Document working in here

README.md

@@ -11,6 +11,58 @@ And so I'm going the other way; Bazel in a monorepo with subprojects so I'm able
 - [Flowmetal](projects/flowmetal)
 - [Lilith](projects/lilith)
 
+## Hacking (Ubuntu)
+
+### Step 1 - Install bazel
+
+As usual, Ubuntu's packaging of the Bazel bootstrap script is ... considerably stale.
+Add the upstream Bazel ppa so we can get reasonably fresh builds.
+
+``` sh
+sudo apt install apt-transport-https curl gnupg
+curl -fsSL https://bazel.build/bazel-release.pub.gpg | gpg --dearmor > bazel.gpg
+sudo mv bazel.gpg /etc/apt/trusted.gpg.d/
+echo "deb [arch=amd64] https://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel.list
+```
+
+### Step 2 - Create a canonical `python`
+
+Bazel, sadly, expects that a platform `python` exists for things.
+Due to Bazel's plugins model, changing this is miserable.
+So just create one.
+
+``` sh
+if ! `which python > /dev/null`; then
+  sudo ln -s `which python3` /usr/bin/python
+fi
+```
+
+### Step 3 - Non-hermetic build deps
+
+The way that Bazel's Python toolchain(s) work is that ultimately they go out to the non-hermetic platform.
+So, in order to be able to use the good tools we have to have some things on the host filesystem.
+
+``` sh
+if [[ "$(sqlite3 --version | awk -F'.' '/^3/ {print $2; exit}')" -lt 35 ]]; then
+  echo "SQLite 3.35.0 or later  (select ... returning support) required"
+  exit 1
+fi
+
+sudo apt install \
+  python3-setuptools \
+  postgresql libpq-dev \
+  sqlite3 libsqlite3-dev
+```
+
+### Working in source
+
+`source activate.sh` is the key.
+It automates a number of tasks -
+1. Building a virtualenv
+2. Synchronizing the virtualenv from the requirements.txt
+3. Updating the virtualenv with all project paths
+4. Activating that virtualenv
+
 ## License
 
 Copyright Reid 'arrdem' McKenzie, 4/8/2021.

activate.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+mkvirtualenv source
+
+workon source
+
+pip install -r tools/python/requirements.txt
+
+for d in $(find . -type d -path "*/src/python"); do
+    d="$(realpath "${d}")"
+    echo "Adding subproject ${d}"
+    add2virtualenv "${d}"
+done