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From Kirk Lund <kl...@pivotal.io>
Subject Re: Loner changes its membership port when starting an acceptor
Date Wed, 16 Jan 2019 21:27:30 GMT
It's not using toString(). It's just using DistributedMember.getName().
This is implemented by InternalDistributedMember.getName() which delegates
to NetMember.getName(). Are you saying we should add a new method to
DistributedMember instead of using getName()?

The mbeans are categorized a type of Member or Distributed. Member means
the mbean represents something about a member, while the other type means
that the mbean represents something about the DistributedSystem/Cluster
(aggregating all Members together in some way). When the type is Member,
the ObjectName contains:

"type=Member,member={0}"

MBeanJMXAdapter creates the ObjectNames by filling in that parameter with
DistributedMember.getName(). We originally documented that the ObjectNames
would contain the DistributedMember.getName(), but we could change that by
adding a new getMBeanName() method or something like that. I think we
originally thought it would be nice for the User if they could simply refer
to DistributedMember.getName() as being the same value as we use in the JMX
ObjectName.

On Tue, Jan 15, 2019 at 11:28 AM Bruce Schuchardt <bschuchardt@pivotal.io>
wrote:

> Yeah, let's fix this, but let's not require the toString() of an object
> to never change.  Let's add another method that returns a Bean
> identifier and is documented to never change.
>
> On 1/15/19 9:45 AM, Kirk Lund wrote:
> > Sorry about the confusion. I meant that the change of membership port
> > results in DistributedMember returning a different string from its
> > getName() method.
> >
> > We discovered this because the JMX layer has some error handling that
> > results in suppressing this failure, so the failure was being hidden. We
> > cleaned up the error handling and saw quite a few failures in precheckin
> > caused by this. I figured it was more correct to fix the underlying
> problem
> > rather than restore the suppression of this bug.
> >
> > On Tue, Jan 15, 2019 at 7:47 AM Bruce Schuchardt <bschuchardt@pivotal.io
> >
> > wrote:
> >
> >> Actually the formatting code would go in InternalDistributedMember.  The
> >> JMX code already has a special method for handling that class.  I was
> >> thrown off by the reference to a non-existant getName() method in
> >> LonerDistributionManager.
> >>
> >> On 1/15/19 7:34 AM, Bruce Schuchardt wrote:
> >>> I think we could solve this by either moving the ID formatting code to
> >>> the DistributionManager implementations & having
> >>> LonerDistributionManager omit the port number or modify the
> >>> client/server handshake to not install a port number when connecting
> >>> to a remote GatewayReceiver.  I guess the latter wouldn't work if the
> >>> bean is in a real client cache.
> >>>
> >>> The installation of a port number was implemented to prevent duplicate
> >>> membership IDs in client caches when clients are being spun up in
> >>> parallel on the same machine.  However there is also a "unique ID" in
> >>> LonerDistributionManager that was supposed to address this problem but
> >>> apparently didn't.
> >>>
> >>> On 1/14/19 4:45 PM, Kirk Lund wrote:
> >>>> So I was stepping through some WAN tests in IJ debugger (on develop
> >>>> with no
> >>>> changes) and discovered that any MXBeans that are created before
> >>>> starting a
> >>>> server port (either using CacheServer or GatewayReceiver) are broken
> and
> >>>> fail to be updated after that -- the ObjectNames include the
> >>>> DistributedMember.getName(). Turns out some JMX code is eating an NPE
> >>>> that's caused because the LonerDistributionManager changes its
> >>>> membership
> >>>> port when an acceptor endpoint is started up.
> >>>>
> >>>> Below is the method in LonerDistributionManager (with some other
> >>>> issues as
> >>>> well) that does this updating. We either need to make a lot of
> >>>> changes to
> >>>> the JMX code to fix this or we need to make one small change to
> >>>> LonerDistributionManager (ie, to delete this method). Question: do we
> >>>> really need the DistributedMember of a Loner to change its getName()
> >>>> which
> >>>> includes the membership port that changed?
> >>>>
> >>>>     /**
> >>>>      * update the loner port with an integer that may be more unique
> >>>> than the
> >>>> default port (zero).
> >>>>      * This updates the ID in place and establishes new default
> >>>> settings for
> >>>> the manufacture of new
> >>>>      * IDs.
> >>>>      *
> >>>>      * @param newPort the new port to use
> >>>>      */
> >>>>     public void updateLonerPort(int newPort) {
> >>>>       this.logger.config(
> >>>>           String.format("Updating membership port.  Port changed from
> >>>> %s to
> >>>> %s.  ID is now %s",
> >>>>               new Object[] {this.lonerPort, newPort, getId()}));
> >>>>       this.lonerPort = newPort;
> >>>>       *this.getId().setPort(this.lonerPort);*
> >>>>     }
> >>>>
>

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