}.
diff --git a/test/upgrade_project/rebar.config b/test/upgrade_project/rebar.config
new file mode 100644
index 0000000..11b5b9a
--- /dev/null
+++ b/test/upgrade_project/rebar.config
@@ -0,0 +1,4 @@
+{sub_dirs, [
+    "apps/dummy",
+    "rel"
+]}.
diff --git a/test/upgrade_project/rel/files/app.config b/test/upgrade_project/rel/files/app.config
new file mode 100644
index 0000000..25a3bb3
--- /dev/null
+++ b/test/upgrade_project/rel/files/app.config
@@ -0,0 +1,10 @@
+[
+ %% SASL config
+ {sasl, [
+         {sasl_error_logger, {file, "log/sasl-error.log"}},
+         {errlog_type, error},
+         {error_logger_mf_dir, "log/sasl"},      % Log directory
+         {error_logger_mf_maxbytes, 10485760},   % 10 MB max file size
+         {error_logger_mf_maxfiles, 5}           % 5 files max
+         ]}
+].
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
diff --git a/test/upgrade_project/rel/files/erl b/test/upgrade_project/rel/files/erl
new file mode 100755
index 0000000..b985f23
--- /dev/null
+++ b/test/upgrade_project/rel/files/erl
@@ -0,0 +1,34 @@
+#!/bin/bash
+
+## This script replaces the default "erl" in erts-VSN/bin. This is necessary
+## as escript depends on erl and in turn, erl depends on having access to a
+## bootscript (start.boot). Note that this script is ONLY invoked as a side-effect
+## of running escript -- the embedded node bypasses erl and uses erlexec directly
+## (as it should).
+##
+## Note that this script makes the assumption that there is a start_clean.boot
+## file available in $ROOTDIR/release/VSN.
+
+# Determine the abspath of where this script is executing from.
+ERTS_BIN_DIR=$(cd ${0%/*} && pwd)
+
+# Now determine the root directory -- this script runs from erts-VSN/bin,
+# so we simply need to strip off two dirs from the end of the ERTS_BIN_DIR
+# path.
+ROOTDIR=${ERTS_BIN_DIR%/*/*}
+
+# Parse out release and erts info
+START_ERL=`cat $ROOTDIR/releases/start_erl.data`
+ERTS_VSN=${START_ERL% *}
+APP_VSN=${START_ERL#* }
+
+BINDIR=$ROOTDIR/erts-$ERTS_VSN/bin
+EMU=beam
+PROGNAME=`echo $0 | sed 's/.*\\///'`
+CMD="$BINDIR/erlexec"
+export EMU
+export ROOTDIR
+export BINDIR
+export PROGNAME
+
+exec $CMD -boot $ROOTDIR/releases/$APP_VSN/start_clean ${1+"$@"}
diff --git a/test/upgrade_project/rel/files/nodetool b/test/upgrade_project/rel/files/nodetool
new file mode 100755
index 0000000..cb524ce
--- /dev/null
+++ b/test/upgrade_project/rel/files/nodetool
@@ -0,0 +1,116 @@
+%% -*- mode:erlang;tab-width:4;erlang-indent-level:4;indent-tabs-mode:nil -*-
+%% ex: ft=erlang ts=4 sw=4 et
+%% -------------------------------------------------------------------
+%%
+%% nodetool: Helper Script for interacting with live nodes
+%%
+%% -------------------------------------------------------------------
+
+main(Args) ->
+    %% Extract the args
+    {RestArgs, TargetNode} = process_args(Args, [], undefined),
+
+    %% See if the node is currently running  -- if it's not, we'll bail
+    case {net_kernel:hidden_connect_node(TargetNode), net_adm:ping(TargetNode)} of
+        {true, pong} ->
+            ok;
+        {_, pang} ->
+            io:format("Node ~p not responding to pings.\n", [TargetNode]),
+            halt(1)
+    end,
+
+    case RestArgs of
+        ["ping"] ->
+            %% If we got this far, the node already responsed to a ping, so just dump
+            %% a "pong"
+            io:format("pong\n");
+        ["stop"] ->
+            io:format("~p\n", [rpc:call(TargetNode, init, stop, [], 60000)]);
+        ["restart"] ->
+            io:format("~p\n", [rpc:call(TargetNode, init, restart, [], 60000)]);
+        ["reboot"] ->
+            io:format("~p\n", [rpc:call(TargetNode, init, reboot, [], 60000)]);
+        ["rpc", Module, Function | RpcArgs] ->
+            case rpc:call(TargetNode, list_to_atom(Module), list_to_atom(Function),
+                          [RpcArgs], 60000) of
+                ok ->
+                    ok;
+                {badrpc, Reason} ->
+                    io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
+                    halt(1);
+                _ ->
+                    halt(1)
+            end;
+        ["rpcterms", Module, Function, ArgsAsString] ->
+            case rpc:call(TargetNode, list_to_atom(Module), list_to_atom(Function),
+                          consult(ArgsAsString), 60000) of
+                {badrpc, Reason} ->
+                    io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
+                    halt(1);
+                Other ->
+                    io:format("~p\n", [Other])
+            end;
+        Other ->
+            io:format("Other: ~p\n", [Other]),
+            io:format("Usage: nodetool {ping|stop|restart|reboot}\n")
+    end,
+    net_kernel:stop().
+
+process_args([], Acc, TargetNode) ->
+    {lists:reverse(Acc), TargetNode};
+process_args(["-setcookie", Cookie | Rest], Acc, TargetNode) ->
+    erlang:set_cookie(node(), list_to_atom(Cookie)),
+    process_args(Rest, Acc, TargetNode);
+process_args(["-name", TargetName | Rest], Acc, _) ->
+    ThisNode = append_node_suffix(TargetName, "_maint_"),
+    {ok, _} = net_kernel:start([ThisNode, longnames]),
+    process_args(Rest, Acc, nodename(TargetName));
+process_args(["-sname", TargetName | Rest], Acc, _) ->
+    ThisNode = append_node_suffix(TargetName, "_maint_"),
+    {ok, _} = net_kernel:start([ThisNode, shortnames]),
+    process_args(Rest, Acc, nodename(TargetName));
+process_args([Arg | Rest], Acc, Opts) ->
+    process_args(Rest, [Arg | Acc], Opts).
+
+
+nodename(Name) ->
+    case string:tokens(Name, "@") of
+        [_Node, _Host] ->
+            list_to_atom(Name);
+        [Node] ->
+            [_, Host] = string:tokens(atom_to_list(node()), "@"),
+            list_to_atom(lists:concat([Node, "@", Host]))
+    end.
+
+append_node_suffix(Name, Suffix) ->
+    case string:tokens(Name, "@") of
+        [Node, Host] ->
+            list_to_atom(lists:concat([Node, Suffix, os:getpid(), "@", Host]));
+        [Node] ->
+            list_to_atom(lists:concat([Node, Suffix, os:getpid()]))
+    end.
+
+
+%%
+%% Given a string or binary, parse it into a list of terms, ala file:consult/0
+%%
+consult(Str) when is_list(Str) ->
+    consult([], Str, []);
+consult(Bin) when is_binary(Bin)->
+    consult([], binary_to_list(Bin), []).
+
+consult(Cont, Str, Acc) ->
+    case erl_scan:tokens(Cont, Str, 0) of
+        {done, Result, Remaining} ->
+            case Result of
+                {ok, Tokens, _} ->
+                    {ok, Term} = erl_parse:parse_term(Tokens),
+                    consult([], Remaining, [Term | Acc]);
+                {eof, _Other} ->
+                    lists:reverse(Acc);
+                {error, Info, _} ->
+                    {error, Info}
+            end;
+        {more, Cont1} ->
+            consult(Cont1, eof, Acc)
+    end.
diff --git a/test/upgrade_project/rel/files/vm.args b/test/upgrade_project/rel/files/vm.args
new file mode 100644
index 0000000..7448fb1
--- /dev/null
+++ b/test/upgrade_project/rel/files/vm.args
@@ -0,0 +1,20 @@
+
+## Name of the node
+-name dummy@127.0.0.1
+
+## Cookie for distributed erlang
+-setcookie dummy
+
+## Heartbeat management; auto-restarts VM if it dies or becomes unresponsive
+## (Disabled by default..use with caution!)
+##-heart
+
+## Enable kernel poll and a few async threads
++K true
++A 5
+
+## Increase number of concurrent ports/sockets
+-env ERL_MAX_PORTS 4096
+
+## Tweak GC to run more often
+-env ERL_FULLSWEEP_AFTER 10
diff --git a/test/upgrade_project/rel/reltool.config b/test/upgrade_project/rel/reltool.config
new file mode 100644
index 0000000..22cec5e
--- /dev/null
+++ b/test/upgrade_project/rel/reltool.config
@@ -0,0 +1,25 @@
+{sys, [
+    {lib_dirs, ["../apps"]},
+    {rel, "dummy", "0.1", [
+        kernel,
+        stdlib,
+        sasl,
+        dummy
+    ]},
+    {rel, "start_clean", "", [kernel, stdlib]},
+    {boot_rel, "dummy"},
+    {profile, embedded},
+    {excl_sys_filters, ["^bin/.*", "^erts.*/bin/(dialyzer|typer)"]},
+    {excl_archive_filters, [".*"]},
+
+    {app, dummy, [{incl_cond, include}]}
+]}.
+
+{overlay, [
+          {mkdir, "log/sasl"},
+          {copy, "files/erl", "{{erts_vsn}}/bin/erl"},
+          {copy, "files/nodetool", "{{erts_vsn}}/bin/nodetool"},
+          {copy, "files/dummy", "bin/dummy"},
+          {copy, "files/app.config", "etc/app.config"},
+          {copy, "files/vm.args", "etc/vm.args"}
+          ]}.