I'm looking for ideas on how to use the dispatcher module with a list file that is frequently updated by another process (specifically, it checks the availability of the remote machines, and also interacts with the heartbeat program).
In the past, I've always used an exec_dst() call to run an external program which does this, but would now like to migrate to using dispatcher for performance. If that's not possible, I'll go back to the old method.
I've considered adding a call to ds_select_dst() to call ds_destroy_list(); ds_load_list() on each request with file locking. It looks like it should work. Has anyone implemented this? Does it work? Does it have a significant impact on performance?
I'd also be open to having the other process write to a database table, which then SER reads. I'm not sure what's the best mechanism within SER to look up the table - perhaps avpops? I'd even be willing write a new module to do it - 'dispatcher_db' perhaps, but this wouldn't be in the short future.
On 08/09/05 13:51, Alistair Cunningham wrote:
I'm looking for ideas on how to use the dispatcher module with a list file that is frequently updated by another process (specifically, it checks the availability of the remote machines, and also interacts with the heartbeat program).
In the past, I've always used an exec_dst() call to run an external program which does this, but would now like to migrate to using dispatcher for performance. If that's not possible, I'll go back to the old method.
I've considered adding a call to ds_select_dst() to call ds_destroy_list(); ds_load_list() on each request with file locking. It looks like it should work. Has anyone implemented this? Does it work? Does it have a significant impact on performance?
there is on the todo list to add support to reload the destination list upon a fifo command or other external event. Destroying and reloading the list for each request will have quite big performance impact, so it is better to do it only when needed.
I'd also be open to having the other process write to a database table, which then SER reads. I'm not sure what's the best mechanism within SER to look up the table - perhaps avpops? I'd even be willing write a new module to do it - 'dispatcher_db' perhaps, but this wouldn't be in the short future.
Do you want a db lookup for each request, or when the server starts and then use a cache?
Daniel
Daniel-Constantin Mierla wrote:
On 08/09/05 13:51, Alistair Cunningham wrote:
I've considered adding a call to ds_select_dst() to call ds_destroy_list(); ds_load_list() on each request with file locking. It looks like it should work. Has anyone implemented this? Does it work? Does it have a significant impact on performance?
there is on the todo list to add support to reload the destination list upon a fifo command or other external event. Destroying and reloading the list for each request will have quite big performance impact, so it is better to do it only when needed.
That would be fine. Any idea when this will be implemented?
I'd also be open to having the other process write to a database table, which then SER reads. I'm not sure what's the best mechanism within SER to look up the table - perhaps avpops? I'd even be willing write a new module to do it - 'dispatcher_db' perhaps, but this wouldn't be in the short future.
Do you want a db lookup for each request, or when the server starts and then use a cache?
Probably on each request, as the database would be updated behind SER's back by the monitoring process.
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Alistair Cunningham -
Daniel-Constantin Mierla