Quilt.js

Documentation for quilt.js

Container

The Container object represents a container to be deployed.

Specifying the Image

The first argument of the Container constructor is the image that container should run.

Repository Link

If a string is supplied, the image at that repository is used.

Dockerfile

Instead of supplying a link to a pre-built image, Quilt also support building images in the cluster. When specifying a Dockerfile to be built, an Image object must be passed to the Container constructor.

For example,

new Container(new Image("my-image-name",
  "FROM nginx\n" +
  "RUN cd /web_root && git clone github.com/my/web_repo"
))

would deploy an image called my-image-name built on top of the nginx image, with the github.com/my/web_repo repository cloned into /web_root.

If the Dockerfile is saved as a file, it can simply be read in:

new Container(new Image("my-image-name", read("./Dockerfile")))

If a user runs a spec that uses a custom image, then runs another spec that changes the contents of that image's Dockerfile, the image is re-built and all containers referencing that Dockerfile are restarted with the new image.

If multiple containers specify the same Dockerfile, the same image is reused for all containers.

If two images with the same name but different Dockerfiles are referenced, an error is thrown.

Container.filepathToContent

Container.filepathToContent defines text files to be installed on the container before the container starts. Both the key and value are strings.

For example,

{
  "/etc/myconf": "foo"
}

would create a file at /etc/myconf containing the text foo.

new Container("haproxy").withFiles({
  "/etc/myconf": "foo"
});

would create a haproxy instance with a text file /etc/myconf containing foo.

If the files change after the container boots, Quilt does not restart the container. However, if the file content specified by filepathToContent changes, Quilt will destroy the old container and boot a new one with the proper files.

The files are installed with permissions 0644. Parent directories are automatically created.

Container.hostname()

Container.hostname gets the container's hostname. If the container has no hostname, an error is thrown.

Container.setHostname()

Container.setHostname gives the container a hostname at which the container can be reached.

If multiple containers have the same hostname, an error is thrown during the vetting process.

Machine

The Machine object represents a machine to be deployed.

Its attributes are:

• role string: The Quilt role the machine will run as. required
  • Master
  • Worker
• provider string: The machine provider. required
  • Amazon
  • DigitalOcean
  • Google
• region string: The region the machine will run in. optional
  • Provider-specific
• size string: The instance type. optional
  • Provider-specific
• cpu Range or int: The desired number of CPUs. optional
• ram Range or int: The desired amount of RAM in Gib. optional
• diskSize int: The desired amount of disk space in GB. optional
• floatingIp string: A reserved IP to associate with the machine. optional
• sshKeys []string: Public keys to allow login into the machine. optional
• preemptible bool: Whether the machine should be preemptible. optional
  • Defaults to false
  • Preemptible instances are only supported on the Amazon provider.

Files

Quilt.js has some basic support for reading files from the local filesystem which can be used either as Dockerfiles for container images, or imported directly into a container at boot. These utilities should be considered experimental and are likely subject to change.

read()

read() reads the contents of a file into a string. The file path is passed in as an argument to the function. For example, in the below example, contents will contain a string representing the contents of the file located at /path/to/file.txt.

var contents = read("/path/to/file.txt")

readDir()

readDir() lists the contents of a directory. It takes the file path of a directory as its only argument, and returns a list of objects representing files in that directory. Each object contains the fields name (the name of the file), and isDir (true if the path is a directory instead of a file). For example, in the walk() function below, readDir() is used to recursively execute a callback on every file in a directory.

function walk(path, fn) {
        var files = readDir(path);
        for (var i = 0; i < files.length; i++) {
                var filePath = path + "/" + files[i].name;
                if (files[i].isDir) {
                        walk(filePath, fn);
                } else {
                        fn(filePath)
                }
        }
}