📝 wrap up tgis docs

Signed-off-by: Joe Runde <[email protected]>

TGIS_README.md

@@ -15,35 +15,70 @@ See a sketch of the commit graph
 ## Contributing changes for vLLM
 
 To contribute vLLM-specific changes, _don't_ base them on the `main` branch in this repo.
+Either contribute to your own fork of vLLM, or create a branch in this repo at the latest `vllm-project/vllm:main` commit.
 
+Open all PRs into [vLLM](https://github.com/vllm-project/vllm)
+
+Once you have opened a PR, follow the steps for [Reconstructing the ephemeral branch](#Ephemeral-branch-building-procedure)
 
 ## Contributing changes specific to the TGIS adapter or IBM delivery
 
+Contributing changes to the TGIS adapter or IBM delivery process is business as usual, 
+make changes on a branch or fork directly from this repo's `main` branch and PR it back in.
+
+Most of the IBM-specific changes in this repo are located in these files/packages:
+- `vllm/tgis_utils` contains many custom implementations of classes required for feature parity with TGIS
+- `vllm/entrypoints/openai/api_server.py` contains changes to parse TGIS specific command line args
+- `vllm/entrypoints/openai/cli_args.py` contains changes to inject TGIS specific command line args
+- `vllm/entrypoints/grpc` is entirely our own package for implementing a grpc server with the TGIS api
+- `proto` contains the TGIS api defs
+- `Dockerfile.ubi` is the UBI-based dockerfile that we build and ship
+- `.github/workflows/build.yml` contains our workflow for building and pushing the UBI-based image
 
 ## Main branch rebasing procedure
 
 Rebasing vllm:main onto ibm:main is pretty straightforward. Assuming you have vllm-project/vllm as the
 `upstream` remote and ibm/vllm as the `origin` remote, one way to do this is:
 ```shell
 # fetch latest ibm main
-git fetch origin/main
+git fetch origin main
 
 # fetch latest vllm main
-git fetch upstream/main
+git fetch upstream main
 git checkout upstream/main
 
-# point a branch there
-git checkout -b upstream-main-sync
-# (or if you already had that branch)
-git branch -f upstream-main-sync HEAD
+# point a branch here
+git branch -D upstream-main-sync || git branch -f upstream-main-sync HEAD
 git checkout upstream-main-sync
 
 # rebase the branch onto ibm main
 git rebase origin/main
+# You may see _many_ warnings about skipping previously applied commits- this is expected
 
-# push push...
-
+# Push to origin/main
+git push origin HEAD:main
 ```
 
 ## Ephemeral branch building procedure
 
+To rebuild the ephemeral branch, we want to squash each pending PR into a commit on top of main.
+
+Assuming this repo is the `origin` remote, this looks something like:
+```shell
+# Fetch latest main
+git fetch origin main
+git checkout origin/main
+
+# Start a new ephemeral branch here
+git branch -D ephemeral || git branch -f ephemeral HEAD
+git checkout ephemeral
+
+# for each ${PR_NUMBER} to squash in:
+git fetch upstream pull/${PR_NUMBER}/head:${PR_NUMBER}
+git merge --squash ${PR_NUMBER}
+# Merge conflicts should be minimal if all PRs are in a mergeable state with vllm:main
+# But pending PRs may create conflicting changes with each other 
+
+# force-push: we're overwriting the `ephemeral` branch
+git push -f origin HEAD:ephemeral
+```