Hi,
We have seen a strange problem on NiFi 1.4.0 where custom processors could
suddenly not be started, because of incompatibility with custom services:
2018-03-02 13:40:35,490 ERROR [main] o.apache.nifi.controller.FlowController
Unable to start …[id=5d57d39a-015c-1000-ffff-ffffd654d90b] due to
java.lang.IllegalStateException: Processor … is not in a valid state due to …
is invalid because … - 1.4-SNAPSHOT from … is not compatible with … -
1.4-SNAPSHOT …]
It seems that the root cause was related to:
2018-03-02 13:39:55,086 WARN [main] org.apache.nifi.nar.NarClassLoaders While
loading …:…:1.5-SNAPSHOT' unable to locate exact NAR dependency
'…:…:1.4-20180302.111133-16'. Only found one possible match …:….:1.4-SNAPSHOT'.
Continuing...
It turned out that our various custom NARs were built on different built
agents.
Maven has the (ugly) behaviour that when a snapshot version is present in the
local repository after local build, the version number will be e.g.
1.4-SNAPSHOT. However if it is downloaded from a remote repository, the version
number includes a timestamp such as 1.4-20180302.111133-16.
So the manifest of the depending NARs contained:
Nar-Dependency-Version: 1.4-20180302.111133-16
while the other NAR file declared:
Nar-Version: 1.4-SNAPSHOT
Not sure if NiFi 1.5 would behave differently when loading such NAR files, but
I would recommend to anyway fix the NiFi Maven Plugin:
https://github.com/apache/nifi-maven/blob/master/src/main/java/org/apache/nifi/NarMojo.java
Replace line 705:
narDependency = new NarDependency(artifact.getGroupId(),
artifact.getArtifactId(), artifact.getVersion());
with:
narDependency = new NarDependency(artifact.getGroupId(),
artifact.getArtifactId(), artifact.getBaseVersion());
Explanation: artifact.getBaseVersion() will always consistenly return
-SNAPSHOT, even in case the artifact was a timestamped snapshot downloaded from
a remote repo.
Thanks
Arne
