Get rid of app.config

app.config has been a long standing erroneous file in rebar. Erlang/OTP
documentation suggests a sys.config file instead. This file is stored in
the releases/VSN directory. This does a few things but most importantly
it ensures your config (contained in the application environment)
survives a hot upgrade. It also has the advantage of allowing the
configuration of the application to be versioned along side the
application code. This patch flips rebar to use sys.config rather than
app.config.

Additionally it makes this flip to vm.args as well, making them
versioned just like sys.config.

This patch also includes runner script changes to support the old
etc/app.config config file location and support for Windows.

Thanks to mokele for the initial work and kick in the pants to make this
finially happen.

3 files changed, 17 insertions, 4 deletions

diff --git a/test/upgrade_project/rel/files/dummy b/test/upgrade_project/rel/files/dummy
index bacce8d..78d6bae 100755
--- a/test/upgrade_project/rel/files/dummy
+++ b/test/upgrade_project/rel/files/dummy
@@ -50,6 +50,20 @@ 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"
 
+# Use releases/VSN/sys.config if it exists otherwise use etc/app.config
+if [ -e "$RUNNER_BASE_DIR/releases/$APP_VSN/sys.config" ]; then
+    CONFIG_PATH="$RUNNER_BASE_DIR/releases/$APP_VSN/sys.config"
+else
+    CONFIG_PATH="$RUNNER_ETC_DIR/app.config"
+fi
+
+# Use releases/VSN/vm.args if it exists otherwise use etc/vm.args
+if [-e "$RUNNER_BASE_DIR/releases/$APP_VSN/vm.args" ]; then
+    VMARGS_PATH="$RUNNER_BASE_DIR/releases/$APP_VSN/vm.args"
+else
+    VMARGS_PATH="$RUNNER_ETC_DIR/vm.args"
+fi
+
 # Check the first argument for instructions
 case "$1" in
     start)
@@ -147,7 +161,7 @@ case "$1" in
         BINDIR=$ROOTDIR/erts-$ERTS_VSN/bin
         EMU=beam
         PROGNAME=`echo $0 | sed 's/.*\\///'`
-        CMD="$BINDIR/erlexec -boot $RUNNER_BASE_DIR/releases/$APP_VSN/$BOOTFILE -mode embedded -config $RUNNER_ETC_DIR/app.config -args_file $RUNNER_ETC_DIR/vm.args -- ${1+"$@"}"
+        CMD="$BINDIR/erlexec -boot $RUNNER_BASE_DIR/releases/$APP_VSN/$BOOTFILE -mode embedded -config $CONFIG_PATH -args_file $VMARGS_PATH -- ${1+"$@"}"
         export EMU
         export ROOTDIR
         export BINDIR
diff --git a/test/upgrade_project/rel/files/app.config b/test/upgrade_project/rel/files/sys.config
index 3b7f6bd..d7677e7 100644
--- a/test/upgrade_project/rel/files/app.config
+++ b/test/upgrade_project/rel/files/sys.config
@@ -8,4 +8,3 @@
          {error_logger_mf_maxfiles, 5}           % 5 files max
         ]}
 ].
-
diff --git a/test/upgrade_project/rel/reltool.config b/test/upgrade_project/rel/reltool.config
index 22cec5e..9672abc 100644
--- a/test/upgrade_project/rel/reltool.config
+++ b/test/upgrade_project/rel/reltool.config
@@ -20,6 +20,6 @@
           {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"}
+          {copy, "files/sys.config", "releases/\{\{rel_vsn\}\}/sys.config"},
+          {copy, "files/vm.args", "releases/\{\{rel_vsn\}\}/vm.args"}
           ]}.