First-pass rewrite of docker code

docker.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"fmt"
+	"github.com/csmith/dotege/model"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/events"
+	"github.com/docker/docker/api/types/filters"
+	"golang.org/x/net/context"
+)
+
+type DockerClient interface {
+	Events(ctx context.Context, options types.EventsOptions) (<-chan events.Message, <-chan error)
+	ContainerList(ctx context.Context, options types.ContainerListOptions) ([]types.Container, error)
+	ContainerInspect(ctx context.Context, containerID string) (types.ContainerJSON, error)
+}
+
+func monitorContainers(client DockerClient, stop <-chan struct{}, addedFn func(model.Container), removedFn func(string)) error {
+	ctx, cancel := context.WithCancel(context.Background())
+	stream, errors := startEventStream(client, ctx)
+
+	if err := publishExistingContainers(client, ctx, addedFn); err != nil {
+		cancel()
+		return err
+	}
+
+	for {
+		select {
+		case event := <-stream:
+			if event.Action == "create" {
+				err, container := inspectContainer(client, ctx, event.Actor.ID)
+				if err != nil {
+					cancel()
+					return err
+				}
+				addedFn(container)
+			} else {
+				removedFn(event.Actor.Attributes["name"])
+			}
+
+		case err := <-errors:
+			cancel()
+			return err
+
+		case <-stop:
+			cancel()
+			return nil
+		}
+	}
+}
+
+func startEventStream(client DockerClient, ctx context.Context) (<-chan events.Message, <-chan error) {
+	args := filters.NewArgs()
+	args.Add("type", "container")
+	args.Add("event", "create")
+	args.Add("event", "destroy")
+	return client.Events(ctx, types.EventsOptions{Filters: args})
+}
+
+func publishExistingContainers(client DockerClient, ctx context.Context, addedFn func(model.Container)) error {
+	containers, err := client.ContainerList(ctx, types.ContainerListOptions{})
+	if err != nil {
+		return fmt.Errorf("unable to list containers: %s", err.Error())
+	}
+
+	for _, container := range containers {
+		addedFn(model.Container{
+			Id:     container.ID,
+			Name:   container.Names[0][1:],
+			Labels: container.Labels,
+		})
+	}
+	return nil
+}
+
+func inspectContainer(client DockerClient, ctx context.Context, id string) (error, model.Container) {
+	container, err := client.ContainerInspect(ctx, id)
+	if err != nil {
+		return err, model.Container{}
+	}
+
+	return nil, model.Container{
+		Id:     container.ID,
+		Name:   container.Name[1:],
+		Labels: container.Config.Labels,
+	}
+}