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https://issues.apache.org/jira/browse/TINKERPOP-2044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16632520#comment-16632520
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ASF GitHub Bot commented on TINKERPOP-2044:
-------------------------------------------
GitHub user spmallette opened a pull request:
https://github.com/apache/tinkerpop/pull/943
TINKERPOP-2044 Configurable traversal to validate host connectivity.
https://issues.apache.org/jira/browse/TINKERPOP-2044
The user can now configure the script used to validate the operations of
the remote.
```text
Cluster cluster = Cluster.build().validationRequest("g.inject()").create()
```
Builds with `mvn clean install -pl gremlin-driver && mvn verify -pl
gremlin-server -DskipIntegrationTests=false`
VOTE +1
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/apache/tinkerpop TINKERPOP-2044
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/tinkerpop/pull/943.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #943
----
commit bd1760f56a1e70cc49f4129a367c60e748aa54ad
Author: Stephen Mallette <spmva@...>
Date: 2018-09-28T19:54:30Z
TINKERPOP-2044 Configurable traversal to validate host connectivity.
----
> Cannot reconnect to Azure cosmos host that becomes available again
> ------------------------------------------------------------------
>
> Key: TINKERPOP-2044
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2044
> Project: TinkerPop
> Issue Type: Bug
> Components: driver
> Affects Versions: 3.3.3
> Reporter: Dantis P S
> Assignee: stephen mallette
> Priority: Major
>
> If a Azure Cosmos Gremlin host goes down and if it becomes available again,
> the tinkerpop3 java driver cannot reconnect to it.
> Sample code is available at [https://github.com/cancure/tinkerpopcosmos]
>
> These are the steps to reproduce -
> 1) Start the application after providing proper connection details in
> remote.yaml file.
> 2) Call the end point POST [http://localhost:8080/query.] Pass a valid
> gremlin query as HTTP body E.g. g.V(1).id()
> 3) Disconnect computer from internet.
> 4) Do step 2.
> 5) Reconnect computer to the internet.
> 6) Do step 2.
> Any query executed from this point onwards gets the error -
> "java.lang.RuntimeException: java.util.concurrent.TimeoutException: Timed out
> while waiting for an available host - check the client configuration and
> connectivity to the server if this message persists".
>
> The issue seems to be coming from
> org.apache.tinkerpop.gremlin.driver.ConnectionPool.java. In line #403, the
> gremlin query used for ping message is '' (Empty string in single quotes).
> final RequestMessage ping =
> RequestMessage.build(Tokens.OPS_EVAL).add(Tokens.ARGS_GREMLIN, "''").create();
>
> Cosmos server returns an error saying that the gremlin query's grammar is
> incorrect. Because of this error the rest of the lines of the method does not
> get executed.
>
> Fix will be to use a gremlin query which is valid for all supported graph DBs.
>
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