dssh: add login-by-name

diff --git a/dssh b/dssh
index c67976e..a00ca4d 100755 (executable)
--- a/dssh
+++ b/dssh
@@ -9,7 +9,50 @@ die() {
     exit 1
 }
 
-CONTAINER=${1}
-[ "x${CONTAINER}" == "x" ] && die "You must supply a container name as the first argument."
-shift
-docker exec -it "${CONTAINER}" bash "${@}"
+usage() {
+    cat <<EOF
+dssh: log in to a docker node
+
+usage: dssh: [options]
+
+options:
+-h:           show this help message.
+-i [ID]:      ssh into a docker node with this container ID
+-n [name]:    ssh into a docker node with this name
+EOF
+}
+
+DOCKER_IMAGE_ID=""
+DOCKER_IMAGE_NAME=""
+while getopts  "hi:n:" flag; do
+    case $flag in
+    h) usage; exit 0;;
+    i) DOCKER_IMAGE_ID=${OPTARG};;
+    n) DOCKER_IMAGE_NAME=${OPTARG};;
+    *) echo "getopts error"
+        echo
+        usage
+        exit 1;;
+    esac
+done
+
+which docker &>/dev/null || die "docker must be on the PATH."
+
+if [ "x${DOCKER_IMAGE_NAME}" == "x" ]; then
+    if [ "x${DOCKER_IMAGE_ID}" == "x" ]; then
+        usage
+        exit 1
+    fi
+else
+    if [ "x${DOCKER_IMAGE_ID}" == "x" ]; then
+        :
+    else
+        echo "You must not supply both an ID and a name."
+        exit 1
+    fi
+    DOCKER_IMAGE_ID=$(docker ps -f name=${DOCKER_IMAGE_NAME} -q)
+    [ "x${DOCKER_IMAGE_ID}" == "x" ] && \
+        die "failed to find a docker image named ${DOCKER_IMAGE_NAME}"
+fi
+
+docker exec -it "${DOCKER_IMAGE_ID}" /bin/bash