enhance idle connections

dovecot/tasks/main.yml

@@ -21,6 +21,7 @@
     - { src: 'templates/conf.d/10-master.conf.j2', dest: '/etc/dovecot/conf.d/10-master.conf' }
     - { src: 'templates/conf.d/10-ssl.conf.j2', dest: '/etc/dovecot/conf.d/10-ssl.conf' }
     - { src: 'templates/conf.d/20-managesieve.conf.j2', dest: '/etc/dovecot/conf.d/20-managesieve.conf' }
+    - { src: 'templates/conf.d/20-imap.conf.j2', dest: '/etc/dovecot/conf.d/20-imap.conf' }
     - { src: 'templates/conf.d/20-lmtp.conf.j2', dest: '/etc/dovecot/conf.d/20-lmtp.conf' }
     - { src: 'templates/conf.d/90-sieve.conf.j2', dest: '/etc/dovecot/conf.d/90-sieve.conf' }
     - { src: 'templates/conf.d/auth-passwdfile.conf.ext.j2', dest: '/etc/dovecot/conf.d/auth-passwdfile.conf.ext' }

dovecot/templates/conf.d/20-imap.conf.j2

+##
+## IMAP specific settings
+##
+
+# If nothing happens for this long while client is IDLEing, move the connection
+# to imap-hibernate process and close the old imap process. This saves memory,
+# because connections use very little memory in imap-hibernate process. The
+# downside is that recreating the imap process back uses some resources.
+#imap_hibernate_timeout = 0
+
+# Maximum IMAP command line length. Some clients generate very long command
+# lines with huge mailboxes, so you may need to raise this if you get
+# "Too long argument" or "IMAP command line too large" errors often.
+#imap_max_line_length = 64k
+
+# IMAP logout format string:
+#  %i - total number of bytes read from client
+#  %o - total number of bytes sent to client
+#  %{fetch_hdr_count} - Number of mails with mail header data sent to client
+#  %{fetch_hdr_bytes} - Number of bytes with mail header data sent to client
+#  %{fetch_body_count} - Number of mails with mail body data sent to client
+#  %{fetch_body_bytes} - Number of bytes with mail body data sent to client
+#  %{deleted} - Number of mails where client added \Deleted flag
+#  %{expunged} - Number of mails that client expunged
+#  %{trashed} - Number of mails that client copied/moved to the
+#               special_use=\Trash mailbox.
+#imap_logout_format = in=%i out=%o
+
+# Override the IMAP CAPABILITY response. If the value begins with '+',
+# add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
+#imap_capability = 
+
+# How long to wait between "OK Still here" notifications when client is
+# IDLEing.
+#imap_idle_notify_interval = 2 mins
+imap_idle_notify_interval = 29 mins
+
+# ID field names and values to send to clients. Using * as the value makes
+# Dovecot use the default value. The following fields have default values
+# currently: name, version, os, os-version, support-url, support-email.
+#imap_id_send = 
+
+# ID fields sent by client to log. * means everything.
+#imap_id_log =
+
+# Workarounds for various client bugs:
+#   delay-newmail:
+#     Send EXISTS/RECENT new mail notifications only when replying to NOOP
+#     and CHECK commands. Some clients ignore them otherwise, for example OSX
+#     Mail (<v2.1). Outlook Express breaks more badly though, without this it
+#     may show user "Message no longer in server" errors. Note that OE6 still
+#     breaks even with this workaround if synchronization is set to
+#     "Headers Only".
+#   tb-extra-mailbox-sep:
+#     Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
+#     adds extra '/' suffixes to mailbox names. This option causes Dovecot to
+#     ignore the extra '/' instead of treating it as invalid mailbox name.
+#   tb-lsub-flags:
+#     Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
+#     This makes Thunderbird realize they aren't selectable and show them
+#     greyed out, instead of only later giving "not selectable" popup error.
+#
+# The list is space-separated.
+#imap_client_workarounds = 
+
+# Host allowed in URLAUTH URLs sent by client. "*" allows all.
+#imap_urlauth_host =
+
+protocol imap {
+  # Space separated list of plugins to load (default is global mail_plugins).
+  #mail_plugins = $mail_plugins
+
+  # Maximum number of IMAP connections allowed for a user from each IP address.
+  # NOTE: The username is compared case-sensitively.
+  #mail_max_userip_connections = 10
+  mail_max_userip_connections = 40
+}