bst-here: Allow users to specify additional volumes to mount

One may want to mount additional volumes to preserve certain directories
or to share some data between the host and the container. Allow users to
do so by providing a `-v` option that passes its arguments to
corresponding `-v`/`--volume` option for `docker run` command.

Part of #378.

contrib/bst-here

@@ -25,7 +25,7 @@
 usage() {
     cat <<EOF
 
-USAGE: $(basename "$0") [-i BST_HERE_IMAGE] [-p] [-t] [-T] [-h] [COMMAND] [ARG..]
+USAGE: $(basename "$0") [-i BST_HERE_IMAGE] [-p] [-t] [-T] [-v VOLUME ...] [-h] [COMMAND] [ARG..]
 
 Run a bst command in a new BuildStream container.
 
@@ -38,6 +38,8 @@ OPTIONS:
     -p            Pull the latest buildstream image before running.
     -t            Force pseudo-terminal allocation.
     -T            Disable pseudo-terminal allocation.
+    -v VOLUME     Specify additional volumes to mount; should be in format
+                  'host-src:container-dest' same as 'docker run -v'.
     -h            Print this help text and exit.
 
 EOF
@@ -48,13 +50,14 @@ bst_here_image="${BST_HERE_IMAGE:-buildstream/buildstream-fedora:latest}"
 
 is_tty=
 update=false
+extra_volumes_opt=
 
 if test -t 0
 then
     is_tty=y
 fi
 
-while getopts i:ptTh arg
+while getopts i:ptTv:h arg
 do
     case $arg in
     i)
@@ -69,6 +72,9 @@ do
     t)
         is_tty=y
         ;;
+    v)
+        extra_volumes_opt="$extra_volumes_opt --volume $OPTARG"
+        ;;
     h)
         usage 0
         ;;
@@ -121,6 +127,7 @@ exec docker run --rm -i${is_tty:+ -t} \
                 --volume buildstream-cache:/root/.cache/buildstream \
                 --volume buildstream-config:/root/.config \
                 --volume "$PWD":/src \
+                $extra_volumes_opt \
                 --workdir /src \
                 "$bst_here_image" \
                 $command