deploy: Use Docker contexts.

Use Docker contexts in the deploy script and the Compose plugin to
deploy (instead of forwarding sockets over SSH).

deploy

 #!/bin/sh
 set -eu
 
-_docker_compose() {
-    docker-compose "$@" 2>&1 | sed '/^  File /,+1d'
-}
-
 _check() {
-    containers="$(until _docker_compose ps -q; do true; done)"
+    host="$1"
+    containers="$(until docker --context "$host" compose ps -q; do true; done)"
     # shellcheck disable=SC2086
-    docker container inspect --format '{{ .State.Health.Status }}' $containers | grep -v '^healthy$'
+    docker --context "$host" container inspect --format '{{ .State.Health.Status }}' $containers | grep -v '^healthy$'
 }
 
 _deploy() {
     host="$1"
-    printf '\n\e[1;94m=== %s ====\e[0m\n\n' "Deploying to $host" >&2
-    localsocket="$HOME/.ssh/docker_$host.sock"
-    forward "$host" "$localsocket:/var/run/docker.sock"
-    export DOCKER_HOST="unix://$localsocket"
-    export RUNNER_NAME="$host"
-    until _docker_compose up --detach --remove-orphans ; do true; done
-    # shellcheck disable=SC2034
+    printf '\n\e[1;94m=== %s ====\e[0m\n\n' "Deploying to ${host}.shore.co.il" >&2
+    export RUNNER_NAME="${host}.shore.co.il"
+    until docker --context "$host" compose up --detach --remove-orphans ; do true; done
     for i in $(seq 12)
     do
-        # shellcheck disable=SC2046
-        _check || break
+        _check "$host" || break
         sleep 10
     done
-    # shellcheck disable=SC2046
-    ! _check
-    unset DOCKER_HOST
+    # shellcheck disable=SC2251
+    ! _check "$host"
     unset RUNNER_NAME
 }
 
@@ -48,15 +39,15 @@ do
     case "$i" in
         ns4) export REGISTER_RUN_UNTAGGED="true"
             export BUILDS='/builds'
-            _deploy ns4.shore.co.il
+            _deploy ns4
             ;;
         kodi) export REGISTER_RUN_UNTAGGED="false"
             unset BUILDS
-            _deploy kodi.shore.co.il
+            _deploy kodi
             ;;
         host01) export REGISTER_RUN_UNTAGGED="false"
             unset BUILDS
-            _deploy host01.shore.co.il
+            _deploy host01
             ;;
         all) "$0" ns4 host01 kodi ;;
         *) echo 'Unknown host.' >&2; exit 1;;