Github user doanduyhai commented on the issue:
https://github.com/apache/zeppelin/pull/1369
@astroshim @AhyoungRyu it tooks me hours but I have found the root cause of
the issue and it's pretty ugly. Ready to hear ?
1) First issue is we **do not** set the InterpreterSetting `status` and
`errorReason` together. For example here:
https://github.com/apache/zeppelin/blob/master/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterFactory.java#L398
```java
...
setting.setStatus(InterpreterSetting.Status.DOWNLOADING_DEPENDENCIES);
interpreterSettings.put(setting.getId(), setting);
...
```
So here we set the status to `DOWNLOADING_DEPENDENCIES` but the
`errorReason` stills contains the previous value, possible something like
"Cannot download dependency x.y.z ....". That explains why we see
```
...
"status":"DOWNLOADING_DEPENDENCIES",
"errorReason":"Could not find artifact one:two:jar:1.1.1 in central
(http://repo1.maven.org/maven2/)",
...
```
2) Second issue is more serious, it is concurrency issue. We set the status
of the dependency download in a separate thread:
https://github.com/apache/zeppelin/blob/master/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterFactory.java#L400-L433
```java
...
catch (Exception e) {
logger.error(String.format("Error while downloading repos for
interpreter group : %s," +
" go to interpreter setting page click on edit and save
it again to make " +
"this interpreter work properly.",
setting.getGroup()), e);
setting.setErrorReason(e.getLocalizedMessage());
setting.setStatus(InterpreterSetting.Status.ERROR);
...
```
The problem is that the initial status is set to `DOWNLOADING_DEPENDENCIES`
and then the interpreter status is returned by the caller class to the client:
https://github.com/apache/zeppelin/blob/master/zeppelin-server/src/main/java/org/apache/zeppelin/rest/InterpreterRestApi.java#L113-L135
I added extra log message to debug:
```
...
logger.info("************** DEBUG_ZEPPELIN setting status
ERROR");
setting.setStatus(InterpreterSetting.Status.ERROR);
setting.setErrorReason(e.getLocalizedMessage());
...
...
logger.info("************** DEBUG_ZEPPELIN setting debug " +
setting.toDebugString());
return new JsonResponse<>(Status.OK, "", setting).build();
...
```
And below is what is displayed in the logs:
```
INFO [2016-09-07 12:35:26,151] ({qtp240166646-20}
InterpreterRestApi.java[updateSetting]:132) - ************** DEBUG_ZEPPELIN
setting debug DOWNLOADING_DEPENDENCIES :
ERROR [2016-09-07 12:35:26,539] ({Thread-25}
InterpreterFactory.java[run]:433) - Error while downloading repos for
interpreter group : angular, go to interpreter setting page click on edit and
save it again to make this interpreter work properly. : Could not find artifact
one:two:jar:1.1.25 in central (http://repo1.maven.org/maven2/)
org.sonatype.aether.resolution.DependencyResolutionException: Could not
find artifact one:two:jar:1.1.25 in central (http://repo1.maven.org/maven2/)
at
org.sonatype.aether.impl.internal.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:375)
at
org.apache.zeppelin.dep.DependencyResolver.getArtifactsWithDep(DependencyResolver.java:164)
at
org.apache.zeppelin.dep.DependencyResolver.loadFromMvn(DependencyResolver.java:116)
at
org.apache.zeppelin.dep.DependencyResolver.load(DependencyResolver.java:79)
at
org.apache.zeppelin.dep.DependencyResolver.load(DependencyResolver.java:96)
at
org.apache.zeppelin.dep.DependencyResolver.load(DependencyResolver.java:88)
at
org.apache.zeppelin.interpreter.InterpreterFactory$3.run(InterpreterFactory.java:425)
Caused by: org.sonatype.aether.resolution.ArtifactResolutionException:
Could not find artifact one:two:jar:1.1.25 in central
(http://repo1.maven.org/maven2/)
at
org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:537)
at
org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolveArtifacts(DefaultArtifactResolver.java:216)
at
org.sonatype.aether.impl.internal.DefaultRepositorySystem.resolveDependencies(DefaultRepositorySystem.java:358)
... 6 more
Caused by: org.sonatype.aether.transfer.ArtifactNotFoundException: Could
not find artifact one:two:jar:1.1.25 in central (http://repo1.maven.org/maven2/)
at
org.sonatype.aether.connector.wagon.WagonRepositoryConnector$4.wrap(WagonRepositoryConnector.java:971)
at
org.sonatype.aether.connector.wagon.WagonRepositoryConnector$4.wrap(WagonRepositoryConnector.java:966)
at
org.sonatype.aether.connector.wagon.WagonRepositoryConnector$GetTask.flush(WagonRepositoryConnector.java:707)
at
org.sonatype.aether.connector.wagon.WagonRepositoryConnector$GetTask.flush(WagonRepositoryConnector.java:701)
at
org.sonatype.aether.connector.wagon.WagonRepositoryConnector.get(WagonRepositoryConnector.java:452)
at
org.sonatype.aether.impl.internal.DefaultArtifactResolver.resolve(DefaultArtifactResolver.java:456)
... 8 more
INFO [2016-09-07 12:35:26,541] ({Thread-25}
InterpreterFactory.java[run]:437) - ************** DEBUG_ZEPPELIN setting
status ERROR
```
So the `DOWNLOADING_DEPENDENCIES` status is returned to the client
**before** the download error status is set in a **separate** thread.
This issue is indeed already there in the master and it **not** related to
this pull request
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