add unpack option to install escript

priv/templates/extended_bin.dtl

@@ -267,7 +267,27 @@ case "$1" in
         fi
 
         exec "$BINDIR/escript" "$ROOTDIR/bin/install_upgrade.escript" \
-             "$REL_NAME" "$NAME" "$COOKIE" "$2"
+             "install" "$REL_NAME" "$NAME" "$COOKIE" "$2"
+        ;;
+
+    unpack)
+        if [ -z "$2" ]; then
+            echo "Missing package argument"
+            echo "Usage: $REL_NAME $1 {package base name}"
+            echo "NOTE {package base name} MUST NOT include the .tar.gz suffix"
+            exit 1
+        fi
+
+        # Make sure a node IS running
+        relx_nodetool "ping" > /dev/null
+        ES="$?"
+        if [ "$ES" -ne 0 ]; then
+            echo "Node is not running!"
+            exit $ES
+        fi
+
+        exec "$BINDIR/escript" "$ROOTDIR/bin/install_upgrade.escript" \
+             "unpack" "$REL_NAME" "$NAME" "$COOKIE" "$2"
         ;;
 
     console|console_clean|console_boot)

priv/templates/install_upgrade_escript.dtl

@@ -6,8 +6,36 @@
 -define(TIMEOUT, 300000).
 -define(INFO(Fmt,Args), io:format(Fmt,Args)).
 
-%% Upgrades, to a new tar.gz release
-main([RelName, NodeName, Cookie, VersionArg]) ->
+%% Unpack or upgrade to a new tar.gz release
+main(["unpack", RelName, NodeName, Cookie, VersionArg]) ->
+    TargetNode = start_distribution(NodeName, Cookie),
+    WhichReleases = which_releases(TargetNode),
+    Version = parse_version(VersionArg),
+    case proplists:get_value(Version, WhichReleases) of
+        undefined ->
+            %% not installed, so unpack tarball:
+            ?INFO("Release ~s not found, attempting to unpack releases/~s/~s.tar.gz~n",[Version,Version,RelName]),
+            ReleasePackage = Version ++ "/" ++ RelName,
+            case rpc:call(TargetNode, release_handler, unpack_release,
+                          [ReleasePackage], ?TIMEOUT) of
+                {ok, Vsn} ->
+                    ?INFO("Unpacked successfully: ~p~n", [Vsn]);
+                {error, UnpackReason} ->
+                    print_existing_versions(TargetNode),
+                    ?INFO("Unpack failed: ~p~n",[UnpackReason]),
+                    erlang:halt(2)
+            end;
+        old ->
+            %% no need to unpack, has been installed previously
+            ?INFO("Release ~s is marked old, switching to it.~n",[Version]);
+        unpacked ->
+            ?INFO("Release ~s is already unpacked, now installing.~n",[Version]);
+        current ->
+            ?INFO("Release ~s is already installed and current. Making permanent.~n",[Version]);
+        permanent ->
+            ?INFO("Release ~s is already installed, and set permanent.~n",[Version])
+    end;
+main(["install", RelName, NodeName, Cookie, VersionArg]) ->
     TargetNode = start_distribution(NodeName, Cookie),
     WhichReleases = which_releases(TargetNode),
     Version = parse_version(VersionArg),