contrib/bst-here: Change how invocation works

If run with no arguments, `bst-here` now opens an interactive Bash
shell. This has several advantages to running each `bst` command
in a new container:

  * it's faster
  * bash completions will work
  * man pages could work (if the user runs `dnf install man`)

If run with arguments, those are now assumed to be arguments for `bst`
such that instead of running `bst-here bst build foo` you now just run
`bst-here build foo`.

2 files changed, 17 insertions, 10 deletions

diff --git a/contrib/bst-here b/contrib/bst-here
index 595807df4..6b4e6b2f7 100755
--- a/contrib/bst-here
+++ b/contrib/bst-here
@@ -58,6 +58,12 @@ done
 
 BST_HERE_PS1="\[\033[01;34m\]\w\[\033[00m\]> "
 
+if [ "$#" -eq 0 ]; then
+    command="/bin/bash -i"
+else
+    command="/usr/bin/bst $@"
+fi
+
 exec docker run --rm -i${is_tty:+ -t} \
                 --cap-add SYS_ADMIN \
                 --env PS1="$BST_HERE_PS1" \
@@ -68,4 +74,4 @@ exec docker run --rm -i${is_tty:+ -t} \
                 --volume "$PWD":/src \
                 --workdir /src \
                 buildstream/buildstream-fedora:latest \
-                "$@"
+                $command
diff --git a/doc/source/docker.rst b/doc/source/docker.rst
index 55e456d87..20dc6a9c1 100644
--- a/doc/source/docker.rst
+++ b/doc/source/docker.rst
@@ -21,18 +21,19 @@ Check if ``~/.local/bin`` appears in your PATH environment variable -- if it
 doesn't, you should
 `edit your ~/.profile so that it does <https://stackoverflow.com/questions/14637979/>`_.
 
-Once ``bst-here`` is available in your PATH, you just prefix every BuildStream
-command you need to run with ``bst-here`` so that it executes through the
-wrapper. The latest version of the buildstream-fedora Docker image is
-automatically pulled if needed. The contents of your working directory will be
-made available at ``/src`` inside the container.
+Once the script is available in your PATH, you can run ``bst-here`` to open a
+shell session inside a new container based off the latest version of the
+buildstream-fedora Docker image. The current working directory will be mounted
+inside the container at ``/src``.
 
-Two other volumes are set up by the ``bst-here`` script:
+You can also run individual BuildStream commands as ``bst-here COMMAND``. For
+example: ``bst-here show systems/my-system.bst``. Note that BuildStream won't
+be able to integrate with Bash tab-completion if you invoke it in this way.
+
+Two Docker volumes are set up by the ``bst-here`` script:
 
  * buildstream-cache -- mounted at ``~/.cache/buildstream``
  * buildstream-config -- mounted at ``~/.config/``
 
 These are necessary so that your BuildStream cache and configuration files
-persist between invocations of ``bst-here``. You can open a shell inside the
-container by running ``bst-here -t /bin/bash``, which is useful if for example
-you need to add something custom to ``~/.config/buildstream.conf``.
+persist between invocations of ``bst-here``.