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Posted to users@tomcat.apache.org by Jared Walker <ja...@digitalredemption.com> on 2017/05/29 21:03:41 UTC

Tomcat 8.5.4, Backup Manager and Serializable objects in httpSession

Hello,

I have a question about how BackupManager enforces or performs session
replication.

I have added print outs to the serializing methods of an object I'm
binding to the http session.  When I run a simple test (login to the
server, shut it down, then try to refresh) I do not stay logged in.
In looking through my debug output I have noticed the following on the
server that is acting as the backup for session replication:

ClickSession:865 - Session read in:
ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
ClickSession:867 - Login ID: 1
1249:ClickSession is bound to HttpSession tj8Zu6ANdJdftMJHPAOa/JyTBiY=
by key com.clickfind.http.ClickSession

ClickSession:865 - Session read in:
ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
ClickSession:867 - Login ID: 18201

ClickSession:865 - Session read in:
ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
ClickSession:867 - Login ID: 18201

ClickSession:876 - Session write out:
ClickSession:877 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
ClickSession:878 - Login ID: 1

As you can see, initially the session is replicated across with a
guest login (ID=1).  Then there are subsequent messages that indicate
it is receiving updates to the session with an actual login value
(ID=18201).

However, when it goes to replicate the session to another server
(because the primary node was shut down) you can see that it writes
out the original value for the session (ID=1).

How can I ensure that the replication replaces the existing object in
the session attributes?

Thanks,
-Jared

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Re: Tomcat 8.5.4, Backup Manager and Serializable objects in httpSession

Posted by Jared Walker <ja...@digitalredemption.com>.
Hello,

The exception was not swallowed. It was just in a different log file
which I wasn't anticipating.

Thanks,
-Jared

On Mon, May 29, 2017 at 4:03 PM, Jared Walker
<ja...@digitalredemption.com> wrote:
> Hello,
>
> I have a question about how BackupManager enforces or performs session
> replication.
>
> I have added print outs to the serializing methods of an object I'm
> binding to the http session.  When I run a simple test (login to the
> server, shut it down, then try to refresh) I do not stay logged in.
> In looking through my debug output I have noticed the following on the
> server that is acting as the backup for session replication:
>
> ClickSession:865 - Session read in:
> ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
> ClickSession:867 - Login ID: 1
> 1249:ClickSession is bound to HttpSession tj8Zu6ANdJdftMJHPAOa/JyTBiY=
> by key com.clickfind.http.ClickSession
>
> ClickSession:865 - Session read in:
> ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
> ClickSession:867 - Login ID: 18201
>
> ClickSession:865 - Session read in:
> ClickSession:866 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
> ClickSession:867 - Login ID: 18201
>
> ClickSession:876 - Session write out:
> ClickSession:877 - Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY=
> ClickSession:878 - Login ID: 1
>
> As you can see, initially the session is replicated across with a
> guest login (ID=1).  Then there are subsequent messages that indicate
> it is receiving updates to the session with an actual login value
> (ID=18201).
>
> However, when it goes to replicate the session to another server
> (because the primary node was shut down) you can see that it writes
> out the original value for the session (ID=1).
>
> How can I ensure that the replication replaces the existing object in
> the session attributes?
>
> Thanks,
> -Jared

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Re: Tomcat 8.5.4, Backup Manager and Serializable objects in httpSession

Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Jared,

On 6/4/17 7:45 PM, Jared Walker wrote:
> I was able to figure out that this issue was caused by a developer 
> adding logging code to the serialization that had a NPE. 
> Unfortunately the exception was not printed out to catalina.out so
> it was very hard to find, but easy to fix.

Was Tomcat swallowing the NPE? If so, please let me know where that
happened. I've seen a few exception-swallowing pieces of Tomcat code,
and I've been wanting to at least log those instances.

- -chris

> On Tue, May 30, 2017 at 10:30 AM, Christopher Schultz 
> <ch...@christopherschultz.net> wrote: Jared,
> 
> On 5/29/17 5:03 PM, Jared Walker wrote:
>>>> Hello,
>>>> 
>>>> I have a question about how BackupManager enforces or
>>>> performs session replication.
>>>> 
>>>> I have added print outs to the serializing methods of an
>>>> object I'm binding to the http session.  When I run a simple
>>>> test (login to the server, shut it down, then try to refresh)
>>>> I do not stay logged in. In looking through my debug output I
>>>> have noticed the following on the server that is acting as
>>>> the backup for session replication:
>>>> 
>>>> ClickSession:865 - Session read in: ClickSession:866 -
>>>> Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 -
>>>> Login ID: 1 1249:ClickSession is bound to HttpSession 
>>>> tj8Zu6ANdJdftMJHPAOa/JyTBiY= by key 
>>>> com.clickfind.http.ClickSession
>>>> 
>>>> ClickSession:865 - Session read in: ClickSession:866 -
>>>> Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 -
>>>> Login ID: 18201
>>>> 
>>>> ClickSession:865 - Session read in: ClickSession:866 -
>>>> Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 -
>>>> Login ID: 18201
>>>> 
>>>> ClickSession:876 - Session write out: ClickSession:877 -
>>>> Session ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:878 -
>>>> Login ID: 1
>>>> 
>>>> As you can see, initially the session is replicated across
>>>> with a guest login (ID=1).  Then there are subsequent
>>>> messages that indicate it is receiving updates to the session
>>>> with an actual login value (ID=18201).
>>>> 
>>>> However, when it goes to replicate the session to another
>>>> server (because the primary node was shut down) you can see
>>>> that it writes out the original value for the session
>>>> (ID=1).
>>>> 
>>>> How can I ensure that the replication replaces the existing
>>>> object in the session attributes?
> 
> Can you post the code that generates the above output?
> 
> Are all those messages printed on the backup node (only)? Give us
> a little more information about the setup of your cluster.
> 
> -chris
>> 
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>> 
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> 
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Re: Tomcat 8.5.4, Backup Manager and Serializable objects in httpSession

Posted by Jared Walker <ja...@digitalredemption.com>.
Hello,

I was able to figure out that this issue was caused by a developer
adding logging code to the serialization that had a NPE.
Unfortunately the exception was not printed out to catalina.out so it
was very hard to find, but easy to fix.


Thanks,
-Jared

On Tue, May 30, 2017 at 10:30 AM, Christopher Schultz
<ch...@christopherschultz.net> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> Jared,
>
> On 5/29/17 5:03 PM, Jared Walker wrote:
>> Hello,
>>
>> I have a question about how BackupManager enforces or performs
>> session replication.
>>
>> I have added print outs to the serializing methods of an object
>> I'm binding to the http session.  When I run a simple test (login
>> to the server, shut it down, then try to refresh) I do not stay
>> logged in. In looking through my debug output I have noticed the
>> following on the server that is acting as the backup for session
>> replication:
>>
>> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
>> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 1
>> 1249:ClickSession is bound to HttpSession
>> tj8Zu6ANdJdftMJHPAOa/JyTBiY= by key
>> com.clickfind.http.ClickSession
>>
>> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
>> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 18201
>>
>> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
>> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 18201
>>
>> ClickSession:876 - Session write out: ClickSession:877 - Session
>> ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:878 - Login ID: 1
>>
>> As you can see, initially the session is replicated across with a
>> guest login (ID=1).  Then there are subsequent messages that
>> indicate it is receiving updates to the session with an actual
>> login value (ID=18201).
>>
>> However, when it goes to replicate the session to another server
>> (because the primary node was shut down) you can see that it
>> writes out the original value for the session (ID=1).
>>
>> How can I ensure that the replication replaces the existing object
>> in the session attributes?
>
> Can you post the code that generates the above output?
>
> Are all those messages printed on the backup node (only)? Give us a
> little more information about the setup of your cluster.
>
> - -chris
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> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
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Re: Tomcat 8.5.4, Backup Manager and Serializable objects in httpSession

Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Jared,

On 5/29/17 5:03 PM, Jared Walker wrote:
> Hello,
> 
> I have a question about how BackupManager enforces or performs
> session replication.
> 
> I have added print outs to the serializing methods of an object
> I'm binding to the http session.  When I run a simple test (login
> to the server, shut it down, then try to refresh) I do not stay
> logged in. In looking through my debug output I have noticed the
> following on the server that is acting as the backup for session
> replication:
> 
> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 1 
> 1249:ClickSession is bound to HttpSession
> tj8Zu6ANdJdftMJHPAOa/JyTBiY= by key
> com.clickfind.http.ClickSession
> 
> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 18201
> 
> ClickSession:865 - Session read in: ClickSession:866 - Session ID:
> tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:867 - Login ID: 18201
> 
> ClickSession:876 - Session write out: ClickSession:877 - Session
> ID: tj8Zu6ANdJdftMJHPAOa/JyTBiY= ClickSession:878 - Login ID: 1
> 
> As you can see, initially the session is replicated across with a 
> guest login (ID=1).  Then there are subsequent messages that
> indicate it is receiving updates to the session with an actual
> login value (ID=18201).
> 
> However, when it goes to replicate the session to another server 
> (because the primary node was shut down) you can see that it
> writes out the original value for the session (ID=1).
> 
> How can I ensure that the replication replaces the existing object
> in the session attributes?

Can you post the code that generates the above output?

Are all those messages printed on the backup node (only)? Give us a
little more information about the setup of your cluster.

- -chris
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