Using Dockerfiles

Drycc supports deploying applications using Dockerfiles. A Dockerfile automates the process of building a [Container Image][] that defines your application’s runtime environment. While Dockerfiles offer powerful customization, they require careful configuration to work with Drycc.

Add SSH Key

For Dockerfile-based deployments via git push, Drycc Workflow authenticates users using SSH keys. Each user must upload a unique SSH key to the platform.

• Generate an SSH key by following these instructions.
• Upload your SSH key using drycc keys add:

$ drycc keys add ~/.ssh/id_drycc.pub
Uploading id_drycc.pub to drycc... done

For more information about managing SSH keys, see this guide.

Prepare an Application

If you don’t have an existing application, clone this example application to explore the Dockerfile workflow:

$ git clone https://github.com/drycc/helloworld.git
$ cd helloworld

Dockerfile Requirements

Your Dockerfile must meet these requirements for successful deployment:

• Use the EXPOSE directive to expose exactly one port for HTTP traffic.
• Ensure your application listens for HTTP connections on that port.
• Define the default process using the CMD directive.
• Include bash in your container image.

Create an Application

Create an application on the Controller:

$ drycc create
Creating application... done, created folksy-offshoot
Git remote drycc added

Push to Deploy

Deploy your application using git push drycc master:

$ git push drycc master
Counting objects: 13, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (13/13), done.
Writing objects: 100% (13/13), 1.99 KiB | 0 bytes/s, done.
Total 13 (delta 2), reused 0 (delta 0)
-----> Building Docker image
Uploading context 4.096 kB
Uploading context
Step 0 : FROM drycc/base:latest
 ---> 60024338bc63
Step 1 : RUN wget -O /tmp/go1.2.1.linux-amd64.tar.gz -q https://go.googlecode.com/files/go1.2.1.linux-amd64.tar.gz
 ---> Using cache
 ---> cf9ef8c5caa7
Step 2 : RUN tar -C /usr/local -xzf /tmp/go1.2.1.linux-amd64.tar.gz
 ---> Using cache
 ---> 515b1faf3bd8
Step 3 : RUN mkdir -p /go
 ---> Using cache
 ---> ebf4927a00e9
Step 4 : ENV GOPATH /go
 ---> Using cache
 ---> c6a276eded37
Step 5 : ENV PATH /usr/local/go/bin:/go/bin:$PATH
 ---> Using cache
 ---> 2ba6f6c9f108
Step 6 : ADD . /go/src/github.com/drycc/helloworld
 ---> 94ab7f4b977b
Removing intermediate container 171b7d9fdb34
Step 7 : RUN cd /go/src/github.com/drycc/helloworld && go install -v .
 ---> Running in 0c8fbb2d2812
github.com/drycc/helloworld
 ---> 13b5af931393
Removing intermediate container 0c8fbb2d2812
Step 8 : ENV PORT 80
 ---> Running in 9b07da36a272
 ---> 2dce83167874
Removing intermediate container 9b07da36a272
Step 9 : CMD ["/go/bin/helloworld"]
 ---> Running in f7b215199940
 ---> b1e55ce5195a
Removing intermediate container f7b215199940
Step 10 : EXPOSE 80
 ---> Running in 7eb8ec45dcb0
 ---> ea1a8cc93ca3
Removing intermediate container 7eb8ec45dcb0
Successfully built ea1a8cc93ca3
-----> Pushing image to private registry

       Launching... done, v2

-----> folksy-offshoot deployed to Drycc
       http://folksy-offshoot.local3.dryccapp.com

       To learn more, use `drycc help` or visit https://www.drycc.cc

To ssh://git@local3.dryccapp.com:2222/folksy-offshoot.git
 * [new branch]      master -> master

$ curl -s http://folksy-offshoot.local3.dryccapp.com
Welcome to Drycc!
See the documentation at http://docs.drycc.cc/ for more information.

Drycc automatically detects Dockerfile applications and scales the web process type to 1 on first deployment.

Scale your application by adjusting the number of containers. For example, use drycc scale web=3 to run 3 web containers.

Container Build Arguments

Starting with Workflow v2.13.0, you can inject application configuration into your container image using Docker build arguments. Enable this feature by setting an environment variable:

$ drycc config set DRYCC_DOCKER_BUILD_ARGS_ENABLED=1

Once enabled, all environment variables set with drycc config set become available in your Dockerfile. For example, after running drycc config set POWERED_BY=Workflow, you can use this build argument in your Dockerfile:

ARG POWERED_BY
RUN echo "Powered by $POWERED_BY" > /etc/motd