Commit Graph

482 Commits

Author SHA1 Message Date
Clinton Gormley e143c6e460 Docs: Prepare plugin and integration docs for 2.0
* Centralised plugin docs in docs/plugins/
* Moved integrations into same docs
* Moved community clients into the clients section of the docs
* Removed docs/community

Closes #11734
Closes #11724
Closes #11636
Closes #11635
Closes #11632
Closes #11630
Closes #12046
Closes #12438
Closes #12579
2015-08-15 18:02:43 +02:00
Simon Willnauer b447e2ae99 Move master to [2.1.0-SNAPSHOT] 2015-08-14 23:44:06 +02:00
Ryan Ernst f3d63095db Merge branch 'master' into resolve_your_own_config
Conflicts:
	core/src/main/java/org/elasticsearch/env/Environment.java
	core/src/test/java/org/elasticsearch/index/analysis/commongrams/CommonGramsTokenFilterFactoryTests.java
	core/src/test/java/org/elasticsearch/index/analysis/synonyms/SynonymsAnalysisTest.java
	plugins/analysis-kuromoji/src/test/java/org/elasticsearch/index/analysis/KuromojiAnalysisTests.java
2015-08-14 03:34:26 -07:00
Ryan Ernst be638fb6ef Internal: Remove Environment.resolveConfig
This method has multiple modes of resolving config files by
first looking in the config directory, then on the classpath,
and finally by prefixing with "config/" on the classpath.

Most of the places taking advantage of this were tests, so they
did not have to setup a real home dir with config. The only place
that was really relying on it was the code which loads names.txt
to randomly choose a node name.

This change fixes test to setup fake home dirs with their config
files. It also makes the logic for finding names.txt explicit:
look in config dir, and if it doesn't exist, load /config/names.txt
from the classpath.
2015-08-14 03:03:47 -07:00
Ryan Ernst 6dcfda99e8 Internal: Remove ClassLoader from Settings
Settings currently has a classloader member, which any user (plugin
or core ES code) can access to load classes/resources. This is extremely
error prone as setting the classloder on the Settings instance is a
public method. Furthermore, it is not really necessary. Classes that
need resources should load resources using normal means
(getClass().getResourceAsStream). Those that need classes
should use Class.forName, which will load the class with the
same classloader as the calling class. This means, in the few
places where classes are loaded by string name, they will use
the appropriate loader: either the default classloader which loads
core ES code, or a child classloader for each plugin.

This change removes the classloader member from Settings, as
well as other classloader related uses (except for a handful
of cases which must use a classloader, at least for now).
2015-08-13 23:55:27 -07:00
Ryan Ernst c16772b0fc Undo accidental commit of crap
This reverts commit 589eecf55d.
2015-08-13 19:39:55 -07:00
Ryan Ernst 589eecf55d Fourth time's a charm, one more mock class to add to test jar 2015-08-13 19:36:53 -07:00
David Pilato 48ef9e3cfb Merge branch 'aws/base_path' 2015-08-13 15:29:00 +02:00
Adrien Grand 28708f8013 Tests: Fix SimpleIcuAnalysisTests to not load a non-existent configuration file. 2015-08-13 14:39:10 +02:00
Simon Willnauer 605253a39f Cut over master to 2.0.0-SNAPSHOT 2015-08-12 21:16:08 +02:00
David Pilato beb7e16a43 [cloud-gce] replace integration tests by unit tests
We use google transport mock as we can simulate whatever JSON answer GCE platform will send us and really test Gce implementation.

We also remove GceSimpleITest as the goal of this class was only to check that when we start elasticsearch with this plugin, elasticsearch works fine.
We don't need that anymore as we now have RestIT which do that right (and better)!

Closes #12622
2015-08-12 17:47:53 +02:00
David Pilato 99fccddcf2 [cloud-gce] update to GCE API v1-rev71-1.20.0
Closes #12835
2015-08-12 17:38:04 +02:00
Nik Everett e4e60774c1 Merge pull request #12787 from nik9000/configured_plugin
QA: Add configuration to the jvm-example plugin
2015-08-12 07:36:34 -07:00
Clinton Gormley 29d1924d78 Add licenses/no_deps.txt to plugins/jvm-example to quiet the license checker 2015-08-11 19:55:41 +02:00
Nik Everett e807499c29 Merge configured-plugin into jvm-example plugin 2015-08-11 07:36:32 -07:00
Ryan Ernst 40f119d85a This method on settings loaded a class, based on a setting value, using
the default classloader. It had all kinds of leniency in how the
classname was found, and simply cannot work with plugins having isolated
classloaders.

This change removes that method. Some of the uses of it were for custom
extension points, like custom repository or discovery types. A lot were
just there to plugin mock implementations for tests. For the settings
that were legitimate, all now support plugins adding the given setting
via onModule. For those that were specific to tests for mocks, they now
use Classes.loadClass (a helper around Class.forName). This is a
temporary measure until (in a future PR) tests can change the
implementation via package private statics.

I also removed a number of unnecessary intermediate modules, added a
"jvm-example" plugin that can be filled in in the future as a smoke test
for breaking plugins, and gave some documentation to "spawn" modules
interface.

closes #12643
closes #12656
2015-08-10 14:04:45 -07:00
Colin Goodheart-Smithe 6abc69c488 Packaging: Makes sure all POMs contain a description
Adds an explicit description the RPM package so it doesn't inherit the description from the POM.

Closes #12550

Also, modified descriptions for deb and rpm packages to be the same and to reference the documentation rather than listing features that are out of date.
2015-08-10 15:21:24 +01:00
David Pilato f843a1375f [cloud-aws] add support for base_path in elasticsearch.yml
Related to https://github.com/elastic/elasticsearch-cloud-aws/issues/230

We now can support setting a global `base_path` in `elasticsearch.yml` using `repositories.s3.base_path` key.
2015-08-10 10:40:44 +02:00
Clinton Gormley a0774d0f48 no_deps.txt should be in the licenses/ directory in plugins 2015-08-09 20:16:11 +02:00
Clinton Gormley bc7dbce4fe Enable the license checker for plugins without third party deps too 2015-08-09 19:07:45 +02:00
Clinton Gormley 205262c737 Enable the license checker over distribution/* and plugins/*
Moved the license checker config into the parent pom, and overrede
the license dir/target-to-check in distributions/pom.

Disabled the license checker explicitly for projects which run integration
tests but have no licenses dir:

* core
* distribution
* qa
* plugins/delete-by-query
* plugins/mapper-size
* plugins/site-example

Closes #12752
Closes #12754
2015-08-09 18:18:59 +02:00
Robert Muir d1a5068b77 Merge branch 'master' into integ_randomization 2015-08-06 14:51:00 -04:00
Robert Muir 7414d19d28 Support jenkins randomization in integration tests 2015-08-06 14:48:27 -04:00
Adrien Grand 5dd5936fad Move the `_size` mapper to a plugin.
This is one of our esoteric metadata mappers so I think we should distribute
it in a plugin rather than in elasticsearch core.

This introduces one limitation: the value of the `_size` parameter is not
retrievable for documents that are only in the transaction log.
2015-08-06 20:35:22 +02:00
Adrien Grand b16e2d95af Allow scripts to expose whether they use the `_score`.
This commit adds a new API to allow scripts to say whether they need scores.
In practice, only the `expression` script engine makes use of it correctly,
other engines just return `true` since they can't predict whether they'll
need scores. This should make scripted aggregations and `function_query`
faster as we'll now be able to pass needsScores=false to Query.createWeight.
2015-08-06 17:25:51 +02:00
Robert Muir 5fe49e4420 cleanup skipping everywhere 2015-08-05 21:45:09 -04:00
xuzha 333ca689d3 Add retry when checking s3 bucket 2015-08-04 15:58:15 -07:00
Robert Muir 6f9a067197 Change master branch back to 2.0-beta1 2015-08-04 15:38:21 -04:00
Robert Muir 29d73accdd Merge pull request #12639 from rmuir/improve_integ
Don't use port 9200/9300 for integration tests
2015-08-04 13:09:47 -04:00
Robert Muir f1019ace3b Fix plugins integ dependencies and apply cleanups 2015-08-04 09:59:19 -04:00
Robert Muir cf6fe6cdcd Don't use port 9200/9300 for integration tests 2015-08-04 09:25:44 -04:00
Simon Willnauer 6753f7f03e Cut over master to 2.0.0-SNAPSHOT 2015-08-04 10:54:12 +02:00
Robert Muir a0a177222b fix typo in assume() when running from IDE 2015-08-03 23:57:27 -04:00
Robert Muir 64850c0539 Improve site-example integ test to test served contents.
Closes #12578
2015-08-03 23:47:36 -04:00
Ryan Ernst 1e12d03252 Tests: Rename base tests cases to use "TestCase" suffix
Most of the abstract base test classes we have were previously @Ignored.
However, there were also some other tests ignored. Having two ways to
quiet tests is confusing, and clearly it has caused some tests
to get lost in the fold.

This change moves all base test classes to use the "TestCase" suffix,
which is not picked up by the test class name pattern. It also removes
@Ignore from (almost) all tests, and adds it to forbidden apis.
And since we were renaming, I shorted base test class names to use
"ES" instead of "Elasticsearch". I type this a lot of types a day,
and I have heard others express a similar desire for a shorter name.

closes #10659
2015-08-03 17:43:00 -07:00
Ryan Ernst 32a5c20b33 Tests: Forbid @Slow
Now that all uses of @Slow are gone, we can forbid this annotations use
so tests are not confusing. Follow up to #12617.
2015-08-03 16:43:09 -07:00
Ryan Ernst be941f0669 Tests: Remove uses of @Slow and @Integration
Now that integ tests are moved into `mvn verify`, we don't really have
a need for @Slow, and especially not @Integration. This removes
uses of the first, and completely removes uses of the latter.
2015-08-03 16:26:07 -07:00
David Pilato ac89f43d11 Merge pull request #12604 from dadoonet/maven/rename-site-example
[build] rename site example plugin to site-example
2015-08-03 18:45:13 +02:00
David Pilato 1b0492f800 [build] rename site example plugin to site-example
Just to be consistent in plugin naming convention we have today: `plugin_type-plugin_name`

So it's a `site` plugin.
2015-08-03 18:41:04 +02:00
Robert Muir 379ffdb8ee Add integration test phase for elasticsearch core/ 2015-08-03 09:43:11 -04:00
Robert Muir c5b91b9058 Merge pull request #12589 from rmuir/shading_cleanup
Fix shaded jar packaging
2015-08-03 08:10:50 -04:00
Tanguy Leroux 3537610760 Add comment about AWS S3 "doesBucketExist()" method 2015-08-03 11:02:16 +02:00
Robert Muir fef55348f9 clean up .zip handling so its not uselessly downloaded in the build 2015-08-01 09:10:03 -04:00
Robert Muir f804ec3cd9 cleanup 2015-07-31 10:05:11 -04:00
Robert Muir fd8e92a18a don't represent site plugins with 'null' anymore 2015-07-31 09:41:39 -04:00
Jason Tedor b0564cb75c Add integration test for Azure snapshot repository bug
This commit adds an integration test that replicates the Azure snapshot repository bug in elastic/elasticsearch-cloud-azure#51.

Closes elastic/elasticsearch-cloud-azure#100
2015-07-27 13:52:51 -04:00
Jason Tedor 45fadd4955 Use correct settings keys for setting container, base path and chunk size in Azure integration test 2015-07-27 13:37:58 -04:00
Robert Muir 4040f194f5 Refactor pluginservice
Closes #12367

Squashed commit of the following:

commit 9453c411798121aa5439c52e95301f60a022ba5f
Merge: 3511a9c 828d8c7
Author: Robert Muir <rmuir@apache.org>
Date:   Wed Jul 22 08:22:41 2015 -0400

    Merge branch 'master' into refactor_pluginservice

commit 3511a9c616503c447de9f0df9b4e9db3e22abd58
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 21:50:15 2015 -0700

    Remove duplicated constant

commit 4a9b5b4621b0ef2e74c1e017d9c8cf624dd27713
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 21:01:57 2015 -0700

    Add check that plugin must specify at least site or jvm

commit 19aef2f0596153a549ef4b7f4483694de41e101b
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 20:52:58 2015 -0700

    Change plugin "plugin" property to "classname"

commit 07ae396f30ed592b7499a086adca72d3f327fe4c
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 23:36:05 2015 -0400

    remove test with no methods

commit 550e73bf3d0f94562f4dde95239409dc5a24ce25
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 23:31:58 2015 -0400

    fix loading to use classname

commit 04463aed12046da0da5cac2a24c3ace51a79f799
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 23:24:19 2015 -0400

    rename to classname

commit 9f3afadd1caf89448c2eb913757036da48758b2d
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 20:18:46 2015 -0700

    moved PluginInfo and refactored parsing from properties file

commit df63ccc1b8b7cc64d3e59d23f6c8e827825eba87
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 23:08:26 2015 -0400

    fix test

commit c7febd844be358707823186a8c7a2d21e37540c9
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 23:03:44 2015 -0400

    remove test

commit 017b3410cf9d2b7fca1b8653e6f1ebe2f2519257
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 22:58:31 2015 -0400

    fix test

commit c9922938df48041ad43bbb3ed6746f71bc846629
Merge: ad59af4 01ea89a
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 22:37:28 2015 -0400

    Merge branch 'master' into refactor_pluginservice

commit ad59af465e1f1ac58897e63e0c25fcce641148a7
Author: Areek Zillur <areek.zillur@elasticsearch.com>
Date:   Tue Jul 21 19:30:26 2015 -0400

    [TEST] Verify expected number of nodes in cluster before issuing shardStores request

commit f0f5a1e087255215b93656550fbc6bd89b8b3205
Author: Lee Hinman <lee@writequit.org>
Date:   Tue Jul 21 11:27:28 2015 -0600

    Ignore EngineClosedException during translog fysnc

    When performing an operation on a primary, the state is captured and the
    operation is performed on the primary shard. The original request is
    then modified to increment the version of the operation as preparation
    for it to be sent to the replicas.

    If the request first fails on the primary during the translog sync
    (because the Engine is already closed due to shadow primaries closing
    the engine on relocation), then the operation is retried on the new primary
    after being modified for the replica shards. It will then fail due to the
    version being incorrect (the document does not yet exist but the request
    expects a version of "1").

    Order of operations:

    - Request is executed against primary
    - Request is modified (version incremented) so it can be sent to replicas
    - Engine's translog is fsync'd if necessary (failing, and throwing an exception)
    - Modified request is retried against new primary

    This change ignores the exception where the engine is already closed
    when syncing the translog (similar to how we ignore exceptions when
    refreshing the shard if the ?refresh=true flag is used).

commit 4ac68bb1658688550ced0c4f479dee6d8b617777
Author: Shay Banon <kimchy@gmail.com>
Date:   Tue Jul 21 22:37:29 2015 +0200

    Replica allocator unit tests
    First batch of unit tests to verify the behavior of replica allocator

commit 94609fc5943c8d85adc751b553847ab4cebe58a3
Author: Jason Tedor <jason@tedor.me>
Date:   Tue Jul 21 14:04:46 2015 -0400

    Correctly list blobs in Azure storage to prevent snapshot corruption and do not unnecessarily duplicate Lucene segments in Azure Storage

    This commit addresses an issue that was leading to snapshot corruption for snapshots stored as blobs in Azure Storage.

    The underlying issue is that in cases when multiple snapshots of an index were taken and persisted into Azure Storage, snapshots subsequent
    to the first would repeatedly overwrite the snapshot files. This issue does render useless all snapshots except the final snapshot.

    The root cause of this is due to String concatenation involving null. In particular, to list all of the blobs in a snapshot directory in
    Azure the code would use the method listBlobsByPrefix where the prefix is null. In the listBlobsByPrefix method, the path keyPath + prefix
    is constructed. However, per 5.1.11, 5.4 and 15.18.1 of the Java Language Specification, the reference null is first converted to the string
    "null" before performing the concatenation. This leads to no blobs being returned and therefore the snapshot mechanism would operate as if
    it were writing the first snapshot of the index. The fix is simply to check if prefix is null and handle the concatenation accordingly.

    Upon fixing this issue so that subsequent snapshots would no longer overwrite earlier snapshots, it was discovered that the snapshot metadata
    returned by the listBlobsByPrefix method was not sufficient for the snapshot layer to detect whether or not the Lucene segments had already
    been copied to the Azure storage layer in an earlier snapshot. This led the snapshot layer to unnecessarily duplicate these Lucene segments
    in Azure Storage.

    The root cause of this is due to known behavior in the CloudBlobContainer.getBlockBlobReference method in the Azure API. Namely, this method
    does not fetch blob attributes from Azure. As such, the lengths of all the blobs appeared to the snapshot layer to be of length zero and
    therefore they would compare as not equal to any new blobs that the snapshot layer is going to persist. To remediate this, the method
    CloudBlockBlob.downloadAttributes must be invoked. This will fetch the attributes from Azure Storage so that a proper comparison of the
    blobs can be performed.

    Closes elastic/elasticsearch-cloud-azure#51, closes elastic/elasticsearch-cloud-azure#99

commit cf1d481ce5dda0a45805e42f3b2e0e1e5d028b9e
Author: Lee Hinman <lee@writequit.org>
Date:   Mon Jul 20 08:41:55 2015 -0600

    Unit tests for `nodesAndVersions` on shared filesystems

    With the `recover_on_any_node` setting, these unit tests check that the
    correct node list and versions are returned.

commit 3c27cc32395c3624f7c794904d9ea4faf2eccbfb
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 14:15:59 2015 -0400

    don't fail junit4 integration tests if there are no tests.

    instead fail the failsafe plugin, which means the external cluster will still get shut down

commit 95d2756c5a8c21a157fa844273fc83dfa3c00aea
Author: Alexander Reelsen <alexander@reelsen.net>
Date:   Tue Jul 21 17:16:53 2015 +0200

    Testing: Fix help displaying tests under windows

    The help files are using a unix based file separator, where as
    the test relies on the help being based on the file system separator.

    This commit fixes the test to remove all `\r` characters before
    comparing strings.

    The test has also been moved into its own CliToolTestCase, as it does
    not need to be an integration test.

commit 944f06ea36bd836f007f8eaade8f571d6140aad9
Author: Clinton Gormley <clint@traveljury.com>
Date:   Tue Jul 21 18:04:52 2015 +0200

    Refactored check_license_and_sha.pl to accept a license dir and package path

    In preparation for the move to building the core zip, tar.gz, rpm, and deb as separate modules, refactored check_license_and_sha.pl to:

    * accept a license dir and path to the package to check on the command line
    * to be able to extract zip, tar.gz, deb, and rpm
    * all packages except rpm will work on Windows

commit 2585431e8dfa5c82a2cc5b304cd03eee9bed7a4c
Author: Chris Earle <pickypg@users.noreply.github.com>
Date:   Tue Jul 21 08:35:28 2015 -0700

    Updating breaking changes

    - field names cannot be mapped with `.` in them
    - fixed asciidoc issue where the list was not recognized as a list

commit de299b9d3f4615b12e2226a1e2eff5a38ecaf15f
Author: Shay Banon <kimchy@gmail.com>
Date:   Tue Jul 21 13:27:52 2015 +0200

    Replace primaryPostAllocated flag and use UnassignedInfo
    There is no need to maintain additional state as to if a primary was allocated post api creation on the index routing table, we hold all this information already in the UnassignedInfo class.
    closes #12374

commit 43080bff40f60bedce5bdbc92df302f73aeb9cae
Author: Alexander Reelsen <alexander@reelsen.net>
Date:   Tue Jul 21 15:45:05 2015 +0200

    PluginManager: Fix bin/plugin calls in scripts/bats test

    The release and smoke test python scripts used to install
    plugins in the old fashion.

    Also the BATS testing suite installed/removed plugins in that
    way. Here the marvel tests have been removed, as marvel currently
    does not work with the master branch.

    In addition documentation has been updated as well, where it was
    still missing.

commit b81ccba48993bc13c7678e6d979fd96998499233
Author: Boaz Leskes <b.leskes@gmail.com>
Date:   Tue Jul 21 11:37:50 2015 +0200

    Discovery: make sure NodeJoinController.ElectionCallback is always called from the update cluster state thread

    This is important for correct handling of the joining thread. This causes assertions to trip in our test runs. See http://build-us-00.elastic.co/job/es_g1gc_master_metal/11653/ as an example

    Closes #12372

commit 331853790bf29e34fb248ebc4c1ba585b44f5cab
Author: Boaz Leskes <b.leskes@gmail.com>
Date:   Tue Jul 21 15:54:36 2015 +0200

    Remove left over no commit from TransportReplicationAction

    It asks to double check thread pool rejection. I did and don't see problems with it.

commit e5724931bbc1603e37faa977af4235507f4811f5
Author: Alexander Reelsen <alexander@reelsen.net>
Date:   Tue Jul 21 15:31:57 2015 +0200

    CliTool: Various PluginManager fixes

    The new plugin manager parser was not called correctly in the scripts.
    In addition the plugin manager now creates a plugins/ directory in case
    it does not exist.

    Also the integration tests called the plugin manager in the deprecated way.

commit 7a815a370f83ff12ffb12717ac2fe62571311279
Author: Alexander Reelsen <alexander@reelsen.net>
Date:   Tue Jul 21 13:54:18 2015 +0200

    CLITool: Port PluginManager to use CLITool

    In order to unify the handling and reuse the CLITool infrastructure
    the plugin manager should make use of this as well.

    This obsolets the -i and --install options but requires the user
    to use `install` as the first argument of the CLI.

    This is basically just a port of the existing functionality, which
    is also the reason why this is not a refactoring of the plugin manager,
    which will come in a separate commit.

commit 7f171eba7b71ac5682a355684b6da703ffbfccc7
Author: Martijn van Groningen <martijn.v.groningen@gmail.com>
Date:   Tue Jul 21 10:44:21 2015 +0200

    Remove custom execute local logic in TransportSingleShardAction and TransportInstanceSingleOperationAction and rely on transport service to execute locally. (forking thread etc.)

    Change TransportInstanceSingleOperationAction to have shardActionHandler to, so we can execute locally without endless spinning.

commit 0f38e3eca6b570f74b552e70b4673f47934442e1
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 17:36:12 2015 -0700

    More readMetadata tests and pickiness

commit 880b47281bd69bd37807e8252934321b089c9f8e
Author: Ryan Ernst <ryan@iernst.net>
Date:   Tue Jul 21 14:42:09 2015 -0700

    Started unit tests for plugin service

commit cd7c8ddd7b8c4f3457824b493bffb19c156c7899
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 07:21:07 2015 -0400

    fix tests

commit 673454f0b14f072f66ed70e32110fae4f7aad642
Author: Robert Muir <rmuir@apache.org>
Date:   Tue Jul 21 06:58:25 2015 -0400

    refactor pluginservice
2015-07-22 10:45:45 -04:00
Jason Tedor 96c245c190 Merge pull request #12380 from jasontedor/fix/elasticsearch-cloud-azure-51
Correctly list blobs in Azure Storage to prevent snapshot corruption and do not unnecessarily duplicate Lucene segments in Azure Storage
2015-07-21 16:47:04 -04:00
Jason Tedor 0b8b147a74 Correctly list blobs in Azure storage to prevent snapshot corruption and do not unnecessarily duplicate Lucene segments in Azure Storage
This commit addresses an issue that was leading to snapshot corruption for snapshots stored as blobs in Azure Storage.

The underlying issue is that in cases when multiple snapshots of an index were taken and persisted into Azure Storage, snapshots subsequent
to the first would repeatedly overwrite the snapshot files. This issue does render useless all snapshots except the final snapshot.

The root cause of this is due to String concatenation involving null. In particular, to list all of the blobs in a snapshot directory in
Azure the code would use the method listBlobsByPrefix where the prefix is null. In the listBlobsByPrefix method, the path keyPath + prefix
is constructed. However, per 5.1.11, 5.4 and 15.18.1 of the Java Language Specification, the reference null is first converted to the string
"null" before performing the concatenation. This leads to no blobs being returned and therefore the snapshot mechanism would operate as if
it were writing the first snapshot of the index. The fix is simply to check if prefix is null and handle the concatenation accordingly.

Upon fixing this issue so that subsequent snapshots would no longer overwrite earlier snapshots, it was discovered that the snapshot metadata
returned by the listBlobsByPrefix method was not sufficient for the snapshot layer to detect whether or not the Lucene segments had already
been copied to the Azure storage layer in an earlier snapshot. This led the snapshot layer to unnecessarily duplicate these Lucene segments
in Azure Storage.

The root cause of this is due to known behavior in the CloudBlobContainer.getBlockBlobReference method in the Azure API. Namely, this method
does not fetch blob attributes from Azure. As such, the lengths of all the blobs appeared to the snapshot layer to be of length zero and
therefore they would compare as not equal to any new blobs that the snapshot layer is going to persist. To remediate this, the method
CloudBlockBlob.downloadAttributes must be invoked. This will fetch the attributes from Azure Storage so that a proper comparison of the
blobs can be performed.

Closes elastic/elasticsearch-cloud-azure#51, closes elastic/elasticsearch-cloud-azure#99
2015-07-21 16:33:33 -04:00