Nerd Snipe - 2 Apps, 1 Extension

I’m working on a project for Lyft that will bring in a new app extension to both our passenger and driver apps. The functionality between both apps is going to be identical so sharing code should be maximized. I am trying to figure out how to get it working to make just a single extension that can be used on both apps. This is more difficult than you might imagine, because extensions can be fiddly. They need to share the same version and build strings, and building in Xcode revealed this hidden gem:

Embedded binary's bundle identifier is not prefixed with the parent app's bundle identifier.

Ugh. This begged the question of how I could possibly get it to work. Off to chase a snipe. Let’s start with a sample project, shall we?

I’m no shell script wizard, but it seemed that a run script build phase should do the trick. It needs to run in the host app prior to anything else happening. This means it’s the second build phase (dependencies always need to be built first). Here’s what I came up with:

#! /bin/sh

APPEX_DIR=$BUILT_PRODUCTS_DIR/SharedExtension.appex
INFO_PLIST=$APPEX_DIR/Info.plist
suffix=sharedextension

if [ "$IS_EMPLOYEE" = YES ] ; then
bundleID=io.taphouse.EmployeeApp.$suffix
shortVersion=$VERSION_EMPLOYEE
version=$VERSION_EMPLOYEE.$BUILD_NUMBER_EMPLOYEE
else
bundleID=io.taphouse.CustomerApp.$suffix
shortVersion=$VERSION_CUSTOMER
version=$VERSION_CUSTOMER.$BUILD_NUMBER_CUSTOMER
fi

plutil -replace CFBundleIdentifier -string "$bundleID" $INFO_PLIST
plutil -replace CFBundleShortVersionString -string "$shortVersion" $INFO_PLIST
plutil -replace CFBundleVersion -string "$version" $INFO_PLIST

I’ve extracted out the short version and build values as build settings in each main app target and those get funneled into the script. In this sample I’ve hard-coded each app’s bundle ID to prefix the extension, but at Lyft these are build settings as well. (Pro-tip: make good use of xcconfig files because editing this stuff in Xcode is a huge pain, not to mention the possible merge conflicts that could arise in your project file.)

I’ve got a build setting in one of my apps indicating what kind of app it is (in this case that is the IS_EMPLOYEE setting). Checking that will tell me the environment the script is running in. I setup 3 variables for each app and replace their values in the extension’s already built Info.plist file. This is important, because it’s too late to change the file in my source directory.

So now I’ve got an Info.plist file with all the proper values. Each app will build and run in the simulator. 🎉!

But we don’t write apps for the simulator. We write them for phones. Let’s give that a shot.

0x16b257000 +MICodeSigningVerifier _validateSignatureAndCopyInfoForURL:withOptions:error:: 147: Failed to verify code signature of /private/var/installd/Library/Caches/com.apple.mobile.installd.staging/temp.KCRuNY/extracted/EmployeeApp.app/PlugIns/SharedExtension.appex : 0xe8008001 (An unknown error has occurred.)

Dang. Looking at the build steps for my extension reveals that there’s a code signature step at the very end and changing the Info.plist afterwards seems to break that signature. So how do we get this done?

Well, I don’t know. My best guess is that I might need to figure out how to re-sign the extension after manipulating its Info.plist. Is this possible? Reasonable to do?

What I’ll probably wind up doing is have individual extensions (one for each app) and a shared framework that backs each. I think it will be easier to get going and more resilient to changes in tooling in the future.

Unless you’ve got a way for me to get this done… 🙂

Finny Turns 2

2 years ago yesterday, I was unable to attend Xcoders. I got a frantic call from Emily that her water broke, and I got a ride to the hospital from a good buddy. 24 hours later Finnian was born.

Today he turns 2. It’s hard to believe how big he’s getting. Watching him grow from newborn to our floppy haired jolly boy has been a real blessing. Happy birthday, buddy!

This is My New Site; It Looks Like The Old Site

I have launched my new website. If you’ve been around here before you might not notice anything different (if you’re a new reader – welcome! 👋). But I assure you, it’s different.

I was running my site on Ghost. And while it was great for me for the last few years I found it lacking lately (mostly I want to combine microblogging and full-length blogging). So I decided to build my own engine.

I call it Maverick, and my ambitions for this project are pretty lofty. It’s not a finished product yet; far from it. But I realized that it was close enough to replace Ghost that I should just pull the trigger. Real artists ship, after all. In fact, this is the first thing I’ve shipped on my own since Scorebook back in November, 2014.

Maverick is powered by Vapor, which is a web framework written in Swift. This appealed to me on a few levels but the main one is that I already know Swift since I’m an iOS developer by trade. Not learning a whole new language is a big win for me (as I’ll explain in later posts there were several other things I had to learn to get here).

I started writing the intro post which went into some technical detail but realized that maybe I’d gone too far after 1100 words. So I’m going to go a different route and break things up into different posts. I wanted to get this inaugural post out there to commemorate the occasion.

If you’re curious about Maverick, it’s fully open source. Things are a little confusing, but there are 2 repos: the first is for the actual application, and the second is for my website. I’ll leave you with links to the two repos. Cheers!

Proxying Vapor 3 Using nginx and Docker

Vapor is a framework for running server side code, all built in Swift. There’s a great post by bygri about how to build a Vapor app using Docker. If any of what I’ve just said is confusing, I highly recommend reading that post before getting started here.

During my building of a couple of Vapor apps, I’ve found getting the sites running while hitting localhost:8080 to be really easy. The hard part is putting that site behind a domain locally and even more, getting it deployed to a server. So I’m going to put a huge disclaimer here: I’m no expert in nginx or Docker. I’ve been able to piece things together using web searches and a lot of conversation in the Vapor Discord room. There’s a great channel for Docker specifically, where I’ve been hugely helped by @bygri. He’s good people.

This post’s goal is purely to show how I got my Vapor app - which worked in development - deployed to production and successfully proxied by nginx. There will be a few extra bits I learned along the way as well (just to sweeten the deal for you).

My initial thought process was this:

  1. Everything for my web app lives inside of the git repository.
  2. I have a script to run for local development
  3. When it’s time to deploy, I clone the repo to my server, and run a script to boot it all up there.

Turns out I was a bit mistaken. If you read through the post I linked at the top, you’ll notice that he has separate Dockerfiles for development and production. I skipped over that part, much to my initial peril (so don’t do that).

What I did was create a repository on the Docker Hub which would hold a named, built image. That image is built with the following Dockerfile:

# Build image
FROM swift:4.1 as builder
RUN apt-get -qq update && apt-get -q -y install \
  && rm -r /var/lib/apt/lists/*
WORKDIR /app
COPY . .
RUN mkdir -p /build/lib && cp -R /usr/lib/swift/linux/*.so /build/lib
RUN swift build -c release && mv `swift build -c release --show-bin-path` /build/bin

# Production image
FROM ubuntu:16.04
RUN apt-get -qq update && apt-get install -y \
  libicu55 libxml2 libbsd0 libcurl3 libatomic1 \
  tzdata \
  && rm -r /var/lib/apt/lists/*
WORKDIR /app
COPY --from=builder /build/bin/Run .
COPY --from=builder /build/lib/* /usr/lib/
COPY Resources/ ./Resources/
EXPOSE 8080
ENTRYPOINT ./Run serve -e prod -b 0.0.0.0

If you have discerning eyes you’ll notice that this Dockerfile is almost exactly the same as the one in the post  I referenced above (go read it and come back if you didn’t earlier). That’s because I copied it from him 😊. The one addition I had to make was COPY Resources/ ./Resources. What this does is copies the Resources directory from my local drive and into the Docker image.

I was initially skeptical that I needed the EXPOSE directive since nginx would proxy over there by default, but I’ve confirmed that it’s not exposed on my server and this will make for good documentation, so 🤷‍♂️.

I built that image using docker build -t jsorge/taphouse.io. Then I can push the image using docker push jsorge/taphouse.io. These 2 commands will build the image and tag it locally, then push it up to Docker Hub. I highly suggest scripting this stuff (I’m becoming partial to Makefiles to get it all done).

Now let’s flip our environment to the production server. I don’t need much to bring in the Vapor app since it’s already built and hosted. I just need to reference it and mount the Public folder.

But then comes the fun part. I’ll catch you on the flipside of the compose file:

version: "3.3"
services:
  web:
	image: jsorge/taphouse.io
	volumes:
	  - ./Public:/app/Public
  nginx:
	image: nginx:alpine
	restart: always
	ports:
	  - 80:80
	  - 443:443
	volumes:
	  - ./Public:/home/taphouse/Public
	  - ./nginx/server.conf:/etc/nginx/conf.d/default.conf
	  - ./nginx/logs:/var/log/nginx
	depends_on:
	  - web

Ok, so what’s going on here? We’re grabbing the nginx image from alpine (a trusted provider of nginx). I’m honestly not sure what the restart command does but it showed up on my DuckDuckGo results of examples. But the rest I understand.

ports: I’m exposing ports 80 and 443 to get http and https traffic listened to (the syntax for ports is <external>:<container-internal>). I could pick other internal ports to listen to and update my nginx configs appropriately but didn’t feel like rocking the boat too much. I plan on adding TLS support via letsencrypt but that’s a problem for another day.

volumes: I’m sure people familiar with Docker won’t need this explained (or any of this compose file really) but this part blows my mind a bit. The volumes directive basically puts a link from the local machine to inside the container. The link could be a file or a folder; that part doesn’t matter. So to get the root of my site working in nginx, I mount the Public folder that exists locally on my machine into the container at the specified path. The syntax for this is <local-path>:<container-path>.

I also created the path of nginx/logs on my server, and mounted it as the log directory in the container. This allows me to have the logs from the container persisted to my server volume and easily read them as they come in. This is super cool!

depends_on: This one is pretty cool. It establishes the dependency chain between your containers and starts them up in the proper order to satisfy them. In this case, nginx depends on my Vapor app (called web).

The nginx configuration file is the last link in the chain to get us going. This is what mine looks like:

server {
	server_name taphouse.io;
	listen 80 default_server;

	root /home/taphouse/Public/;

	try_files $uri @proxy;

	location @proxy {
		proxy_pass http://web:8080;
		proxy_pass_header Server;
		proxy_set_header Host $host;
		proxy_set_header X-Real-IP $remote_addr;
		proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
		proxy_pass_header Server;
		proxy_connect_timeout 3s;
		proxy_read_timeout 10s;
	}
}

I got this by finding the suggested configuration for Vapor 2. Curiously this page hasn’t made its way to the Vapor 3 docs but I’m guessing that has something to do with them wanting you to deploy on Vapor Cloud. I’m removing my tinfoil hat now.

As far as nginx configuration files go, this one looks pretty standard. I don’t know the exact ins and outs of what’s going on but the point of note is here: proxy_pass http://web:8080;. Remember how I said earlier that Docker Compose provides its own networking? Well it turns out I can use my Vapor container name as the host and it will resolve everything inside the container network. Super cool!

From here I got these files on the server and ran my make server command (which aliases to docker-compose -f docker-compose-prod.yml up --build -d) and tried hitting http://taphouse.io. It worked! 🤯

The next thing on my list is to get acme.sh working so that TLS is up and running, and I can disable port 80. That’s my current holdup, but when I get that done I’ll be sure to write that up as well.

If I made any grievous errors or you have general feedback, I’d love to hear it. I’m still very green when it comes to Docker, nginx, and server admin stuff in general.

Building a Blog Engine

For the last few months I’ve been thinking about what to do with my blog setup. I experimented a bit with Jekyll but that ended up not really appealing to me. In the consideration of switching platforms I realized I wanted something that would be easy to move (and not be beholden to should the need to move again arise). Markdown text files check that box; but what about images?

How would I move the images I’ve hosted on my own server? Where do they land in the new location? I had no good idea until I stumbled up on textbundles. Textbundles basically wrap up a markdown file and assets folder inside of a directory. Bundles are a very familiar concept for anyone on a Mac; we’ve had them since OS X became a thing.

I first decided to figure out how to make this format work in Jekyll. Would it be a hook I need to build? Where would that go in the pipeline and how does it work? Also, how do I even Ruby?

All of this started to make my new site feel like a distant goal. Learning a new language and framework was kind of daunting. Not that I’m opposed to such things, but I don’t have a ton of extra time available plus it could easily distract me from my goal.

In the meantime I decided to give Vapor a look again. I’d played with v2 last year when trying to rebuild my company website. It was… ok. But Vapor 3 really clicked for me and I could see while writing it how a blog engine could work. So I figured I’d go for it.

Meet Maverick.

As of this writing I’m probably 80% done with the site. In local testing it does exactly what I need it to do on a basic level. Blog post and static page support. Everything served from a textbundle. That’s the easy part.

The hard part now is how to deploy. I’ve got a lot to learn about Docker and TLS. I tried adding TLS to the new Taphouse site and couldn’t get it figured out. But also if I want to make this an easy system for someone else to adapt, how do I do that?

I know that posts should be separated from the engine itself. So the bare repo for new sites should have some script to grab the Maverick app and run it in some container. Since it’s just a self-contained Swift app that should be straightforward enough, right?

All of this consideration kind of has me paralyzed at the moment. I was hoping to punt on deployment a bit until I got Ulysses and Micro.blog support wrapped up but they seem to depend on TLS connections, and that brings me back to getting things deployed.

So that’s where I’m at. I’m super excited about getting Maverick onto my server and running it full time. But getting there means jumping a few more hurdles first.