Initial merge of faas-containerd

This patch completes part of the work in #20 by porting the code
for faas-containerd in-tree. When tested, I was able to deploy
and then remove figlet from the store on `x86_64`.

In a follow-up PR, duplication will be removed where possible
and consolidated with updated documentation.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

pkg/provider/handlers/deploy.go

@@ -0,0 +1,179 @@
+package handlers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/alexellis/faasd/pkg/service"
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/cio"
+	"github.com/containerd/containerd/namespaces"
+	"github.com/containerd/containerd/oci"
+	gocni "github.com/containerd/go-cni"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/openfaas/faas-provider/types"
+	"github.com/pkg/errors"
+)
+
+func MakeDeployHandler(client *containerd.Client, cni gocni.CNI) func(w http.ResponseWriter, r *http.Request) {
+
+	return func(w http.ResponseWriter, r *http.Request) {
+
+		if r.Body == nil {
+			http.Error(w, "expected a body", http.StatusBadRequest)
+			return
+		}
+
+		defer r.Body.Close()
+
+		body, _ := ioutil.ReadAll(r.Body)
+		log.Printf("[Deploy] request: %s\n", string(body))
+
+		req := types.FunctionDeployment{}
+		err := json.Unmarshal(body, &req)
+		if err != nil {
+			log.Printf("[Deploy] - error parsing input: %s\n", err)
+			http.Error(w, err.Error(), http.StatusBadRequest)
+
+			return
+		}
+
+		name := req.Service
+
+		ctx := namespaces.WithNamespace(context.Background(), FunctionNamespace)
+
+		deployErr := deploy(ctx, req, client, cni)
+		if deployErr != nil {
+			log.Printf("[Deploy] error deploying %s, error: %s\n", name, deployErr)
+			http.Error(w, deployErr.Error(), http.StatusBadRequest)
+			return
+		}
+	}
+}
+
+func deploy(ctx context.Context, req types.FunctionDeployment, client *containerd.Client, cni gocni.CNI) error {
+
+	imgRef := "docker.io/" + req.Image
+	if strings.Index(req.Image, ":") == -1 {
+		imgRef = imgRef + ":latest"
+	}
+
+	snapshotter := ""
+	if val, ok := os.LookupEnv("snapshotter"); ok {
+		snapshotter = val
+	}
+
+	image, err := service.PrepareImage(ctx, client, imgRef, snapshotter)
+	if err != nil {
+		return errors.Wrapf(err, "unable to pull image %s", imgRef)
+	}
+
+	size, _ := image.Size(ctx)
+	log.Printf("Deploy %s size: %d\n", image.Name(), size)
+
+	envs := prepareEnv(req.EnvProcess, req.EnvVars)
+	mounts := getMounts()
+
+	name := req.Service
+
+	container, err := client.NewContainer(
+		ctx,
+		name,
+		containerd.WithImage(image),
+		containerd.WithSnapshotter(snapshotter),
+		containerd.WithNewSnapshot(req.Service+"-snapshot", image),
+		containerd.WithNewSpec(oci.WithImageConfig(image),
+			oci.WithCapabilities([]string{"CAP_NET_RAW"}),
+			oci.WithMounts(mounts),
+			oci.WithEnv(envs)),
+	)
+
+	if err != nil {
+		return fmt.Errorf("unable to create container: %s, error: %s", name, err)
+	}
+
+	return createTask(ctx, client, container, cni)
+
+}
+
+func createTask(ctx context.Context, client *containerd.Client, container containerd.Container, cni gocni.CNI) error {
+
+	name := container.ID()
+	task, taskErr := container.NewTask(ctx, cio.NewCreator(cio.WithStdio))
+	if taskErr != nil {
+		return fmt.Errorf("unable to start task: %s, error: %s", name, taskErr)
+	}
+
+	log.Printf("Container ID: %s\tTask ID %s:\tTask PID: %d\t\n", name, task.ID(), task.Pid())
+
+	labels := map[string]string{}
+	network, err := CreateCNINetwork(ctx, cni, task, labels)
+
+	if err != nil {
+		return err
+	}
+
+	ip, err := GetIPAddress(network, task)
+	if err != nil {
+		return err
+	}
+	log.Printf("%s has IP: %s.\n", name, ip.String())
+
+	_, waitErr := task.Wait(ctx)
+	if waitErr != nil {
+		return errors.Wrapf(waitErr, "Unable to wait for task to start: %s", name)
+	}
+
+	if startErr := task.Start(ctx); startErr != nil {
+		return errors.Wrapf(startErr, "Unable to start task: %s", name)
+	}
+	return nil
+}
+
+func prepareEnv(envProcess string, reqEnvVars map[string]string) []string {
+	envs := []string{}
+	fprocessFound := false
+	fprocess := "fprocess=" + envProcess
+	if len(envProcess) > 0 {
+		fprocessFound = true
+	}
+
+	for k, v := range reqEnvVars {
+		if k == "fprocess" {
+			fprocessFound = true
+			fprocess = v
+		} else {
+			envs = append(envs, k+"="+v)
+		}
+	}
+	if fprocessFound {
+		envs = append(envs, fprocess)
+	}
+	return envs
+}
+
+func getMounts() []specs.Mount {
+	wd, _ := os.Getwd()
+	mounts := []specs.Mount{}
+	mounts = append(mounts, specs.Mount{
+		Destination: "/etc/resolv.conf",
+		Type:        "bind",
+		Source:      path.Join(wd, "resolv.conf"),
+		Options:     []string{"rbind", "ro"},
+	})
+
+	mounts = append(mounts, specs.Mount{
+		Destination: "/etc/hosts",
+		Type:        "bind",
+		Source:      path.Join(wd, "hosts"),
+		Options:     []string{"rbind", "ro"},
+	})
+	return mounts
+}