Add docker.io Drone plugin which creates a docker image for each successful build

This change adds a new Drone plugin for creating a docker image. The plugin
creates a docker image for the test build and pushes the image to images.docker.io.

pkg/plugin/publish/docker.go

@@ -0,0 +1,65 @@
+package publish
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/drone/drone/pkg/build/buildfile"
+	"github.com/drone/drone/pkg/build/repo"
+)
+
+type Docker struct {
+	// The path to the dockerfile to create the image from
+	Dockerfile string `yaml:"docker_file"`
+
+	// Connection information for the docker server that will build the image
+	Server string `yaml:"docker_server"`
+	Port   int    `yaml:"docker_port"`
+	// The Docker client version to download. This must match the docker version on the server
+	DockerVersion string `yaml:"docker_version"`
+
+	RepoBaseName string `yaml:"repo_base_name"`
+
+	// Authentication credentials for index.docker.io
+	Username string `yaml:"username"`
+	Password string `yaml:"password"`
+	Email    string `yaml:"email"`
+
+	Branch string `yaml:"branch,omitempty"`
+}
+
+// Write adds commands to the buildfile to do the following:
+// 1. Install the docker client in the Drone container.
+// 2. Build a docker image based on the dockerfile defined in the config.
+// 3. Push that docker image to index.docker.io.
+// 4. Delete the docker image on the server it was build on so we conserve disk space.
+func (d *Docker) Write(f *buildfile.Buildfile, r *repo.Repo) {
+	if len(d.Dockerfile) == 0 || len(d.Server) == 0 || d.Port == 0 || len(d.DockerVersion) == 0 ||
+		len(d.RepoBaseName) == 0 || len(d.Username) == 0 || len(d.Password) == 0 ||
+		len(d.Email) == 0 {
+		f.WriteCmdSilent(`echo "Docker Plugin: Missing argument(s)"`)
+		return
+	}
+
+	// Install Docker on the container
+	f.WriteCmd("sudo sh -c \"echo deb http://get.docker.io/ubuntu docker main\\ > " +
+		"/etc/apt/sources.list.d/docker.list\"")
+	f.WriteCmd("sudo apt-get update")
+	f.WriteCmd("sudo apt-get --yes install lxc-docker-" + d.DockerVersion)
+
+	dockerServerUrl := d.Server + ":" + strconv.Itoa(d.Port)
+	dockerRepo := d.RepoBaseName + "/" + r.Name
+	// Run the command commands to build and deploy the image. Note that the image is tagged
+	// with the git hash.
+	f.WriteCmd(fmt.Sprintf("docker -H %s build -t %s:$(git rev-parse --short HEAD) - < %s",
+		dockerServerUrl, dockerRepo, d.Dockerfile))
+
+	// Login and push to index.docker.io
+	f.WriteCmd(fmt.Sprintf("docker -H %s login -u %s -p %s -e %s",
+		dockerServerUrl, d.Username, d.Password, d.Email))
+	f.WriteCmd(fmt.Sprintf("docker -H %s push %s", dockerServerUrl, dockerRepo))
+
+        // Delete the image from the docker server we built on.
+	f.WriteCmd(fmt.Sprintf("docker -H %s rmi %s:$(git rev-parse --short HEAD)",
+		dockerServerUrl, dockerRepo))
+}

pkg/plugin/publish/publish.go

@@ -9,10 +9,11 @@ import (
 // for publishing build artifacts when
 // a Build has succeeded
 type Publish struct {
-	S3    *S3    `yaml:"s3,omitempty"`
+	S3     *S3     `yaml:"s3,omitempty"`
-	Swift *Swift `yaml:"swift,omitempty"`
+	Swift  *Swift  `yaml:"swift,omitempty"`
-	PyPI  *PyPI  `yaml:"pypi,omitempty"`
+	PyPI   *PyPI   `yaml:"pypi,omitempty"`
-	NPM   *NPM   `yaml:"npm,omitempty"`
+	NPM    *NPM    `yaml:"npm,omitempty"`
+	Docker *Docker `yaml:"docker,omitempty"`
 }
 
 func (p *Publish) Write(f *buildfile.Buildfile, r *repo.Repo) {
@@ -35,4 +36,9 @@ func (p *Publish) Write(f *buildfile.Buildfile, r *repo.Repo) {
 	if p.NPM != nil && (len(p.NPM.Branch) == 0 || (len(p.NPM.Branch) > 0 && r.Branch == p.NPM.Branch)) {
 		p.NPM.Write(f)
 	}
+
+	// Docker
+	if p.Docker != nil && (len(p.Docker.Branch) == 0 || (len(p.Docker.Branch) > 0 && r.Branch == p.Docker.Branch)) {
+		p.Docker.Write(f, r)
+	}
 }