Introduce helper script for easier docker API questioning

docker-api.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+url=$1
+shift
+
+if (( $# )); then
+    url="$url?"
+fi
+
+while (( $# > 1 )); do
+    key=$1
+    value=$2
+    shift 2
+    url="${url}$key=$(echo $value | jq -s -R -r @uri)&"
+done
+
+if (( $# )); then
+    url="${url}$1"
+fi
+
+curl -s --fail-with-body --unix-socket /var/run/docker.sock "http://v1.45$url"

services.sh

@@ -3,12 +3,9 @@
 source ./config.sh
 source ./logger.sh
 
-sock=/var/run/docker.sock
-url=http://v1.45
-
 LABEL="swarm-health-alerter.port"
 
-curl -s --fail-with-body --unix-socket $sock $url/services -o /tmp/services
+./docker-api.sh /services > /tmp/services
 if [ $? -ne 0 ]; then
     log_error "$(jq -r .message /tmp/services 2>/dev/null || cat /tmp/services)"
     exit 1