[master] Merge branch 'trac3804'

diff --cc doc/guide/logging.xml
index 1283906a56bdbf2f2456586700a7b131f84a6523,6e3218c878977f8c33cc2864299d226532d499ff..c965f96abf14c4a102568b8ac1ff31f489dddf21
--- 1/doc/guide/logging.xml
--- 2/doc/guide/logging.xml
+++ b/doc/guide/logging.xml
@@@ -174,15 -167,15 +174,21 @@@
            </listitem>
            <listitem>
              <simpara><command>kea-dhcp4.hooks</command> - this logger is used
-             during DHCPv4 hooks operation, i.e. anything related to user
-             libraries will be logged using this logger.</simpara>
+             to log messages related to management of hooks libraries, e.g.
+             registration and deregistration of the libraries.</simpara>
+           </listitem>
+           <listitem>
+             <simpara><command>kea-dhcp4.callouts</command> - this logger is used
+             to log messages pertaining to the callouts registration and execution
+             for the particular hook point.
+             </simpara>
            </listitem>
 +          <listitem>
 +            <simpara><command>kea-dhcp4.hosts</command> - this logger is used
 +            within the libdhcpsrv and it logs messages related to the management
 +            of the DHCPv4 host reservations, i.e. retrieval of the resevations
 +            and adding new reservations.</simpara>
 +          </listitem>
            <listitem>
              <simpara><command>kea-dhcp6</command> - this is the root logger for
              the DHCPv6 server. All components used by the DHCPv6 server inherit
@@@ -202,15 -195,15 +208,21 @@@
            </listitem>
            <listitem>
              <simpara><command>kea-dhcp6.hooks</command> - this logger is used
-             during DHCPv6 hooks operation, i.e. anything related to user
-             libraries will be logged using this logger.</simpara>
+             to log messages related to management of hooks libraries, e.g.
+             registration and deregistration of the libraries.</simpara>
+           </listitem>
+           <listitem>
+             <simpara><command>kea-dhcp6.callouts</command> - this logger is used
+             to log messages pertaining to the callouts registration and execution
+             for the particular hook point.
+             </simpara>
            </listitem>
 +          <listitem>
 +            <simpara><command>kea-dhcp6.hosts</command> - this logger is used
 +            within the libdhcpsrv and it logs messages related to the management
 +            of the DHCPv6 host reservations, i.e. retrieval of the resevations
 +            and adding new reservations.</simpara>
 +          </listitem>
            <listitem>
              <simpara><command>kea-dhcp-ddns</command> - this is the root logger for
              the kea-dhcp-ddns deamon. All components used by this deamon inherit

diff --cc src/lib/hooks/callout_manager.cc
Simple merge