<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Read/write master-capable backends</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PowerDNS manual" HREF="index.html"><LINK REL="UP" TITLE="Backend writers' guide" HREF="backend-writers-guide.html"><LINK REL="PREVIOUS" TITLE="Read/write slave-capable backends" HREF="rw-backends.html"><LINK REL="NEXT" TITLE="Compiling PowerDNS" HREF="compiling-powerdns.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PowerDNS manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="rw-backends.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Appendix C. Backend writers' guide</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="compiling-powerdns.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="MASTER-BACKENDS" >C.5. Read/write master-capable backends</A ></H1 ><P > In order to be a useful master for a domain, notifies must be sent out whenever a domain is changed. Periodically, PDNS queries backends for domains that may have changed, and sends out notifications for slave nameservers. </P ><P > In order to do so, PDNS calls the <CODE CLASS="FUNCTION" >getUpdatedMasters()</CODE > method. Like the <CODE CLASS="FUNCTION" >getUnfreshSlaveInfos()</CODE > function mentioned above, this should add changed domain names to the vector passed. </P ><P > The following excerpt from the DNSBackend shows the relevant functions: </P ><P > <PRE CLASS="PROGRAMLISTING" > class DNSBackend { public: /* ... */ virtual void getUpdatedMasters(vector<DomainInfo>* domains); virtual void setNotifed(int id, u_int32_t serial); /* ... */ } </PRE > </P ><P > These functions all have a default implementation that returns false - which explains that these methods can be omitted in simple backends. Furthermore, unlike with simple backends, a slave capable backend must make sure that the 'DNSBackend *db' field of the SOAData record is filled out correctly - it is used to determine which backend will house this zone. <P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT >void getUpdatedMasters(vector<DomainInfo>* domains)</DT ><DD ><P > When called, the backend should examine its list of master domains and add any changed ones to the DomainInfo vector </P ></DD ><DT >bool setNotified(int domain_id, u_int32_t serial)</DT ><DD ><P > Indicate that notifications have been queued for this domain and that it need not be considered 'updated' anymore </P ></DD ></DL ></DIV > </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="rw-backends.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="compiling-powerdns.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Read/write slave-capable backends</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="backend-writers-guide.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Compiling PowerDNS</TD ></TR ></TABLE ></DIV ></BODY ></HTML >