Add add-on duckDNS (#40)

Add add-on duckDNS

duckdns/Dockerfile

@@ -0,0 +1,14 @@
+FROM %%BASE_IMAGE%%
+
+# Add version
+ENV VERSION %%VERSION%%
+ENV LANG C.UTF-8
+
+# Setup base
+RUN apk add --no-cache jq curl
+
+# Copy data
+COPY run.sh /
+RUN chmod a+x /run.sh
+
+CMD [ "/run.sh" ]

duckdns/config.json

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+{
+  "name": "Duck DNS",
+  "version": "0.1",
+  "slug": "duckdns",
+  "description": "Free dynamic DNS hosted on Amazon VPC",
+  "url": "https://home-assistant.io/addons/duckdns/",
+  "startup": "before",
+  "boot": "auto",
+  "options": {
+    "token": null,
+    "domains": [null],
+    "seconds": 300
+  },
+  "schema": {
+    "token": "email",
+    "domain": ["str"],
+    "seconds": "int"
+  }
+}

duckdns/run.sh

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+#!/bin/bash
+set -e
+
+CONFIG_PATH=/data/options.json
+
+TOKEN=$(jq --raw-output ".token" $CONFIG_PATH)
+DOMAINS=$(jq --raw-output ".domains[]" $CONFIG_PATH)
+SECONDS=$(jq --raw-output ".seconds" $CONFIG_PATH)
+
+for line in $DOMAINS; do
+    if [ -z "$DOMAIN_ARG" ]; then
+        DOMAIN_ARG="$line"
+    else
+        DOMAIN_ARG="$DOMAIN_ARG,$line"
+    fi
+done
+
+#
+while true; do
+    curl -k "https://www.duckdns.org/update?domains=$DOMAIN_ARG&token=$TOKEN&ip="
+    sleep "$SECONDS"
+done