puppet: Only run deliver_scheduled_messages and _emails on one server.

`deliver_scheduled_emails` and `deliver_scheduled_messages` use the
`ScheduledEmail` and `ScheduledMessage` tables as a queue,
effectively, pulling values off of them.  As noted in their comments,
this is not safe to run on multiple hosts at once.  As such, split out
the supervisor files for them.

puppet/zulip/manifests/app_frontend_once.pp

@@ -2,6 +2,23 @@
 # in a cluster.
 
 class zulip::app_frontend_once {
+  $proxy_host = zulipconf('http_proxy', 'host', '')
+  $proxy_port = zulipconf('http_proxy', 'port', '')
+  if $proxy_host != '' and $proxy_port != '' {
+    $proxy = "http://${proxy_host}:${proxy_port}"
+  } else {
+    $proxy = ''
+  }
+  file { "${zulip::common::supervisor_conf_dir}/zulip-once.conf":
+    ensure  => file,
+    require => [Package[supervisor], Exec['stage_updated_sharding']],
+    owner   => 'root',
+    group   => 'root',
+    mode    => '0644',
+    content => template('zulip/supervisor/zulip-once.conf.template.erb'),
+    notify  => Service[$zulip::common::supervisor_service],
+  }
+
   file { '/etc/cron.d/send-digest-emails':
     ensure => file,
     owner  => 'root',

puppet/zulip/templates/supervisor/zulip-once.conf.template.erb

@@ -0,0 +1,29 @@
+[program:zulip_deliver_scheduled_emails]
+command=nice -n15 /home/zulip/deployments/current/manage.py deliver_scheduled_emails
+environment=HTTP_proxy="<%= @proxy %>",HTTPS_proxy="<%= @proxy %>"
+priority=350                   ; the relative start priority (default 999)
+autostart=true                 ; start at supervisord start (default: true)
+autorestart=true               ; whether/when to restart (default: unexpected)
+stopsignal=TERM                ; signal used to kill process (default TERM)
+topwaitsecs=30                ; max num secs to wait b4 SIGKILL (default 10)
+user=zulip                    ; setuid to this UNIX account to run the program
+redirect_stderr=true           ; redirect proc stderr to stdout (default false)
+stdout_logfile=/var/log/zulip/events_deliver_scheduled_emails.log         ; stdout log path, NONE for none; default AUTO
+stdout_logfile_maxbytes=20MB   ; max # logfile bytes b4 rotation (default 50MB)
+stdout_logfile_backups=3     ; # of stdout logfile backups (default 10)
+directory=/home/zulip/deployments/current/
+
+[program:zulip_deliver_scheduled_messages]
+command=nice -n15 /home/zulip/deployments/current/manage.py deliver_scheduled_messages
+environment=HTTP_proxy="<%= @proxy %>",HTTPS_proxy="<%= @proxy %>"
+priority=350                   ; the relative start priority (default 999)
+autostart=true                 ; start at supervisord start (default: true)
+autorestart=true               ; whether/when to restart (default: unexpected)
+stopsignal=TERM                ; signal used to kill process (default TERM)
+topwaitsecs=30                ; max num secs to wait b4 SIGKILL (default 10)
+user=zulip                    ; setuid to this UNIX account to run the program
+redirect_stderr=true           ; redirect proc stderr to stdout (default false)
+stdout_logfile=/var/log/zulip/events_scheduled_message_deliverer.log         ; stdout log path, NONE for none; default AUTO
+stdout_logfile_maxbytes=20MB   ; max # logfile bytes b4 rotation (default 50MB)
+stdout_logfile_backups=3     ; # of stdout logfile backups (default 10)
+directory=/home/zulip/deployments/current/

puppet/zulip/templates/supervisor/zulip.conf.template.erb

@@ -94,36 +94,6 @@ stopasgroup=true              ; Without this, we leak processes every restart
 killasgroup=true              ; Without this, we leak processes every restart
 <% end %>
 
-[program:zulip_deliver_scheduled_emails]
-command=nice -n15 /home/zulip/deployments/current/manage.py deliver_scheduled_emails
-environment=HTTP_proxy="<%= @proxy %>",HTTPS_proxy="<%= @proxy %>"
-priority=350                   ; the relative start priority (default 999)
-autostart=true                 ; start at supervisord start (default: true)
-autorestart=true               ; whether/when to restart (default: unexpected)
-stopsignal=TERM                ; signal used to kill process (default TERM)
-topwaitsecs=30                ; max num secs to wait b4 SIGKILL (default 10)
-user=zulip                    ; setuid to this UNIX account to run the program
-redirect_stderr=true           ; redirect proc stderr to stdout (default false)
-stdout_logfile=/var/log/zulip/events_deliver_scheduled_emails.log         ; stdout log path, NONE for none; default AUTO
-stdout_logfile_maxbytes=20MB   ; max # logfile bytes b4 rotation (default 50MB)
-stdout_logfile_backups=3     ; # of stdout logfile backups (default 10)
-directory=/home/zulip/deployments/current/
-
-[program:zulip_deliver_scheduled_messages]
-command=nice -n15 /home/zulip/deployments/current/manage.py deliver_scheduled_messages
-environment=HTTP_proxy="<%= @proxy %>",HTTPS_proxy="<%= @proxy %>"
-priority=350                   ; the relative start priority (default 999)
-autostart=true                 ; start at supervisord start (default: true)
-autorestart=true               ; whether/when to restart (default: unexpected)
-stopsignal=TERM                ; signal used to kill process (default TERM)
-topwaitsecs=30                ; max num secs to wait b4 SIGKILL (default 10)
-user=zulip                    ; setuid to this UNIX account to run the program
-redirect_stderr=true           ; redirect proc stderr to stdout (default false)
-stdout_logfile=/var/log/zulip/events_scheduled_message_deliverer.log         ; stdout log path, NONE for none; default AUTO
-stdout_logfile_maxbytes=20MB   ; max # logfile bytes b4 rotation (default 50MB)
-stdout_logfile_backups=3     ; # of stdout logfile backups (default 10)
-directory=/home/zulip/deployments/current/
-
 ; The below sample group section shows all possible group values,
 ; create one or more 'real' group: sections to create "heterogeneous"
 ; process groups.