Re: [p2-dev] Use of ProvisionException.REPOSITORY_NOT_FOUND?

[John Arthorne <John_Arthorne@xxxxxxxxxx>]

The purpose of this behaviour is to
allow different repository factories a chance to load a repository at the
given location. For example, if there is no content.jar we want to allow
the update site repository a chance to look for a site.xml file. A repository
factory can "pass" by returning NOT_FOUND, and the repository
manager proceeds to the next factory. If the factory finds a file, but
fails while loading it, it can return FAILED_READ to indicate, "Yes,
this is a simple metadata repository, but it can't be read". This
prevents the repository manager from trying again with a different factory.

In the case of connection failures like
"unknown host" or "connection refused", throwing something
other than "NOT_FOUND" makes sense to me. If there is a connection
failure, chances are another repository type won't have any better luck.
This would allow us to propagate a more informative message about the state
of the repository back to the user. I think that test might just be making
a bad assumption, which we can fix up along with your changes to return
more useful messages.

Henrik Lindberg <henrik.lindberg@xxxxxxxxxxxxxx>
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03/16/2009 05:50 PM

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Subject	Re: [p2-dev] Use of ProvisionException.REPOSITORY_NOT_FOUND?

Thanks John,
Question is which exceptions to interpret as "not
found". The current impl (before patch in 216278) hides many of these
issues - for instance, the cache manager will look for a jar and an xml
file, and determines their existence via a call to Transport.getLastModified,
and this method returns 0 when there is an error, and this is interpreted
as a "file not found" - but it could just as well be a "unknown
host", or "connection refused". 

In the patch, the getLastModified throws exceptions on
errors so they can be reported to the user.

The test that failed was: MetadataRepositoryManagerTest.testFailedConnection()
it tries to connect to "invalid://eclipse" - which my patch originally
reported as a REPOSITORY_FAILED_READ, but the test wants REPOSITORY_NOT_FOUND.
The test is wrong if the authoritative interpretation of "invalid:"
should be made by ECF, but is correct if a meta data repository loader
could determine that "invalid:" is in fact a scheme that it understands
and the test to determine which loader to load the repo is performed by
trying to load using this URI. If in fact, it is the repository loader
that decides, then all repositories should typically return REPOSITORY_NOT_FOUND,
because they do not know if some other repository wants to try to connect
to a repo on a special port, with (additional) parameters, or indeed always
add an "x" to the hostname (or something equally crazy). 

I suspect that the intention is that repositories decide,
and that the only errors that should be reported as "FAILED_READ"
are IO errors when reading the "found file(s)".

Henrik Lindberg
henrik.lindberg@xxxxxxxxxxxxxx



On Mar 16, 2009, at 3:08 PM, John Arthorne wrote:


Which tests fail? Can you point out the failure, or attach a patch somewhere
with your changes that cause test failures? The only important distinction
is that a NOT_FOUND exception will cause the repository manager to keep
trying with another repository type, whereas other exceptions will result
in the repository manager not trying another repository type (because the
repository is there, but there were problems reading it). See the javadoc
in MetadataRepositoryFactory#load for details.

Henrik Lindberg <henrik.lindberg@xxxxxxxxxxxxxx>
Sent by: p2-dev-bounces@xxxxxxxxxxx

03/11/2009 10:01 PM

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Subject	[p2-dev] Use of ProvisionException.REPOSITORY_NOT_FOUND?

When testing repository loading and using invalid URI's to test errors
 
- tests fail if the Status.getCode() is not REPOSITORY_NOT_FOUND.
I saw one comment that said that "this status code is expected, since
 
all others will be logged".

I wonder how the status codes should be used? There are codes for  
ACCESS denied, INVALID location, etc. Wouldn't it be more appropriate  
to use those when the
cause is known? I now have statuses with more details working, and I  
selected what I thought were suitable codes from ProvisionException  
only to find that tests fail...

Can someone shed some light on how it is supposed to work?

Henrik Lindberg
henrik.lindberg@xxxxxxxxxxxxxx


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