start-container-docker.sh: Add "--task precommit"precommit

Configure container for precommit testing:
- use tcwg-build user instead of tcwg-buildslave;
- disable ssh agent forwarding;
- use scratch docker volume for $WORKSPACE instead of bind-mounting from host;
  -- use ++rsync_to and ++rsync_from options to transfer data to and from
     precommit container -- this is handled in docker-run.sh;
- mount everything else as read-only (e.g., ccache, snapshots-ref, etc.);
- translate absolute /home/* paths

Change-Id: I864174b3a3b3a89a8da15f52a8a0da7f0d948cb7

2 files changed, 48 insertions, 2 deletions

diff --git a/jenkins-helpers.sh b/jenkins-helpers.sh
index 5fffda0c..a6603b8c 100644
--- a/jenkins-helpers.sh
+++ b/jenkins-helpers.sh
@@ -720,7 +720,7 @@ print_memory_limit ()
     local memlimit="$4"
     local memory
     case "$task" in
-	build)
+	build|precommit)
 	    if [ "$memlimit" -lt "4000" ]; then
 		# Don't limit memory on machines with less than 4GB RAM.
 		memory="unlimited"
@@ -790,6 +790,14 @@ print_mounts ()
 	    bench|build)
 		echo "$WORKSPACE:$WORKSPACE"
 		;;
+	    precommit)
+		# Note the difference between "-v $WORKSPACE:$WORKSPACE" above
+		# and "-v $WORKSPACE" here.  In the above case $WORKSPACE is
+		# bind-mounted from the host; but in this case a scratch volume
+		# is created and mounted inside container.
+		echo "$WORKSPACE"
+		echo "$WORKSPACE/base-artifacts:$WORKSPACE/base-artifacts:ro"
+		;;
 	esac
     fi
 
@@ -829,12 +837,17 @@ print_mounts ()
 	    volume_id=$(print_docker_name "$prefix$suffix")
 
 	    local readonly=""
+	    if [ "$task" = "precommit" ]; then
+		readonly=":ro"
+	    fi
 	    echo "ccache-$volume_id:$HOME/.ccache$readonly"
 	    ;;
     esac
 
     case "$job" in
 	tcwg_bmk*)
+	    assert_with_msg "Precommit benchmarking requires more thought" \
+			    [ "$task" != "precommit" ]
 	    # Add scratch mount for tcwg-benchmark's $HOME.
 	    # tcwg_bmk-* jobs trigger tcwg-benchmark jenkins jobs, which
 	    # then ssh to the build container to compile benchmark objects
diff --git a/start-container-docker.sh b/start-container-docker.sh
index 93ff8543..a54965d6 100755
--- a/start-container-docker.sh
+++ b/start-container-docker.sh
@@ -126,7 +126,7 @@ do
 	--task)
 	    task=$2
 	    case "${task}" in
-	        build|bench|test) ;;
+	        build|precommit|bench|test) ;;
 		*) usage ;;
 	    esac
 	    shift 2
@@ -228,6 +228,29 @@ SSH="ssh -Snone -oForwardAgent=no"
 
 pwd_translate=(cat)
 
+# Configure container for precommit testing:
+# - use tcwg-build user instead of tcwg-buildslave;
+# - disable ssh agent forwarding;
+# - use scratch docker volume for $WORKSPACE instead of bind-mounting from host;
+#   -- use ++rsync_to and ++rsync_from options to transfer data to and from
+#      precommit container -- this is handled in docker-run.sh;
+# - mount everything else as read-only (e.g., ccache, snapshots-ref, etc.);
+# - translate absolute /home/* paths
+if [ "$task" = "precommit" ]; then
+    if [ "$newuser" = "" ]; then
+	newuser=tcwg-build
+    fi
+    if [ "$user" = "" ]; then
+	user="$newuser"
+    fi
+
+    if [ "${WORKSPACE+set}" = "set" ]; then
+	# Translate /home/tcwg-buildslave/* paths to /home/tcwg-build/* paths.
+	dst_workspace=$(echo "$WORKSPACE" | sed -e "s#^$HOME#/home/$user#")
+	pwd_translate=(sed -e "s#^$WORKSPACE#$dst_workspace#")
+    fi
+fi
+
 assert_with_msg "user and USER variables should not be set to the same value" \
 		[ x"$user" != x"$USER" ]
 
@@ -438,6 +461,16 @@ if [ "$user" != "" ]; then
 		git config --global --add safe.directory "$dir"
     done
 
+    if [ "$user" = "tcwg-build" ]; then
+	# FIXME: Hack -- use tcwg-buildslave's key while tcwg-build's
+	#        is unavailable.
+	$DOCKER exec "$session_id" cp \
+		/home/tcwg-buildslave/.ssh/authorized_keys \
+		/home/tcwg-build/.ssh/authorized_keys
+	$DOCKER exec "$session_id" chown $user \
+		/home/tcwg-build/.ssh/authorized_keys
+    fi
+
     # Below $user is used as a prefix for $session_host
     user="$user@"
 fi