On 06/01/12 11:47, Konstantin Kolinko wrote:
2012/1/6 Brian Burch<br...@pingtoo.com>:
I am developing some new unit tests to validate SingleSignOn and
Authenticator logic. I have used this existing test class as my template:
org.apache.catalina.authenticator.TestDigestAuthenticator
.. which extends org.apache.catalina.startup.TomcatBaseTest.
I noticed that TestDigestAuthenticator sets up its own MapRealm and assigns
it to its single Context. I thought this logic was unnecessary, and so my
own initial test logic simply used the default RealmBase provided by the
underlying Tomcat instance. I add my test user and role to that. It worked
fine with my simple cases, however...
To test SSO, I need to set up two Contexts under the same Realm. I see the
following message in the output log:
INFO: The start() method was called on component [Realm[Simple]] after
start() had already been called. The second call will be ignored.
I know it is an INFO message. I know the second start (and its associated
stop) are ignored and therefore are harmless. However, I am reluctant to
simply shrug and ignore it. My instincts tell me something isn't right.
I have done quite a lot of investigating, but the underlying logic is very
hard for me to follow. Here is what I am sure about:
1. The message is ONLY emitted in tests that create two Contexts and each
have the same Realm assigned with setRealm.
2. The message is NOT emitted at the time the Contexts are created and
defined (servlets, security constraints, etc).
3. The message IS emitted after the Tomcat.start method is called.
4. The message is emitted by one of the two threads which are started on
behalf of my two contexts. The messages are issued by the start and stop
methods in the abstract class org.apache.catalina.util.LifecycleBase.
5. org.apache.catalina.realm.RealmBase extends
org.apache.catalina.util.LifecycleMBeanBase which extends LifecycleBase.
My currently unanswered questions are:
1. Is this message normal? (I don't see it when I start multiple contexts
under a real tomcat server, but perhaps the logging properties are
different).
2. Why isn't the redundant startup of the Realm detected earlier and simply
avoided (maybe the Threads are intended to race to be first with startup -
but then I think the message should be debug level and not sound so scary).
Please don't waste your time investigating this for me. I am only asking the
question because I don't want too get side-tracked if one of you already
knows the answers to my questions. I'd like to settle the matter quickly and
get back to my original task!
Thanks for listening,
The message is expected. I would say that the configuration is wrong,
or at least unusual.
If you look at the default server.xml file you will note that the
<Realm> element there belongs to Engine. That is why it is started
once.
I agree, and this is what the TomcatBaseTest expects. If you "tickle"
tomcat with TomcatBaseTest.getTomcatInstance() and then with
Tomcat.getDefaultRealm(), a new default RealBase (memory) instance is
definitely created.
When Contexts are created and their context.xml files are parsed, the
Contexts always get distinct new Realm instances.
Instead of assigning the same Realm instance to both Contexts you
should assign it to an upper container (I have not looked at the API
though). Or maybe you can have different Realm instances, but which
connect to the same backing storage?
When the StandardEngine (extending ContainerBase) thread starts, I would
expect percolating getRealm calls (from Context to Host to Engine) to
eventually arrive at the already-defined Tomcat default Realm. HOWEVER,
StandardEngine overrides the ContainerBase.getRealm method and ensures
that an unconfigured JAAS Realm is instantiated as the default for the
Context, because it cannot locate its parent (the field is certainly
null, not tomcat), so it decides to use this JAAS as the backstop.
This looks to me as if some refactoring between tomcat 5 and 6 left the
Tomcat default memory realm orphaned from the StandardEngine, which now
operates independently and establishes a completely different default
realm. Perhaps the right hand no longer knows what the left hand is
doing????
Funny thing is that I googled this:
http://tomcat.10.n6.nabble.com/default-realm-set-to-JAASRealm-in-StandardEngine-td2005479.html
... and your name (Konstantin) is all over it! Can you cast you mind
back 4 months and try to give me a clue about the history of this change
to the logic?
My feeling is that we need to stop StandardEngine from unilaterally
creating an unconfigured JAAS default Realm... and help the poor thing
find its true parent, i.e. tomcat, which has a perfectly serviceable
default memory realm just waiting to be used!
(apologies for the mild sarcasm - I can see you are very busy on other
issues),
Brian
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