docker-ember

Docker and tooling for using ember-cli in a reproducable way.

Getting Started

Installation

On Linux

Assuming you have docker set up correctly, simply clone this repository and add the bin folder to your path.

git clone https://github.com/madnificent/docker-ember.git
echo "export PATH=\$PATH:`pwd`/docker-ember/bin" >> ~/.bashrc
source ~/.bashrc

On Mac

We suggest to use brew installation scripts to account for specific issues related to docker for mac. See: https://github.com/mu-semtech/homebrew-scripts

Configuration

Picking an Ember Version

The version of docker-ember can be selected for situations where it is not known, otherwise Docker Ember tries to select the correct version.

When visiting a folder which has a Dockerfile with a docker-ember version in it, that version will be used by docker-ember. This allows fluidly switching between projects.

For cases where no version can be found, docker-ember's version can be specified in ~/.config/edi/settings using the VERSION variable.

VERSION="5.3.0"

For one-time use, you can set EDI_EMBER_VERSION to the desired version:

EDI_EMBER_VERSION="5.3.0" edi ember version

Supported versions are the tags available at https://hub.docker.com/r/madnificent/ember/tags/.

Linux configuration with user namespaces (advised)

By default ed* commands run as root in the docker container, this means newly created files will be owned as root as well. To avoid this you can use user namespaces to map the container's root user to your own user. This requires some configuration and can be done with dockerd running as root (default) or as your user (see Linux configuration with rootless docker).

Note

on ubuntu 16.04 your user needs to part of the docker group so that it has access to /var/run/docker.sock

Assuming systemd and access to the id command the following steps should suffice:

1. Create the correct mapping in /etc/subuid and /etc/subgid

   echo "$( whoami ):$(id -u):65536" |  sudo tee -a /etc/subuid
   echo "$( whoami ):$(id -g):65536" |  sudo tee -a /etc/subgid

Note

Using the above user maps mean that the user 0 (root) inside the container are mapped to your user id on the host, the id for every user above that is mapped to your-id + their-id. This means that any containers which run non-root processes could appear to be running as real users on your system. This is unlikely to cause problems unless you have an unusual user configuration.

2. Adjust ExecStart of docker daemon to include --userns-remap=ns1. For systemd you can use the following command:

   systemctl edit docker.service

   The config file might look this:

   [Service]
   ExecStart=
   ExecStart=/usr/bin/dockerd --userns-remap="your-user-name"
   

More information on user namespaces is available in the docker documentation.

Linux configuration with rootless docker

Note

At this point we advise to use user namespaces instead, though if you have some experience with docker then rootless docker is a bright future.

More recent versions of Docker can run in 'rootless' mode, running the docker daemon as a normal user instead of root. When running in this mode, the root user inside containers is always mapped to the host user, so no special subuid or subgid configuration are required. Users inside containers with uids >0 are mapped according to the subuid configuration.

This may cause some issues with other images as some features are not yet supported in rootless.

For more details and configuration steps, see the Docker Rootless documentation as well as any relevant documentation for your distro (e.g. Arch Wiki).

While not directly needed for docker-ember, many projects make use of ports < 1024, which by default require root to allocate. If you wish to continue with this, follow the instructions in the documentation.

Using --add-host is not supported in rootless docker, instead join the desired network and connect directly to the service instead as per Proxy to a Docker Compose service (advanced).

Configuring on Mac

Mac uses a login shell when launching the default terminal app, which slightly changes the desired setup. Sharing the ssh-agent socket currently doesn't work, and thus requires a workaround.

1. Make your shell read .bashrc

   Docker for Mac creates files under the right username automatically. Mac does use a login shell when launching the default terminal app, rather than an interactive shell. These shells don't read the standard ~/.bashrc file, but rather the ~/.bash_profile file. Make sure the following is present in your ~/.bash_profile so ~/.bashrc is always read.

   if [ -f ~/.bashrc ]; then
   source ~/.bashrc
   fi

2. Support the ssh-agent

   The ssh-agent's socket can't be shared with Docker for Mac at the time of writing. A common workaround is to use a Docker container in which a new ssh-agent is ran. We advise the use of the https://github.com/10eTechnology/docker-ssh-agent-forward and have integrated this in the supplied scripts. On mac, this solution is assumed to be installed.

NPM upgrades

It's important to note that since NPM v7 peer dependencies are installed by default when executing npm install. As of v3.27 the docker-ember image contains NPM >= v7.x. Using this version may lead to resolution conflict errors on peer dependencies in existing projects. NPM provides a --legacy-peer-deps flag to make npm install behave like in previous versions, not installing peer dependencies by default. This can help teams to gradually fix the peer dependency version conflicts in their project.

The --legacy-peer-deps flag can be enabled project-wide by adding legacy-peer-deps=true to .npmrc. In that case it's import to copy that file inside your project's Docker build before running npm install.

Example Dockerfile:

FROM madnificent/ember
COPY package.json .
COPY .npmrc .   # <--- this line must be added
RUN npm install

Creating a new app using docker-ember

All commands (except for ember serve which deserves special attention), can be ran through the edi command.

Let’s create a new project:

edi ember new my-edi-app

This will generate a new application. Once all dependencies have been installed, we can move into the application folder, and start the ember server:

cd my-edi-app
eds

You will see the application running. Moving your browser to http://localhost:4200, you will see the ember-welcome-page. Yay! It works \o/

Let’s remove the welcome-page. As instructed, we’ll remove the {{welcome-page}} component from the build. Open your favorite editor, and update the contents of application.hbs to contain the following instead.

<h1>My first edi app</h1>

{{outlet}}

We can generate new routes with the ember application still running. Open a new terminal and open the my-edi-app folder. Then generate the route:

edi ember generate route hello-link

Edit the app/templates/hello-link.hbs template so it contains the following

<p>Hello!  This is some nested content from my first page.  <LinkTo @route='index'>Go back</LinkTo></p>

and add a link to app/templates/application.hbs

<h1>My first edi app</h1>
<p><LinkTo @route='hello-link'>Hello</LinkTo></p>

{{outlet}}

Boom, we have generated files which we can edit. Lastly, we’ll install the ember-cli-sass addon as an example.

edi ember install ember-cli-sass

Now restart eds to ensure the ember server picks up the newly installed addon, remove the old app/styles/app.css and add a background-color to app/styles/app.scss

body {
  background-color: green;
}

Caveats

There are some caveats with the use of edi. First is configuring the ember version. You can switch versions easily by editing a single file. Next is configuring the backend to run against.

• Configuring the ember version You may want to have more than one ember version installed when generating new applications. See Picking an Ember Version

• Linking to a backend Multiple options exist for proxying to a backend. When proxying to localhost use --proxy=http://host/ instead of --proxy=http://localhost/. See Proxy to a local port (default) and [Proxy to a Docker Compose service (advanced)](proxy-to-a-docker-compose-service-(advanced)] for your options.

And you're done! Our EmberJS development has become a lot more consistent and maintainable with the use of edi. We have used it extensively, and have been able to reproduce builds easily in the past year.

This tutorial has been adapted from Aad Versteden's mu.semte.ch article. You can view it here

Experimental features

Some experimental features have been added which optimize the way the Docker daemon is called. These features may behave oddly when developing addons. It may be required to restart certain daemons after using edl, or to disable features when using edl.

Live daemon

Some systems take more time than necessary to spin up a new docker daemon. For these cases, you may choose to keep a daemon alive and send commands to the daemon. Set EDI_USE_EDI_DAEMON to a non-empty string to enable this feature.

Note: You will have to restart the daemon after using edl.

Optimize linked modules

The ember docker links locally developed node modules. Some optimizations are possible in this regard but they break edl.

We mount all available node modules in a consistent way when you use edl. Mounting many volumes may lead to a slow-down on some systems. You may choose to mount only the used linked modules by setting EDI_MOUNT_ONLY_USED_LINKED_MODULES to a non-empty string.

When using older versions of node when developing nested node modules the builds may fail because the right node submodules are not included. This is not the case when the symlinks are removed. Setting both EDI_MOUNT_ONLY_USED_LINKED_MODULES and EDI_MOUNT_USED_NODE_MODULES_WITHOUT_SYMLINKS will mount the used node_modules directly. This may also have a positive performance impact, but we did not run benchmarks.

These optimizations should be disabled when running edl as edl will not be able to find the addons to link.

SSH agent container

We assume you are running an SSH agent container as mentioned earlier. If your application never reaches to the outside world using your ssh key, you may disable this feature.

On Mac, the socket of the native SSH agent can't be shared to the Docker image like we do in Linux. We assume the necessary tooling is available on Mac to share the SSH agent. Should you want to disable this feature, set EDI_SSH_AGENT_CONTAINER to an empty string. If you want to force it to be turned on on Linux, then set it to a non-empty string.

When you disable this option, your locally running socket will be shared. When Docker for Mac starts supporting this feature, that will be the superior option.

---

Usage (how-to)

We have 4 commands, each for a different use-case. Run them at the root of your project.

ed

ed is your default friend. ed helps you install npm & bower dependencies, install new ember dependencies and run any other non-interactive ember command.

# Install a dependency
ed ember install ember-cli-coffeescript
# Install all current node modules
ed npm install
# Install bower components
ed bower install

eds

eds launches the ember server for you.

# No nonsense ember server
eds

Proxy to a local port (default)

If you have a service running on a local port (ie: publishing a port through Docker), you can proxy to that host.

Proxying is done to the special hostname host in this case, which will represent the environment which runs the Docker Ember container.

The Docker Container itself is a mini virtual machine. In this virtual machine, the name localhost indicates that little virtual machine. For example if you're using a Semantic Works architecture backend, published on port 80 in a docker compose project, you can connect your development frontend to it as such:

eds --proxy http://host/

For instance, to proxy to port 8080 of the machine executing the command:

# Proxying to your localhost (note it's been renamed from localhost to host)
eds --proxy=http://host:8080/

Note

The host to proxy to is host in this case, not localhost

Note

This makes use of the default --add-host option which may become optional in the future. For scripting, you may want to run eds --add-host --proxy=http://host:8080/ instead to be explicit.

Proxy to a Docker Compose service (advanced)

Proxying directly to a service in a Docker Compose stack without publishing ports.

Note

The default option --add-host is disabled automatically when using this feature.

Two parts need to be specified: the docker network where the service can be found, and which service to connect to in that network. This does not require publishing a port locally.

# Proxying to a docker network
eds --network=network-name --proxy=http://service:8080

For example if you're using a Semantic Works architecture backend, published on port 80 in a docker compose project called my-project, you could connect your development frontend to it as such:

eds --network=my-project_default --proxy=http://identifier/

Note

This is the only supported method when running Linux configuration with rootless docker

Proxy to an external host

To proxy to an external host use the --proxy option with no extra arguments. Some caveats exists:

• if the backend uses HTTPS, specify the HTTPS url directly: eds --proxy=https://semantic.works/
• with rootless docker you have to disable the docker network wiring using -A option: eds -A --proxy=https://semantic.works/

Serving on a non default port

If port 4200 is already taken, eds can be ran on a different port. Both port (which can be visited in the browser) as well as live-reload-port (for reloading on changes) need to be remapped.

# Serving on a non default port
eds --port=4000 --live-reload-port=64000

edi

edi is the interactive version of ed. It can ask you questions and you can provide interactive answers.

# Generate a route
edi ember generate route epic-win
# Release a new minor version
edi ember release --minor

edl

edl is your friend when developing addons. It provides a replacement for npm link and npm unlink that works in docker-ember.

# Create a global symlink of your addon
cd your-ember-addon
edl
# Use that addon in another project
cd your-ember-project
edl your-ember-addon
# Remove the global symlink of your addon
cd your-ember-addon
edl -u

Note

edl assumes edi is available on your PATH

Building locally

To build locally in any capacity, run the release script using the desired ember-cli version. Example usage: ./release 4.9.2

Several of the files in this repo are a result of building. See the table below for which files to change:

File to change	... for
templates/Dockerfile	for Dockerfile changes
support-scripts	for changes in multiple binaries
templates/bin/*	for changes to specific binaries

---

Explanations

Our ember-cli builds have not been as reproducable as we'd have wanted them to be. Tooling can differ across machines because the operating systems are different, therefore yielding different versions of nodejs/iojs or different versions of sass bindings. The sass bindings are what pushed us over the edge to try out Dockers for sharing our build environment.

With the advent of user-namespaces in Docker, mounting volumes with the right privileges has become transparent. (see http://www.jrslv.com/docker-1-10/#usernamespacesindocker for some basic info)

The arguments you need to pass to the Docker run command for it to be useful are too cumbersome, hence we've created scripts to help you out.