api,fn: entrypoint to return daemon version (#367)

fn/version.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+	"net/url"
+	"os"
+
+	functions "github.com/iron-io/functions_go"
+	"github.com/urfave/cli"
+)
+
+func version() cli.Command {
+	r := versionCmd{VersionApi: functions.NewVersionApi()}
+	return cli.Command{
+		Name:   "version",
+		Usage:  "displays fn and functions daemon versions",
+		Action: r.version,
+	}
+}
+
+type versionCmd struct {
+	*functions.VersionApi
+}
+
+func (r *versionCmd) version(c *cli.Context) error {
+	apiURL := os.Getenv("API_URL")
+	if apiURL == "" {
+		apiURL = "http://localhost:8080"
+	}
+
+	u, err := url.Parse(apiURL)
+	if err != nil {
+		return err
+	}
+	r.Configuration.BasePath = u.String()
+
+	fmt.Println("Client version:", fnversion)
+	v, _, err := r.VersionGet()
+	if err != nil {
+		return err
+	}
+	fmt.Println("Server version", v.Version)
+	return nil
+}