Add support for Azure DNS

Adding support for Azure DNS 
See https://docs.microsoft.com/en-us/azure/dns/

dnsapi/dns_azure.sh

@@ -0,0 +1,241 @@
+#!/usr/bin/env sh
+
+
+########  Public functions #####################
+
+ # Usage: add  _acme-challenge.www.domain.com   "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
+# Used to add txt record
+#
+# Ref: https://docs.microsoft.com/en-us/rest/api/dns/recordsets/createorupdate
+#
+dns_azure_add() 
+{ 
+   fulldomain=$1
+   txtvalue=$2
+  
+   AZUREDNS_SUBSCRIPTIONID="${AZUREDNS_SUBSCRIPTIONID:-$(_readaccountconf_mutable AZUREDNS_SUBSCRIPTIONID)}"
+   AZUREDNS_TENANTID="${AZUREDNS_TENANTID:-$(_readaccountconf_mutable AZUREDNS_TENANTID)}"
+   AZUREDNS_APPID="${AZUREDNS_APPID:-$(_readaccountconf_mutable AZUREDNS_APPID)}"
+   AZUREDNS_CLIENTSECRET="${AZUREDNS_CLIENTSECRET:-$(_readaccountconf_mutable AZUREDNS_CLIENTSECRET)}"
+  
+   if [ -z "$AZUREDNS_SUBSCRIPTIONID" ]; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""   
+	 _err "You didn't specify the Azure Subscription ID "
+     return 1
+   fi
+
+   if [ -z "$AZUREDNS_TENANTID" ] ; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""  
+	 _err "You didn't specify then Azure Tenant ID "
+     return 1
+   fi
+
+   if  [ -z "$AZUREDNS_APPID" ] ; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""   
+	 _err "You didn't specify the Azure App ID"
+     return 1
+   fi
+
+   if [ -z "$AZUREDNS_CLIENTSECRET" ]; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""  
+	 _err "You didn't specify the Azure Client Secret"
+     return 1
+   fi
+   #save account details to account conf file.
+   _saveaccountconf_mutable AZUREDNS_SUBSCRIPTIONID "$AZUREDNS_SUBSCRIPTIONID"
+   _saveaccountconf_mutable AZUREDNS_TENANTID "$AZUREDNS_TENANTID"
+   _saveaccountconf_mutable AZUREDNS_APPID "$AZUREDNS_APPID"
+   _saveaccountconf_mutable AZUREDNS_CLIENTSECRET "$AZUREDNS_CLIENTSECRET"
+
+
+   accesstoken=$(_azure_getaccess_token "$AZUREDNS_TENANTID" "$AZUREDNS_APPID" "$AZUREDNS_CLIENTSECRET")
+  
+   if ! _get_root "$fulldomain"  "$AZUREDNS_SUBSCRIPTIONID" "$accesstoken"; then
+    _err "invalid domain"
+    return 1
+   fi
+   _debug _domain_id "$_domain_id"
+   _debug _sub_domain "$_sub_domain"
+   _debug _domain "$_domain"  
+  
+   acmeRecordURI="https://management.azure.com$(printf '%s' $_domain_id |sed 's/\\//g')/TXT/$_sub_domain?api-version=2017-09-01"
+   _debug $acmeRecordURI
+   body="{\"properties\": {\"TTL\": 3600, \"TXTRecords\": [{\"value\": [\"$txtvalue\"]}]}}"
+   _azure_rest PUT "$acmeRecordURI" "$body" "$accesstoken"
+   _debug $response
+}
+
+# Usage: fulldomain txtvalue
+# Used to remove the txt record after validation
+#
+# Ref: https://docs.microsoft.com/en-us/rest/api/dns/recordsets/delete
+#
+dns_azure_rm() 
+{ 
+   fulldomain=$1
+   txtvalue=$2
+  
+   AZUREDNS_SUBSCRIPTIONID="${AZUREDNS_SUBSCRIPTIONID:-$(_readaccountconf_mutable AZUREDNS_SUBSCRIPTIONID)}"
+   AZUREDNS_TENANTID="${AZUREDNS_TENANTID:-$(_readaccountconf_mutable AZUREDNS_TENANTID)}"
+   AZUREDNS_APPID="${AZUREDNS_APPID:-$(_readaccountconf_mutable AZUREDNS_APPID)}"
+   AZUREDNS_CLIENTSECRET="${AZUREDNS_CLIENTSECRET:-$(_readaccountconf_mutable AZUREDNS_CLIENTSECRET)}"
+  
+   if [ -z "$AZUREDNS_SUBSCRIPTIONID" ]; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""   
+	 _err "You didn't specify the Azure Subscription ID "
+     return 1
+   fi
+
+   if [ -z "$AZUREDNS_TENANTID" ] ; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""  
+	 _err "You didn't specify the Azure Tenant ID "
+     return 1
+   fi
+
+   if  [ -z "$AZUREDNS_APPID" ]  ;then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""   
+	 _err "You didn't specify the Azure App ID"
+     return 1
+   fi
+
+   if [ -z "$AZUREDNS_CLIENTSECRET" ]; then
+     AZUREDNS_SUBSCRIPTIONID=""
+     AZUREDNS_TENANTID=""
+     AZUREDNS_APPID="" 
+     AZUREDNS_CLIENTSECRET=""  
+	 _err "You didn't specify Azure Client Secret"
+     return 1
+   fi
+
+   accesstoken=$(_azure_getaccess_token "$AZUREDNS_TENANTID" "$AZUREDNS_APPID" "$AZUREDNS_CLIENTSECRET")
+  
+   if ! _get_root "$fulldomain"  "$AZUREDNS_SUBSCRIPTIONID" "$accesstoken"; then
+    _err "invalid domain"
+    return 1
+   fi
+   _debug _domain_id "$_domain_id"
+   _debug _sub_domain "$_sub_domain"
+   _debug _domain "$_domain"  
+  
+   acmeRecordURI="https://management.azure.com$(printf '%s' $_domain_id |sed 's/\\//g')/TXT/$_sub_domain?api-version=2017-09-01"
+   _debug $acmeRecordURI
+   body="{\"properties\": {\"TTL\": 3600, \"TXTRecords\": [{\"value\": [\"$txtvalue\"]}]}}"
+   _azure_rest DELETE "$acmeRecordURI" "" "$accesstoken"
+   _debug $response
+}
+
+###################  Private functions below ##################################
+
+_azure_rest() {
+   m=$1
+   ep="$2"
+   data="$3"
+   accesstoken="$4"
+ 
+   _debug "$ep"
+
+   export _H1="authorization: Bearer $accesstoken"
+   export _H2="accept: application/json"
+   export _H3="Content-Type: application/json"
+   _H1="authorization: Bearer $accesstoken"
+   _H2="accept: application/json"
+   _H3="Content-Type: application/json"
+
+   if [ "$m" != "GET" ]; then
+    _debug data "$data"
+    response="$(_post "$data" "$ep" "" "$m")"
+   else
+    response="$(_get "$ep")"
+   fi
+   _debug2 response "$response"
+   if [ "$?" != "0" ]; then
+    _err "error $ep"
+    return 1
+   fi
+   return 0
+}
+
+## Ref: https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-protocols-oauth-service-to-service#request-an-access-token
+_azure_getaccess_token() {
+   TENANTID=$1
+   clientID=$2
+   clientSecret=$3
+  
+   export _H1="accept: application/json"
+   export _H2="Content-Type: application/x-www-form-urlencoded"
+   export _H3=""
+  
+   body="resource=$(printf "%s" 'https://management.core.windows.net/'| _url_encode)&client_id=$(printf "%s" $clientID | _url_encode)&client_secret=$(printf "%s" $clientSecret| _url_encode)&grant_type=client_credentials"
+   _debug data "$body"
+   response="$(_post "$body" "https://login.windows.net/$TENANTID/oauth2/token" "" "POST" )"
+   accesstoken=$(printf "%s\n" "$response" | _egrep_o "\"access_token\":\"[^\"]*\"" | head -n 1 | cut -d : -f 2 | tr -d \")
+  
+   if [ "$?" != "0" ]; then
+     _err "error $response"
+     return 1
+   fi
+   printf $accesstoken
+   _debug2 response "$response"
+   return 0
+}
+
+_get_root() {
+   domain=$1
+   subscriptionId=$2
+   accesstoken=$3
+   i=2
+   p=1
+
+   ## Ref: https://docs.microsoft.com/en-us/rest/api/dns/zones/list
+   ## returns up to 100 zones in one response therefore handling more results is not not implemented 
+   ## (ZoneListResult with  continuation token for the next page of results)
+   ## Per https://docs.microsoft.com/en-us/azure/azure-subscription-service-limits#dns-limits you are limited to 100 Zone/subscriptions anyways 
+   ##
+   _azure_rest GET "https://management.azure.com/subscriptions/$subscriptionId/providers/Microsoft.Network/dnszones?api-version=2017-09-01" "" $accesstoken 
+
+   # Find matching domain name is Json response
+   while true; do
+      h=$(printf "%s" "$domain" | cut -d . -f $i-100)
+      _debug2 "Checking domain: $h"
+      if [ -z "$h" ]; then
+        #not valid
+        _err "Invalid domain"
+        return 1
+      fi
+
+    if _contains "$response" "\"name\":\"$h\"" >/dev/null; then
+      _domain_id=$(printf "%s\n" "$response" | _egrep_o "\[.\"id\":\"[^\"]*\"" | head -n 1 | cut -d : -f 2 | tr -d \")
+      if [ "$_domain_id" ]; then
+        _sub_domain=$(printf "%s" "$domain" | cut -d . -f 1-$p)
+        _domain=$h
+        return 0
+      fi
+      return 1
+      fi
+      p=$i
+      i=$(_math "$i" + 1)
+   done
+   return 1
+}
+