Supporting gobal smtp gateway usage

dicos/70_prometheus.xml

@@ -103,6 +103,9 @@
                 </family>
 
         <family name="alertes prometheus">
+			<variable name='alSMTPUseSys' type='oui/non' description="Utiliser la passerelle SMTP du système ?">
+				<value>non</value>
+			</variable>
             <variable name='alSMTPHost' type='string' description="Adresse du serveur SMTP pour l'envois des alertes"/>
             <variable name='alSMTPPort' type='string' description="Port d'écoute du serveur SMTP pour l'envois des alertes"/>
             <variable name='alFrom' type='string' description="Adresse d'origine des emails d'alerte"/>
@@ -211,6 +214,16 @@
             <param>['','service','severity']</param>
         </check>
 
+        <condition name='disabled_if_in' source='alSMTPUseSys'>
+            <param>oui</param>
+            <target type='variable'>alSMTPUser</target>
+            <target type='variable'>alSMTPPass</target>
+            <target type='variable'>alSMTPPort</target>
+            <target type='variable'>alSMTPTLS</target>
+			<target type='variable'>alSMTPHost</target>
+			<target type='variable'>alSMTPAuth</target>
+        </condition>
+
         <condition name='disabled_if_in' source='alSMTPAuth'>
             <param>non</param>
             <target type='variable'>alSMTPUser</target>

tmpl/alertmanager.yml

@@ -1,16 +1,28 @@
 global:
   # The smarthost and SMTP sender used for mail notifications.
+%if %%alSMTPUseSys ==  'oui'
+  %if %%tls_smtp == "non"
+  smtp_smarthost: '%%exim_relay_smtp:25'
+  %elif %%tls_smtp == "port 25"
+  smtp_smarthost: '%%exim_relay_smtp:25'
+  smtp_require_tls: true
+  %else
+  smtp_smarthost: '%%exim_relay_smtp:465'
+  smtp_require_tls: true
+  %end if
+%else
   smtp_smarthost: '%%alSMTPHost:%%alSMTPPort'
   smtp_from: '%%alFrom'
-%if %%getVar('alSMTPAuth','non') == 'oui'
+  %if %%getVar('alSMTPAuth','non') == 'oui'
   smtp_auth_username: '%%alSMTPUser'
   smtp_auth_password: 'alSMTPPass'
-%end if
+  %end if
 
-%if %%getVar('alSMTPTLS','non') == 'oui'
+  %if %%getVar('alSMTPTLS','non') == 'oui'
   smtp_require_tls: true
-%else
+  %else
   smtp_require_tls: false
+  %end if
 %end if
 
   # The auth token for Hipchat.