first version of notification to Home Assistant (#213)

* first working version of notification to Home Assistant

* add documentation links

* update readme for notify_HA

notify_templates/notify_HA.sh

@@ -0,0 +1,31 @@
+### DISCLAIMER: This is a third party addition to dockcheck - best effort testing.
+NOTIFY_HA_VERSION="v0.1"
+#
+# This is an integration that makes it possible to send notifications via Home Assistant (https://www.home-assistant.io/integrations/notify/)
+# You need to generate a long-lived access token in Home Sssistant to be used here (https://developers.home-assistant.io/docs/auth_api/#long-lived-access-token)
+# Leave (or place) this file in the "notify_templates" subdirectory within the same directory as the main dockcheck.sh script.
+# If you instead wish make your own modifications, make a copy in the same directory as the main dockcheck.sh script.
+# Do not modify this file directly within the "notify_templates" subdirectory. Set HA_ENTITY, HA_URL and HA_TOKEN in your dockcheck.config file.
+
+if [[ -z "${HA_ENTITY:-}" ]] || [[ -z "${HA_URL:-}" ]] || [[ -z "${HA_TOKEN:-}" ]]; then
+  printf "Home Assistant notification channel enabled, but required configuration variables are missing. Home assistant notifications will not be sent.\n"
+
+  remove_channel HA
+fi
+
+trigger_HA_notification() {
+  AccessToken="${HA_TOKEN}"
+  Url="${HA_URL}/api/services/notify/${HA_ENTITY}"
+  JsonData=$( "$jqbin" -n \
+              --arg body "$MessageBody" \
+              '{"title": "dockcheck update", "message": $body}' )
+
+  curl -S -o /dev/null ${CurlArgs} \
+    -H "Authorization: Bearer $AccessToken" \
+    -H "Content-Type: application/json" \
+    -d "$JsonData" -X POST $Url
+
+  if [[ $? -gt 0 ]]; then
+    NotifyError=true
+  fi
+}