Support dynamic configuration update of named

An additional file contrail-named-base.conf will contain the base named configurtion
such as options stanza, key stanza, controls stanza and logging stanza.

All configs generated due to vdns configuration resulting in view stanza will be written
to contrail-named.conf

Before sending "reconfig" command to named, both the files will be merged
into contrail-named.conf

The above gives flexibility to user to update and apply changes without restarting
the dns daemon which generated the contrail-named.conf

An additional helper script(applynamedconfig.py) will merge the files and apply the
config(contrail-named-base.conf) to named daemon.

Change-Id: If6089189a1104f648d8d7d3f638c58f9883deb50
Closes-Bug:1605341

src/dns/SConscript

@@ -65,6 +65,8 @@ doc_files += env.SandeshGenDoc('bind/bind.sandesh')
 env.Alias('install', env.Install(env['INSTALL_BIN'], contrail_dns))
 env.Alias('install', env.Install(env['INSTALL_CONF'] + '/dns', 'contrail-dns.conf'))
 env.Alias('install', env.Install(env['INSTALL_CONF'] + 
+    '/dns', 'applynamedconfig.py'))
+env.Alias('install', env.Install(env['INSTALL_CONF'] +
     '/supervisord_control_files/', 'contrail-dns.ini'))
 env.Alias('install', env.Install(env['INSTALL_CONF'] + 
     '/supervisord_control_files/', 'contrail-named.ini'))

src/dns/applynamedconfig.py

@@ -0,0 +1,144 @@
+#
+# Copyright (c) 2016 Juniper Networks, Inc. All rights reserved.
+#
+
+"""
+This helper script is used to dynamically update configs to named.
+o For backward compatibility we read the named configurable
+   params from contrail-dns.conf and build contrail-named-base.conf
+o Alternatively user can create/update contrail-name-base.conf
+   for configuring named params
+o contrail-named.conf will be generated by dnsd which will
+   contain views/zones stanzas
+o contrail-named-base.conf will be merged with contrail-named.conf
+   by the script and config applied to named
+"""
+
+import sys
+import os
+import subprocess
+import ConfigParser
+
+def parse_contrail_dns_conf():
+
+    named_defaults = {
+        'named_config_file': 'DEFAULT....contrail-named.conf',
+        'named_config_directory': '/etc/contrail/dns',
+        'named_log_file': 'DEFAULT.../var/log/contrail/contrail-named.log',
+        'rndc_config_file': 'contrail-rndc.conf',
+        'rndc_secret': 'xvysmOR8lnUQRBcunkC6vg==',
+        'named_max_cache_size': '32M',
+        'named_max_retransmissions': '12',
+        'named_retransmission_interval': '1000',
+    }
+
+    # remove preceeding spaces from contrail-dns.conf
+    # and save it in contrail-dns-temp.conf
+    subprocess.call(["sed -e 's/^[ \t]*//g' < /etc/contrail/contrail-dns.conf \
+                                            > /etc/contrail/dns/contrail-dns-temp.conf"], shell=True)
+    # remove comments preceeding with #
+    subprocess.call(["sed -i 's/[;#].*$//g' /etc/contrail/dns/contrail-dns-temp.conf"], shell=True)
+
+    # parse contrail-dns.conf
+    dns_config = ConfigParser.SafeConfigParser()
+    dns_config.read('/etc/contrail/dns/contrail-dns-temp.conf')
+
+    # remove the temp file
+    os.remove("/etc/contrail/dns/contrail-dns-temp.conf")
+
+    # update defaults
+    named_defaults.update(dict(dns_config.items("DEFAULT")))
+
+    # create contrail-named-base.conf
+    file_named_base_conf=open('/etc/contrail/dns/contrail-named-base.conf', 'w+')
+
+    # build contrail-named-base.conf
+
+    # build options {} stanza
+    file_named_base_conf.write('options {\n')
+    file_named_base_conf.write('    directory "'+ named_defaults['named_config_directory'] + '";\n')
+    file_named_base_conf.write('    managed-keys-directory "'+ named_defaults['named_config_directory'] + '";\n')
+    file_named_base_conf.write('    empty-zones-enable no;\n')
+    file_named_base_conf.write('    pid-file "/etc/contrail/dns/contrail-named.pid";\n')
+    file_named_base_conf.write('    session-keyfile "/etc/contrail/dns/session.key";\n')
+    file_named_base_conf.write('    listen-on port 53 { any; };\n')
+    file_named_base_conf.write('    allow-query { any; };\n')
+    file_named_base_conf.write('    allow-recursion { any; };\n')
+    file_named_base_conf.write('    allow-query-cache { any; };\n')
+    file_named_base_conf.write('    max-cache-size '+ named_defaults['named_max_cache_size'] + ';\n')
+    file_named_base_conf.write('};\n\n')
+
+    # build rndc-key {} stanza
+    file_named_base_conf.write('key "rndc-key" {\n')
+    file_named_base_conf.write('   algorithm hmac-md5;\n')
+    file_named_base_conf.write('   secret "' + named_defaults['rndc_secret'] + '";\n')
+    file_named_base_conf.write('};\n\n')
+
+    #build controls {} stanza
+    file_named_base_conf.write('controls {\n')
+    file_named_base_conf.write('    inet 127.0.0.1 port 8094 \n')
+    file_named_base_conf.write('    allow { 127.0.0.1; }  keys { "rndc-key"; };\n')
+    file_named_base_conf.write('};\n\n')
+
+    #build logging {} stanza
+    file_named_base_conf.write('logging {\n')
+    file_named_base_conf.write('    channel debug_log {\n')
+    file_named_base_conf.write('        file "'+ named_defaults['named_log_file'] + '" versions 5 size 5m;\n')
+    file_named_base_conf.write('        severity debug;\n')
+    file_named_base_conf.write('        print-time yes;\n')
+    file_named_base_conf.write('        print-severity yes;\n')
+    file_named_base_conf.write('        print-category yes;\n')
+    file_named_base_conf.write('    };\n')
+    file_named_base_conf.write('    category default {\n')
+    file_named_base_conf.write('        debug_log;\n')
+    file_named_base_conf.write('    };\n')
+    file_named_base_conf.write('    category queries {\n')
+    file_named_base_conf.write('        debug_log;\n')
+    file_named_base_conf.write('    };\n')
+    file_named_base_conf.write('};\n\n')
+
+    file_named_base_conf.close()
+
+# end parse_contrail_dns_conf
+
+
+def main():
+    if not os.path.exists('/etc/contrail/dns/contrail-named-base.conf'):
+        # parse contrail-dns.conf and build contrail-named-base.conf
+        parse_contrail_dns_conf()
+
+    # open contrail-named-base.conf and read the base configs
+    file1 = open('/etc/contrail/dns/contrail-named-base.conf', 'r')
+    file1_lines = file1.readlines()
+    file1.close()
+
+    # open contrail-named.conf and remove configurable stanzas
+    # options{} key{} controls{} logging {}
+    count = 0
+    file2 = open('/etc/contrail/dns/contrail-named.conf', 'r')
+    lines = file2.readlines()
+    for i, line in enumerate(lines[:]):
+        if line.startswith('view'):
+            break
+        else:
+           count = count + 1
+    file2.close()
+
+    # delete all lines before the view stanza {}
+    del lines[1:count]
+
+    # open contrail-named.conf
+    file3 = open('/etc/contrail/dns/contrail-named.conf', 'w')
+    file3.truncate()
+    file3.write("/* Build from contrail-named-base.conf */\n")
+    file3.writelines(file1_lines)
+    file3.write("/* Build from contrail-named.conf */\n")
+    file3.writelines(lines)
+    file3.close()
+
+    # apply config
+    os.system('/usr/bin/contrail-rndc -c /etc/contrail/dns/contrail-rndc.conf reconfig')
+#end main
+
+if __name__ == "__main__":
+    main()

src/dns/bind/named_config.cc

@@ -130,25 +130,39 @@ void NamedConfig::DelZone(const Subnet &subnet, const VirtualDnsConfig *vdns) {
 void NamedConfig::UpdateNamedConf(const VirtualDnsConfig *updated_vdns) {
     CreateNamedConf(updated_vdns);
     sync();
-    // rndc_reconfig();
-    // TODO: convert this to a call to rndc library
-    std::stringstream str;
-    str << "/usr/bin/contrail-rndc -c " << rndc_config_file_ << " -p ";
-    str << ContrailPorts::DnsRndc();
-    str << " reconfig";
-    int res = system(str.str().c_str());
-    if (res) {
-        LOG(WARN, "/usr/bin/contrail-rndc command failed");
+
+    ifstream pyscript("/etc/contrail/dns/applynamedconfig.py");
+    if (!pyscript.good()) {
+        std::stringstream str;
+        str << "/usr/bin/contrail-rndc -c " << rndc_config_file_ << " -p ";
+        str << ContrailPorts::DnsRndc();
+        str << " reconfig";
+        int res = system(str.str().c_str());
+        if (res) {
+            LOG(WARN, "/usr/bin/contrail-rndc command failed");
+        }
+    } else {
+        std::stringstream str;
+        // execute the helper script to apply named config
+        str << "python /etc/contrail/dns/applynamedconfig.py";
+        int res = system(str.str().c_str());
+        if (res) {
+            LOG(ERROR, "Applying named configuration failed");
+        }
     }
 }
 
 void NamedConfig::CreateNamedConf(const VirtualDnsConfig *updated_vdns) {
      GetDefaultForwarders();
      file_.open(named_config_file_.c_str());
-
-     WriteOptionsConfig();
-     WriteRndcConfig();
-     WriteLoggingConfig();
+
+     ifstream pyscript("/etc/contrail/dns/applynamedconfig.py");
+     if (!pyscript.good()) {
+         WriteOptionsConfig();
+         WriteRndcConfig();
+         WriteLoggingConfig();
+     }
+
      WriteViewConfig(updated_vdns);
 
      file_.flush();