Add CHROME_VERSION envvar for later buildpacks

[fkztw]

Reason why I send this PR

Send this PR because lots of https://github.com/heroku/heroku-buildpack-chromedriver users (including me) encountered the chromedirver and Chrome version mismatch problem (This version of ChromeDriver only supports Chrome version XX) so often and some of these users even create issues in here:

• This version of ChromeDriver only supports Chrome version 85 heroku-buildpack-chromedriver#27
• Wrong version is downloaded heroku-buildpack-chromedriver#26
  • Buildpack installs chromium-chromedriver when it shouldn't #94
• google chrome no longer running heroku-buildpack-chromedriver#21
• How to disable auto-update? #82 (potentially related)
• Failures due to "This version of ChromeDriver only supports Chrome version 81" #86

Although heroku-buildpack-chromedriver has a feature which you can set the CHROMEDIRVER_VERSION config var in Heroku dashboard to make it install the specific version of chromedriver.
But, It's annoying that if I push my code to Heroku once a while. It will download the new version Chrome and new version chromedriver then this problem shows again. (Same for new users.)
I have to login to the console, check the version of Chrome, modify the CHROMEDIRVER_VERSION config var and make Heroku rebuild my app again to solve this problem.

So, I came out with a idea:

"What if heroku-buildpack-chromedriver can install the same version of chromedriver for the Chrome installed by heroku-buildpack-google-chrome automatically?"

At first, I was trying to solve this problem in heroku-buildpack-chromedriver without sending PR to this upstream repo.
But, after spent some time on digging out the code, realizing how it works and testing on my own Heroku app.
I found out I cannot get the version of Chrome installed by heroku-buildpack-google-chrome.
Although it did export PATH="$BUILD_DIR/.apt/usr/bin:$PATH" for later buildpacks in

heroku-buildpack-google-chrome/bin/compile

Lines 156 to 165 in e85ed96

	export PATH="$BUILD_DIR/.apt/usr/bin:$PATH"
	export LD_LIBRARY_PATH="$BUILD_DIR/.apt/usr/lib/x86_64-linux-gnu:$BUILD_DIR/.apt/usr/lib/i386-linux-gnu:$BUILD_DIR/.apt/usr/lib:$LD_LIBRARY_PATH"
	export LIBRARY_PATH="$BUILD_DIR/.apt/usr/lib/x86_64-linux-gnu:$BUILD_DIR/.apt/usr/lib/i386-linux-gnu:$BUILD_DIR/.apt/usr/lib:$LIBRARY_PATH"
	export INCLUDE_PATH="$BUILD_DIR/.apt/usr/include:$BUILD_DIR/.apt/usr/include/x86_64-linux-gnu:$INCLUDE_PATH"
	export CPATH="$INCLUDE_PATH"
	export CPPPATH="$INCLUDE_PATH"
	export PKG_CONFIG_PATH="$BUILD_DIR/.apt/usr/lib/x86_64-linux-gnu/pkgconfig:$BUILD_DIR/.apt/usr/lib/i386-linux-gnu/pkgconfig:$BUILD_DIR/.apt/usr/lib/pkgconfig:$PKG_CONFIG_PATH"
	#give environment to later buildpacks
	export | grep -E -e ' (PATH|LD_LIBRARY_PATH|LIBRARY_PATH|INCLUDE_PATH|CPATH|CPPPATH|PKG_CONFIG_PATH)=' > "$LP_DIR/export"

I thought I could easily use google-chrome --version to get it in the heroku-buildpack-chromedriver building process, so I don't need to send a PR to this repo. Since there's a alias
$BUILD_DIR/.apt/usr/bin/google-chrome been created at

heroku-buildpack-google-chrome/bin/compile

Lines 172 to 186 in e85ed96

	BIN_DIR=$BUILD_DIR/.apt/usr/bin
	rm $BIN_DIR/$SHIM
	cat <<EOF >$BIN_DIR/$SHIM
	#!/usr/bin/env bash
	if [ \$1 = "--version" ]; then
	exec \$HOME/.apt/opt/google/$BIN --version
	elif [ \$1 = "--product-version" ]; then
	exec \$HOME/.apt/opt/google/$BIN --product-version
	else
	exec \$HOME/.apt/opt/google/$BIN --headless --no-sandbox --disable-gpu --remote-debugging-port=9222 \$@
	fi
	EOF
	chmod +x $BIN_DIR/$SHIM
	cp $BIN_DIR/$SHIM $BIN_DIR/google-chrome

But, I was wrong. The problem is that alias points to the $HOME. During the building process, all things are still in the $BUILD_DIR, not copied to $HOME yet. So, I got the error message while testing my patch:

/tmp/build_04cb8278/.apt/usr/bin/google-chrome: line 3: /app/.apt/opt/google/chrome/chrome: No such file or directory

I am not sure if late buildpack use the same $BUILD_DIR as the previous buildpack, But even if so, I had to call $BUILD_DIR/.apt/opt/google/$BIN --product-version to get the version of Chrome. The problem is $BIN is decided by the $channel in this repo:

heroku-buildpack-google-chrome/bin/compile

Lines 41 to 58 in e85ed96

	# Setup bin and shim locations for desired channel, and detect invalid channels
	case "$channel" in
	"stable")
	BIN=chrome/chrome
	SHIM=google-chrome-stable
	;;
	"beta")
	BIN=chrome-beta/chrome
	SHIM=google-chrome-beta
	;;
	"unstable")
	BIN=chrome-unstable/chrome
	SHIM=google-chrome-unstable
	;;
	*)
	error "GOOGLE_CHROME_CHANNEL must be 'stable', 'beta', or 'unstable', not '$channel'."
	;;
	esac

I don't think it's a good idea to find all the possible executables in a downstream repo. So, that's the reason why I am here to send this PR.

---

Detail

So, I have to get the CRHOME_VERSION from $BUILD_DIR/.apt/opt/google/$BIN --product-version which is the absolute path of the downloaded Chrome.
Export it for the later buildpacks, which is heroku-buildpack-chromedriver here. So, it will know what version of chromedriver to download. (Of course, Need to modify the code of heroku-buildpack-chromedirver.)

---

Review

After using my patches of these two repos to build my Heroku App:

• https://github.com/M157q/heroku-buildpack-google-chrome/tree/add-chrome_version-envvar-for-later-buildpacks
• https://github.com/M157q/heroku-buildpack-chromedriver/tree/find-same-version-as-chrome

It works like a charm on Heroku-18.
Here's a part of the build log:

The version of Chrome installed by heroku-buildpack-google-chrome And the version of chromedirver installed by patched heroku-buildpack-chromedriver (app name erased for safety reason):

---

Further

If this PR could be merged, I think it can also solve another PR: #78

Hope this PR could be merged.
Any further discussions are welcome.
Thank you and appreciate your time for reading this long PR description.

[CrazybutSolid]

+1.

Chrome 85 broke my app. Need to find a way to stick with Chrome 84!

[fkztw]

@CrazybutSolid This PR cannot make you stick with Chrome 84. It will still download the latest version of Chrome from https://dl.google.com/linux/direct/google-chrome-${channel}_current_amd64.deb

[kandluis]

+1

[CrazybutSolid]

@CrazybutSolid This PR cannot make you stick with Chrome 84. It will still download the latest version of Chrome from https://dl.google.com/linux/direct/google-chrome-${channel}_current_amd64.deb

What can I do make it stick to Chrome 84. I still haven't been able to stabilize it

[arsandov]

I think this is useful! Our build just got broke due the new Chrome 93.

[xyNNN]

What's the state of this pull request?

[edmorley]

Hi! Sorry for the delayed reply. This buildpack has been deprecated in favour of the newer (and hopefully more robust) Chrome for Testing buildpack:
https://blog.heroku.com/improved-browser-testing-on-heroku-with-chrome
https://github.com/heroku/heroku-buildpack-chrome-for-testing

As such, I'm closing this out.