plugeth/p2p/simulations/adapters/docker.go
Lewis Marshall 9feec51e2d p2p: add network simulation framework (#14982)
This commit introduces a network simulation framework which
can be used to run simulated networks of devp2p nodes. The
intention is to use this for testing protocols, performing
benchmarks and visualising emergent network behaviour.
2017-09-25 10:08:07 +02:00

183 lines
5.1 KiB
Go

// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package adapters
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"runtime"
"strings"
"github.com/docker/docker/pkg/reexec"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p/discover"
)
// DockerAdapter is a NodeAdapter which runs simulation nodes inside Docker
// containers.
//
// A Docker image is built which contains the current binary at /bin/p2p-node
// which when executed runs the underlying service (see the description
// of the execP2PNode function for more details)
type DockerAdapter struct {
ExecAdapter
}
// NewDockerAdapter builds the p2p-node Docker image containing the current
// binary and returns a DockerAdapter
func NewDockerAdapter() (*DockerAdapter, error) {
// Since Docker containers run on Linux and this adapter runs the
// current binary in the container, it must be compiled for Linux.
//
// It is reasonable to require this because the caller can just
// compile the current binary in a Docker container.
if runtime.GOOS != "linux" {
return nil, errors.New("DockerAdapter can only be used on Linux as it uses the current binary (which must be a Linux binary)")
}
if err := buildDockerImage(); err != nil {
return nil, err
}
return &DockerAdapter{
ExecAdapter{
nodes: make(map[discover.NodeID]*ExecNode),
},
}, nil
}
// Name returns the name of the adapter for logging purposes
func (d *DockerAdapter) Name() string {
return "docker-adapter"
}
// NewNode returns a new DockerNode using the given config
func (d *DockerAdapter) NewNode(config *NodeConfig) (Node, error) {
if len(config.Services) == 0 {
return nil, errors.New("node must have at least one service")
}
for _, service := range config.Services {
if _, exists := serviceFuncs[service]; !exists {
return nil, fmt.Errorf("unknown node service %q", service)
}
}
// generate the config
conf := &execNodeConfig{
Stack: node.DefaultConfig,
Node: config,
}
conf.Stack.DataDir = "/data"
conf.Stack.WSHost = "0.0.0.0"
conf.Stack.WSOrigins = []string{"*"}
conf.Stack.WSExposeAll = true
conf.Stack.P2P.EnableMsgEvents = false
conf.Stack.P2P.NoDiscovery = true
conf.Stack.P2P.NAT = nil
conf.Stack.NoUSB = true
node := &DockerNode{
ExecNode: ExecNode{
ID: config.ID,
Config: conf,
adapter: &d.ExecAdapter,
},
}
node.newCmd = node.dockerCommand
d.ExecAdapter.nodes[node.ID] = &node.ExecNode
return node, nil
}
// DockerNode wraps an ExecNode but exec's the current binary in a docker
// container rather than locally
type DockerNode struct {
ExecNode
}
// dockerCommand returns a command which exec's the binary in a Docker
// container.
//
// It uses a shell so that we can pass the _P2P_NODE_CONFIG environment
// variable to the container using the --env flag.
func (n *DockerNode) dockerCommand() *exec.Cmd {
return exec.Command(
"sh", "-c",
fmt.Sprintf(
`exec docker run --interactive --env _P2P_NODE_CONFIG="${_P2P_NODE_CONFIG}" %s p2p-node %s %s`,
dockerImage, strings.Join(n.Config.Node.Services, ","), n.ID.String(),
),
)
}
// dockerImage is the name of the Docker image which gets built to run the
// simulation node
const dockerImage = "p2p-node"
// buildDockerImage builds the Docker image which is used to run the simulation
// node in a Docker container.
//
// It adds the current binary as "p2p-node" so that it runs execP2PNode
// when executed.
func buildDockerImage() error {
// create a directory to use as the build context
dir, err := ioutil.TempDir("", "p2p-docker")
if err != nil {
return err
}
defer os.RemoveAll(dir)
// copy the current binary into the build context
bin, err := os.Open(reexec.Self())
if err != nil {
return err
}
defer bin.Close()
dst, err := os.OpenFile(filepath.Join(dir, "self.bin"), os.O_WRONLY|os.O_CREATE, 0755)
if err != nil {
return err
}
defer dst.Close()
if _, err := io.Copy(dst, bin); err != nil {
return err
}
// create the Dockerfile
dockerfile := []byte(`
FROM ubuntu:16.04
RUN mkdir /data
ADD self.bin /bin/p2p-node
`)
if err := ioutil.WriteFile(filepath.Join(dir, "Dockerfile"), dockerfile, 0644); err != nil {
return err
}
// run 'docker build'
cmd := exec.Command("docker", "build", "-t", dockerImage, dir)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Run(); err != nil {
return fmt.Errorf("error building docker image: %s", err)
}
return nil
}