Official Go implementation of the Ethereum protocol
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go-ethereum/p2p/simulations/adapters/docker.go

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// 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/log"
"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
conf.Stack.Logger = log.New("node.id", config.ID.String())
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
}