Describe the bug
Deploying a new job, then pulling logs via the CLI results in a panic (SIGSEGV).

To Reproduce

1. odin deploy -f test.job.yaml
2. odin log -i {job_id}

vagrant@vagrant:~/odin$ odin log -i dea194794589
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x40 pc=0x79c764]

goroutine

This could be example that uses these supported syntax and APIs:

https://github.com/couler-proj/couler/tree/d34a690/couler/core/syntax

To repro:

myFunc <- function(a, b, c) {
    return(a + 2*(floor(b/c)))
}

myModule <- CustomFunctionModule$new(name = "myFunc"
                                     , fun = myFunc)

myModule$startExecution(list(a = 1, b = 2, c=0.3))
myModule$getOutput()

Output:

[1] "*UpDraft* myFunc took 7.70092e-05 seconds to complete"
[1] "*UpDraft* myFunc took 7.70092e-05 seconds