Re: Control different relation sequence
Exactly, that's what I would probably do as well. Once you are within a relation you want to wait for further actions, dump the $JUJU_RELATION_ID into a file and wait until you want to wake it up again. Hooks are guaranteed to be run in series, so you don't have to worry about concurrency issues around the file. On Wed, Sep 4, 2013 at 12:01 AM, Mike Sam mikesam...@gmail.com wrote: Thanks. Does this mean that the charm should cache the relation id's in a text file or something? On Tue, Sep 3, 2013 at 7:33 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: The relation-set command accepts a -r parameter which takes the relation id to act upon. You can pick the relation id of an executing hook from the JUJU_RELATION_ID environment variable. This way you can act across relations. Hopefully this will be better documented at some point. On Tue, Sep 3, 2013 at 11:23 PM, Mike Sam mikesam...@gmail.com wrote: Thanks Gustavo but I did not quite get your point. The problem is that for the new unit for service A, the dependent hooks are on two different independent relationships. I mean I can control when the new unit of Service A has properly established a relation with all the units of service B on say relation x_relation_changed, but how do I make all the units of service C to now trigger the y_relation_changed hook of the Service A unit because the unit is ready to process them? How do I make y_relation_changed hook to get triggered AGAIN (in case it has already been triggered but ignored because relation with service B was not done setting up) when x_relation_changed see fit? Would you please explain your point is the Service A, B, C context of my example? On Tue, Sep 3, 2013 at 6:38 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: Hi Mike, You cannot control the sequence in which the hooks are executed, but you have full control of what you do when the hooks do execute. You can choose to send nothing to the other side of the relation until its time to report that a connection may now be established, and when you do change the relation, the remote hook will run again to report the change. On Tue, Sep 3, 2013 at 10:17 PM, Mike Sam mikesam...@gmail.com wrote: Imagine a unit needs to be added to an existing service like service A. Service A is already in relations with other services like Service B and Service C on different requires. For the new unit on Service A to work, it needs to first process the relation_joined and relation_changed with the units of service B before it could process relation_joined and relation_changed with the units of service C. Is there a way to enforce such desired sequence relationship establishment at the charm level? In other words, I do not think we can control the hook execution sequence of different relationships officially but then I am wondering how can we do a situation like above nicely? Thanks, Mike -- Juju-dev mailing list juju-...@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev -- gustavo @ http://niemeyer.net -- gustavo @ http://niemeyer.net -- gustavo @ http://niemeyer.net -- Juju mailing list Juju@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju
Re: Control different relation sequence
Exactly, that's what I would probably do as well. Once you are within a relation you want to wait for further actions, dump the $JUJU_RELATION_ID into a file and wait until you want to wake it up again. Hooks are guaranteed to be run in series, so you don't have to worry about concurrency issues around the file. On Wed, Sep 4, 2013 at 12:01 AM, Mike Sam mikesam...@gmail.com wrote: Thanks. Does this mean that the charm should cache the relation id's in a text file or something? On Tue, Sep 3, 2013 at 7:33 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: The relation-set command accepts a -r parameter which takes the relation id to act upon. You can pick the relation id of an executing hook from the JUJU_RELATION_ID environment variable. This way you can act across relations. Hopefully this will be better documented at some point. On Tue, Sep 3, 2013 at 11:23 PM, Mike Sam mikesam...@gmail.com wrote: Thanks Gustavo but I did not quite get your point. The problem is that for the new unit for service A, the dependent hooks are on two different independent relationships. I mean I can control when the new unit of Service A has properly established a relation with all the units of service B on say relation x_relation_changed, but how do I make all the units of service C to now trigger the y_relation_changed hook of the Service A unit because the unit is ready to process them? How do I make y_relation_changed hook to get triggered AGAIN (in case it has already been triggered but ignored because relation with service B was not done setting up) when x_relation_changed see fit? Would you please explain your point is the Service A, B, C context of my example? On Tue, Sep 3, 2013 at 6:38 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: Hi Mike, You cannot control the sequence in which the hooks are executed, but you have full control of what you do when the hooks do execute. You can choose to send nothing to the other side of the relation until its time to report that a connection may now be established, and when you do change the relation, the remote hook will run again to report the change. On Tue, Sep 3, 2013 at 10:17 PM, Mike Sam mikesam...@gmail.com wrote: Imagine a unit needs to be added to an existing service like service A. Service A is already in relations with other services like Service B and Service C on different requires. For the new unit on Service A to work, it needs to first process the relation_joined and relation_changed with the units of service B before it could process relation_joined and relation_changed with the units of service C. Is there a way to enforce such desired sequence relationship establishment at the charm level? In other words, I do not think we can control the hook execution sequence of different relationships officially but then I am wondering how can we do a situation like above nicely? Thanks, Mike -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev -- gustavo @ http://niemeyer.net -- gustavo @ http://niemeyer.net -- gustavo @ http://niemeyer.net -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev
Re: Control different relation sequence
The missing command here is relation-ids to list the relation ids of a given relation name. JUJU_RELATION_ID gives the current relation be executed for, to trigger/inspect state on other relations, the relation-ids command can be used to find their id, which can be passed to relation-get/set with -r. Any mutations of the other relation state via relation-set will trigger change hooks on remote related units. cheers, Kapil On Tue, Sep 3, 2013 at 10:33 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: The relation-set command accepts a -r parameter which takes the relation id to act upon. You can pick the relation id of an executing hook from the JUJU_RELATION_ID environment variable. This way you can act across relations. Hopefully this will be better documented at some point. On Tue, Sep 3, 2013 at 11:23 PM, Mike Sam mikesam...@gmail.com wrote: Thanks Gustavo but I did not quite get your point. The problem is that for the new unit for service A, the dependent hooks are on two different independent relationships. I mean I can control when the new unit of Service A has properly established a relation with all the units of service B on say relation x_relation_changed, but how do I make all the units of service C to now trigger the y_relation_changed hook of the Service A unit because the unit is ready to process them? How do I make y_relation_changed hook to get triggered AGAIN (in case it has already been triggered but ignored because relation with service B was not done setting up) when x_relation_changed see fit? Would you please explain your point is the Service A, B, C context of my example? On Tue, Sep 3, 2013 at 6:38 PM, Gustavo Niemeyer gustavo.nieme...@canonical.com wrote: Hi Mike, You cannot control the sequence in which the hooks are executed, but you have full control of what you do when the hooks do execute. You can choose to send nothing to the other side of the relation until its time to report that a connection may now be established, and when you do change the relation, the remote hook will run again to report the change. On Tue, Sep 3, 2013 at 10:17 PM, Mike Sam mikesam...@gmail.com wrote: Imagine a unit needs to be added to an existing service like service A. Service A is already in relations with other services like Service B and Service C on different requires. For the new unit on Service A to work, it needs to first process the relation_joined and relation_changed with the units of service B before it could process relation_joined and relation_changed with the units of service C. Is there a way to enforce such desired sequence relationship establishment at the charm level? In other words, I do not think we can control the hook execution sequence of different relationships officially but then I am wondering how can we do a situation like above nicely? Thanks, Mike -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev -- gustavo @ http://niemeyer.net -- gustavo @ http://niemeyer.net -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev
Re: Control different relation sequence
Hi Mike, You cannot control the sequence in which the hooks are executed, but you have full control of what you do when the hooks do execute. You can choose to send nothing to the other side of the relation until its time to report that a connection may now be established, and when you do change the relation, the remote hook will run again to report the change. On Tue, Sep 3, 2013 at 10:17 PM, Mike Sam mikesam...@gmail.com wrote: Imagine a unit needs to be added to an existing service like service A. Service A is already in relations with other services like Service B and Service C on different requires. For the new unit on Service A to work, it needs to first process the relation_joined and relation_changed with the units of service B before it could process relation_joined and relation_changed with the units of service C. Is there a way to enforce such desired sequence relationship establishment at the charm level? In other words, I do not think we can control the hook execution sequence of different relationships officially but then I am wondering how can we do a situation like above nicely? Thanks, Mike -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev -- gustavo @ http://niemeyer.net -- Juju-dev mailing list Juju-dev@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju-dev
