Add basic frame and ctr command line client

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

api/v1/client.go

@@ -0,0 +1,70 @@
+package v1
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+func NewClient(addr string) *Client {
+	return &Client{
+		addr: addr,
+	}
+}
+
+type Client struct {
+	addr string
+}
+
+// Start starts a container with the specified id and path to the container's
+// bundle on the system.
+func (c *Client) Start(id, path string) error {
+	container := Container{
+		BundlePath: path,
+	}
+	buf := bytes.NewBuffer(nil)
+	if err := json.NewEncoder(buf).Encode(container); err != nil {
+		return err
+	}
+	r, err := http.Post(c.addr+"/containers/"+id, "application/json", buf)
+	if err != nil {
+		return err
+	}
+	r.Body.Close()
+	if r.StatusCode != http.StatusCreated {
+		return fmt.Errorf("unexpected status %d", r.StatusCode)
+	}
+	return nil
+}
+
+// Containers returns all running containers within containerd.
+func (c *Client) Containers() ([]Container, error) {
+	r, err := http.Get(c.addr + "/containers")
+	if err != nil {
+		return nil, err
+	}
+	var s State
+	if err := json.NewDecoder(r.Body).Decode(&s); err != nil {
+		return nil, err
+	}
+	r.Body.Close()
+	return s.Containers, nil
+}
+
+func (c *Client) Signal(id string, pid, signal int) error {
+	sig := Signal{
+		Signal: signal,
+	}
+	buf := bytes.NewBuffer(nil)
+	if err := json.NewEncoder(buf).Encode(sig); err != nil {
+		return err
+	}
+	r, err := http.Post(c.addr+"/containers/"+id+"/process/"+strconv.Itoa(pid), "application/json", buf)
+	if err != nil {
+		return err
+	}
+	r.Body.Close()
+	return nil
+}