On Mon, 2008-03-24 at 15:46 -0700, Ankur Shah wrote: > Hi Oleg, > > Thanks for the response. The server that i am running (acting as a client in > this particular case) is working with multiple servers (hosting different > webservices) with each having a primary and a failover pair. From this > perspective the thought was that rather than having different classes (all > having their own business logic around invoking the service) handle the > connection failed attempt, somehow have some central code that attempts to > connect to the primary and fails over to the backup. I also wanted to make > sure that in case of a connection failure with primary, a new pool is > established against the backup server. > > From this perspective, an after thought that I had was this. I was going to > extend the MultiThreadedHttpConnectionManager and have a failover capable > connection manager. In there, i was thinking about exposing a method (or a > new constructor) that allows backup host and ports to be added. This manager > will cache a map of primary and backup server. In the overriden > getConnectionWithTimeout method, i'd have super return me a connection that > i'll check and make sure that is valid and if not, i'll go to my cache, get > the backup host config and open up a connection to that. > > Let me know if you think this would be a good idea or not. > > Ankur >
Ankur My recommendation would be to implement the fail-over support as a service on top of HttpClient (1) execute a request against the primary host (2) if an exception is thrown, see whether it can be treated as recoverable (3) if so, mark the primary host as unavailable for a certain period time and retry the request against the secondary host (4) when the quarantine time elapses, mark the primary host as potentially available (5) repeat Hope this helps Oleg > On Mon, Mar 24, 2008 at 12:47 PM, Oleg Kalnichevski <[EMAIL PROTECTED]> > wrote: > > > > > On Thu, 2008-03-20 at 22:05 -0700, Ankur Shah wrote: > > > I am using httpclient to connect to a remote server. Now for each > > primary > > > server there's also a backup failover server that i must talk to if > > > connection attempts with the primary server fails. To achieve > > > this what i'd ideally like to do is have HttpClient use a custom factory > > > that tries to create a socket connection with the primary server and if > > that > > > fails (or times out), it'll go about talking to backup server (and > > retry a > > > few times before giving up altogether). > > > > > > Now, searching on the web, i did find references to a > > > MultiHomeProtocolSocketFactory (that extends DefaultSocketFactory) that > > is > > > presumably in apache contrib package. But what that does is that in the > > > overriden > > > createSocket method, it takes host as a param (among other thing) and > > then > > > simply does a InetAddress.getAllByName which is not what i want. From > > what i > > > understand this caters to a DNS based failover which is not the case > > here. > > > > > > What i'd ideally like to do is create a factory and have a createSocket > > > method that takes primary and secondary host and port as args and then > > tries > > > both. I am not sure though how can i make HttpConnection class > > > invoke my method. > > > > Ankur, > > > > What's the point of trying to implement the failover support on the > > ProtocolSocketFactory level? What's wrong with just retrying failed > > requests against a secondary server in case the primary one is > > unavailable? > > > > Oleg > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
