"Creating a simple DAG Driver for Knative"

[NotAnAddictz]

Summary

In current implementation, single execution of go run cmd/loader.go --config cmd/config.json would create an individualFunctionDriver per function and invoke individual functions with a set frequency.
The new implementation would create a new functionsDriver which invoke all the functions sequentially, following the invocation frequency of the first function.

Implementation Notes ⚒️

• Added a new parameter DAGMode in cmd/config.json to toggle DAGMode.
• When DAGMode = true, functionsDriver() in the full list of provided functions and invokes them sequentially in a loop.
• Added a new Node structure to hold function pointers and pointer to the next Node
• Edited parameter in invokeGRPC() to reflect invocation stats for each function.
  

External Dependencies 🍀

• (N/A)

Breaking API Changes ⚠️

• (N/A)

Simply specify none (N/A) if not applicable.

[leokondrashov]

Please elaborate more on the operation of the proposed changes, why, what, how in the PR description. The documentation should also be in the repo docs.

Also, follow instructions from vhive contributing guide and signoff your commits.

[NotAnAddictz]

Have updated the PR description, loader.md document and signed off. Do let me know if there is anything else to update.

[leokondrashov]

Please be more descriptive of how it should be used. Like, you didn't mention the structure of the new file with DAG structure. Moreover, there is no example file. This is important since not everyone would dive into the code to determine the file's structure.

In addition, fix the spellcheck CI (add the word into the wordlist .github/configs/wordlist.txt).

[leokondrashov]

Please remove duplicate code. Also, the line

Added new structs InvocationMetadataDAG to parse in the list of functions into individualDAGDriver()

in the description confused me, that we have some file that has the description of the DAG, while we just invoke all of them one after another. Please fix the wording.

[leokondrashov]

LGTM. @cvetkovic Please review as well.

[cvetkovic]

Can you write a unit test for a trace driver with DAG mode enabled?

[leokondrashov]

LGTM! Thanks for the added test