[docs] Improve lab setup instructions (#3)

lab-testing.md

@@ -1,6 +1,28 @@
 
 # Lab-testing a proxied environment
 
+There are 4 basic things that need to work in a behind-proxy ddev environment:
+
+1. The host needs to be configured to work. Of course if you're already working in a proxied environment you already know how to do this. Typically it's set up in the OS settings, and then the browsers are configured to use the system proxy settings. curl typically respects HTTP_PROXY and HTTPS_PROXY, and wget will respect http_proxy, etc.
+
+2. The docker server needs to be configured via either:
+
+    * The "proxies" section of the Docker Desktop application (on Windows or macOS) or
+    * by creating an `/etc/systemd/system/docker.service.d/http-proxy.conf` file on Linux -
+      [see Docker docs](https://docs.docker.com/config/daemon/systemd/#httphttps-proxy) . This will allow actions like `docker pull` to work correctly using the proxy. See [example http-proxy.conf](http-proxy.conf).
+
+   If you use the first approach, you need to set the "http proxy server" and "https proxy server" to point to your proxy, and add "127.0.0.1" to the proxy bypass settings in Docker Desktop (Settings -> Resources -> Proxies).
+
+   Example:
+
+    * Web Server (HTTP) : `http://proxy:8888`
+    * Secure Web Server (HTTPS) : `http://proxy:8888`
+    * Bypass proxy settings for these hosts & domains: `127.0.0.1`
+
+3. Normally, on Windows and macOS, the settings above will be reflected in ~/.docker/config.json, but if not they can be added there as shown in [Docker docs](https://docs.docker.com/network/proxy/). Again, you need to add the HTTP and HTTPS proxyes, and add ``"noProxy": 127.0.0.1,*.ddev.site`.
+
+4. The [pre.Dockerfile.proxy-support](web-build/pre.Dockerfile.proxy-support) provided by this add-on enables apt support of the proxy.
+
 I used Parallels on macOS for the test lab.
 
 * Created a Parallels VM proxy server with a simple tiny Ubuntu 22.04 server running [tinyproxy](https://tinyproxy.github.io/), which was shockingly simple to install and configure (`apt-get install tinyproxy`), very small configuration changes ([example /etc/tinyproxy/tinyproxy.conf](tinyproxy.conf)). I'll call this machine "proxy".
@@ -11,6 +33,6 @@ I used Parallels on macOS for the test lab.
 * Configured the workstation VM with system-wide proxy settings using the regular Ubuntu network setting GUI (in this case HTTP/HTTPS proxies using proxy.host-only:8888).
 * Configured the Firefox browser on "workstation" to use the system-configured proxy and verified that it could now operate.
 * Verified that curl against internet https locations now worked on the "workstation".
-* Configured the docker server as in step 2 above, and verified that `docker pull ubuntu` now worked on "workstation" using the proxy.
-* Configured the docker client as in step 3 above and verified that proxy setup was now right in the container by `ddev start`, `ddev ssh`, and using curl inside the container against an HTTPS website.
-* Added the .ddev/web-build/Dockerfile from step 4 into the ddev project on the "workstation" and `ddev start`, then `ddev ssh` and `sudo apt-get update` and saw the update happen successfully, all using the proxy.
+* Configured the docker server as in [docker server instructions](https://docs.docker.com/config/daemon/systemd/#httphttps-proxy), and verified that `docker pull ubuntu` now worked on "workstation" using the proxy.
+* Configured the docker client as in [docker client instructions](https://docs.docker.com/network/proxy/#configure-the-docker-client) and verified that proxy setup was now right in the container by `ddev start`, `ddev ssh`, and using curl inside the container against an HTTPS website.
+* `ddev get drud/ddev-proxy-support` installs the [pre.Dockerfile.proxy-support](web-build/pre.Dockerfile.proxy-support) which enables apt support of the proxy.