Support NiFi 1.15

[maltesander]

When implementing up and downgrades (From 1.13.2 -> 1.14.0) i got an error with NiFi.

2021-09-16 20:55:20,146 ERROR [main] org.apache.nifi.NiFi Failure to launch NiFi due to java.lang.IllegalArgumentException: There was an issue decrypting protected properties
java.lang.IllegalArgumentException: There was an issue decrypting protected properties
    at org.apache.nifi.NiFi.initializeProperties(NiFi.java:346)
    at org.apache.nifi.NiFi.convertArgumentsToValidatedNiFiProperties(NiFi.java:314)
    at org.apache.nifi.NiFi.convertArgumentsToValidatedNiFiProperties(NiFi.java:310)
    at org.apache.nifi.NiFi.main(NiFi.java:302)
Caused by: org.apache.nifi.properties.SensitivePropertyProtectionException: Sensitive Properties Key [nifi.sensitive.props.key] not found: See Admin Guide section [Updating the Sensitive Properties Key]
    at org.apache.nifi.properties.NiFiPropertiesLoader.getDefaultProperties(NiFiPropertiesLoader.java:220)
    at org.apache.nifi.properties.NiFiPropertiesLoader.get(NiFiPropertiesLoader.java:209)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.apache.nifi.NiFi.initializeProperties(NiFi.java:341)
    ... 3 common frames omitted

@Jimvin mentioned that they need encryption out of the box.

Needs investigation.

[lfrancke]

Just a heads-up: NiFi 1.15 has been released. As far as I'm concerned the latest version is the only version we need to support at the moment.

[fhennig]

I found the problem. It is only a single property, for which - since 1.14 - no default value is provided anymore and an explicit value needs to be given. The property is the encryption key for sensitive properties in flows. If a user would like to migrate from the 1.13 default key to an explicit key, a script needs to be run: https://nifi.apache.org/docs/nifi-docs/html/administration-guide.html#updating-the-sensitive-properties-key

If there are no sensitive properties to migrate, the new version can simply be used.

I added a hardcoded key. The key should be configurable, but making nifi secure needs more than that, and that's a seperate issue.

[fhennig]

Update:

• We'll get rid of 1.13 entirely and look at it again if we need it.
• The sensitive props key should be loaded from a secret

Nifi doesn't support the loading of the key from an environment variable directly. The official nifi docker image had this problem too, I'll use that as guidance on how to implement a solution