Error when running with Redis Backend

[samudurand]

Describe the bug
Running Julie when using the RedisBackend results in the following error:

java.lang.IllegalArgumentException: argument "content" is null
	at com.fasterxml.jackson.databind.ObjectMapper._assertNotNull(ObjectMapper.java:4757)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:35[15](https://github.com/mobimeo/infrastructure-monorepo/runs/5408337681?check_suite_focus=true#step:4:15))
	at com.purbon.kafka.topology.utils.JSON.toObject(JSON.java:53)
	at com.purbon.kafka.topology.backend.RedisBackend.load(RedisBackend.java:53)
	at com.purbon.kafka.topology.BackendController.load(BackendController.java:103)
	at com.purbon.kafka.topology.ExecutionPlan.init(ExecutionPlan.java:75)
	at com.purbon.kafka.topology.JulieOps.run(JulieOps.java:232)
	at com.purbon.kafka.topology.JulieOps.run(JulieOps.java:268)
	at com.purbon.kafka.topology.CommandLineInterface.processTopology(CommandLineInterface.java:212)
	at com.purbon.kafka.topology.CommandLineInterface.run(CommandLineInterface.java:[16](https://github.com/mobimeo/infrastructure-monorepo/runs/5408337681?check_suite_focus=true#step:4:16)1)
	at com.purbon.kafka.topology.CommandLineInterface.main(CommandLineInterface.java:147)

To Reproduce
Steps to reproduce the behavior:

1. Configure Julie with a Redis backend'

topology.state.cluster.enabled = true
topology.builder.state.processor.class = com.purbon.kafka.topology.backend.RedisBackend
topology.builder.redis.host = myhost
topology.builder.redis.port = 6379

2. Run Julie in dry run mode for the first time (no prior successful execution: julie-ops-cli.sh --brokers ${{ env.KAFKA_TLS_STRING }} --clientConfig config.properties --dryRun --topology topologies/${{ matrix.topology_file }}

Expected behavior
Julie should display the planned changes

Possible reason
I have looked into the code and this section in particular in the Redis backend looks like it would never work on the initial run, since the Redis value would be nil the first time.

String content = jedis.get(JULIE_OPS_STATE);
return (BackendState) JSON.toObject(content, BackendState.class);

What I want to know
Is it an expected behaviour because I am missing something in my configuration ? Or is it a bug with a workaround ?

[purbon]

should be fix with #462, stupid error of manual 101 sorry for that. I have included proper test to make sure it does not happen again

[samudurand]

Nice ! Thanks for that. I figured out a workaround by storing the file manually between builds in S3 but this is a much better solution.