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docker.go
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docker.go
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// Copyright 2020 Nokia
// Licensed under the BSD 3-Clause License.
// SPDX-License-Identifier: BSD-3-Clause
package docker
import (
"bytes"
"context"
"fmt"
"io"
"io/ioutil"
"path"
"strconv"
"strings"
"time"
dockerTypes "github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/api/types/filters"
"github.com/docker/docker/api/types/network"
dockerC "github.com/docker/docker/client"
"github.com/docker/docker/pkg/stdcopy"
"github.com/google/shlex"
log "github.com/sirupsen/logrus"
"github.com/srl-labs/containerlab/runtime"
"github.com/srl-labs/containerlab/types"
"github.com/srl-labs/containerlab/utils"
)
const (
runtimeName = "docker"
sysctlBase = "/proc/sys"
defaultTimeout = 30 * time.Second
)
func init() {
runtime.Register(runtimeName, func() runtime.ContainerRuntime {
return &DockerRuntime{
Mgmt: new(types.MgmtNet),
}
})
}
type DockerRuntime struct {
config runtime.RuntimeConfig
Client *dockerC.Client
Mgmt *types.MgmtNet
}
func (c *DockerRuntime) Init(opts ...runtime.RuntimeOption) error {
var err error
log.Debug("Runtime: Docker")
c.Client, err = dockerC.NewClientWithOpts(dockerC.FromEnv, dockerC.WithAPIVersionNegotiation())
if err != nil {
return err
}
for _, o := range opts {
o(c)
}
return nil
}
func (c *DockerRuntime) WithKeepMgmtNet() {
c.config.KeepMgmtNet = true
}
func (c *DockerRuntime) GetName() string { return runtimeName }
func (c *DockerRuntime) Config() runtime.RuntimeConfig { return c.config }
func (c *DockerRuntime) WithConfig(cfg *runtime.RuntimeConfig) {
c.config.Timeout = cfg.Timeout
c.config.Debug = cfg.Debug
c.config.GracefulShutdown = cfg.GracefulShutdown
if c.config.Timeout <= 0 {
c.config.Timeout = defaultTimeout
}
}
func (c *DockerRuntime) WithMgmtNet(n *types.MgmtNet) {
c.Mgmt = n
}
// CreateDockerNet creates a docker network or reusing if it exists
func (c *DockerRuntime) CreateNet(ctx context.Context) (err error) {
nctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
// linux bridge name that is used by docker network
bridgeName := c.Mgmt.Bridge
log.Debugf("Checking if docker network '%s' exists", c.Mgmt.Network)
netResource, err := c.Client.NetworkInspect(nctx, c.Mgmt.Network, dockerTypes.NetworkInspectOptions{})
switch {
case dockerC.IsErrNotFound(err):
log.Debugf("Network '%s' does not exist", c.Mgmt.Network)
log.Infof("Creating docker network: Name='%s', IPv4Subnet='%s', IPv6Subnet='%s', MTU='%s'",
c.Mgmt.Network, c.Mgmt.IPv4Subnet, c.Mgmt.IPv6Subnet, c.Mgmt.MTU)
enableIPv6 := false
var ipamConfig []network.IPAMConfig
if c.Mgmt.IPv4Subnet != "" {
ipamConfig = append(ipamConfig, network.IPAMConfig{
Subnet: c.Mgmt.IPv4Subnet,
})
}
if c.Mgmt.IPv6Subnet != "" {
ipamConfig = append(ipamConfig, network.IPAMConfig{
Subnet: c.Mgmt.IPv6Subnet,
})
enableIPv6 = true
}
ipam := &network.IPAM{
Driver: "default",
Config: ipamConfig,
}
netwOpts := map[string]string{
"com.docker.network.driver.mtu": c.Mgmt.MTU,
}
if bridgeName != "" {
netwOpts["com.docker.network.bridge.name"] = bridgeName
}
opts := dockerTypes.NetworkCreate{
CheckDuplicate: true,
Driver: "bridge",
EnableIPv6: enableIPv6,
IPAM: ipam,
Internal: false,
Attachable: false,
Labels: map[string]string{
"containerlab": "",
},
Options: netwOpts,
}
netCreateResponse, err := c.Client.NetworkCreate(nctx, c.Mgmt.Network, opts)
if err != nil {
return err
}
if len(netCreateResponse.ID) < 12 {
return fmt.Errorf("could not get bridge ID")
}
// when bridge is not set by a user explicitly
// we use the 12 chars of docker net as its name
if bridgeName == "" {
bridgeName = "br-" + netCreateResponse.ID[:12]
}
case err == nil:
log.Debugf("network '%s' was found. Reusing it...", c.Mgmt.Network)
if len(netResource.ID) < 12 {
return fmt.Errorf("could not get bridge ID")
}
switch c.Mgmt.Network {
case "bridge":
bridgeName = "docker0"
default:
if netResource.Options["com.docker.network.bridge.name"] != "" {
bridgeName = netResource.Options["com.docker.network.bridge.name"]
} else {
bridgeName = "br-" + netResource.ID[:12]
}
}
default:
return err
}
if c.Mgmt.Bridge == "" {
c.Mgmt.Bridge = bridgeName
}
log.Debugf("Docker network '%s', bridge name '%s'", c.Mgmt.Network, bridgeName)
log.Debug("Disable RPF check on the docker host")
err = setSysctl("net/ipv4/conf/all/rp_filter", 0)
if err != nil {
return fmt.Errorf("failed to disable RP filter on docker host for the 'all' scope: %v", err)
}
err = setSysctl("net/ipv4/conf/default/rp_filter", 0)
if err != nil {
return fmt.Errorf("failed to disable RP filter on docker host for the 'default' scope: %v", err)
}
log.Debugf("Enable LLDP on the linux bridge %s", bridgeName)
file := "/sys/class/net/" + bridgeName + "/bridge/group_fwd_mask"
err = ioutil.WriteFile(file, []byte(strconv.Itoa(16384)), 0640)
if err != nil {
log.Warnf("failed to enable LLDP on docker bridge: %v", err)
}
log.Debugf("Disabling TX checksum offloading for the %s bridge interface...", bridgeName)
err = utils.EthtoolTXOff(bridgeName)
if err != nil {
log.Warnf("failed to disable TX checksum offloading for the %s bridge interface: %v", bridgeName, err)
}
return nil
}
// DeleteNet deletes a docker bridge
func (c *DockerRuntime) DeleteNet(ctx context.Context) (err error) {
network := c.Mgmt.Network
if network == "bridge" || c.config.KeepMgmtNet {
log.Debugf("Skipping deletion of '%s' network", network)
return nil
}
nctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
nres, err := c.Client.NetworkInspect(ctx, network, dockerTypes.NetworkInspectOptions{})
if err != nil {
return err
}
numEndpoints := len(nres.Containers)
if numEndpoints > 0 {
if c.config.Debug {
log.Debugf("network '%s' has %d active endpoints, deletion skipped", c.Mgmt.Network, numEndpoints)
for _, endp := range nres.Containers {
log.Debugf("'%s' is connected to %s", endp.Name, network)
}
}
return nil
}
err = c.Client.NetworkRemove(nctx, network)
if err != nil {
return err
}
return nil
}
// CreateContainer creates a docker container
func (c *DockerRuntime) CreateContainer(ctx context.Context, node *types.NodeConfig) (interface{}, error) {
log.Infof("Creating container: %s", node.ShortName)
nctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
cmd, err := shlex.Split(node.Cmd)
if err != nil {
return nil, err
}
containerConfig := &container.Config{
Image: node.Image,
Cmd: cmd,
Env: utils.ConvertEnvs(node.Env),
AttachStdout: true,
AttachStderr: true,
Hostname: node.ShortName,
Tty: true,
User: node.User,
Labels: node.Labels,
ExposedPorts: node.PortSet,
MacAddress: node.MacAddress,
}
containerHostConfig := &container.HostConfig{
Binds: node.Binds,
PortBindings: node.PortBindings,
Sysctls: node.Sysctls,
Privileged: true,
NetworkMode: container.NetworkMode(c.Mgmt.Network),
}
containerNetworkingConfig := &network.NetworkingConfig{}
switch node.NetworkMode {
case "host":
containerHostConfig.NetworkMode = container.NetworkMode("host")
default:
containerHostConfig.NetworkMode = container.NetworkMode(c.Mgmt.Network)
containerNetworkingConfig.EndpointsConfig = map[string]*network.EndpointSettings{
c.Mgmt.Network: {
IPAMConfig: &network.EndpointIPAMConfig{
IPv4Address: node.MgmtIPv4Address,
IPv6Address: node.MgmtIPv6Address,
},
},
}
}
cont, err := c.Client.ContainerCreate(
nctx,
containerConfig,
containerHostConfig,
containerNetworkingConfig,
nil,
node.LongName,
)
if err != nil {
return nil, err
}
log.Debugf("Container '%s' create response: %v", node.ShortName, cont)
log.Debugf("Start container: %s", node.LongName)
err = c.StartContainer(ctx, cont.ID)
if err != nil {
return nil, err
}
log.Debugf("Container started: %s", node.LongName)
node.NSPath, err = c.GetNSPath(ctx, cont.ID)
if err != nil {
return nil, err
}
return nil, utils.LinkContainerNS(node.NSPath, node.LongName)
}
// GetNSPath inspects a container by its name/id and returns an netns path using the pid of a container
func (c *DockerRuntime) GetNSPath(ctx context.Context, containerId string) (string, error) {
nctx, cancelFn := context.WithTimeout(ctx, c.config.Timeout)
defer cancelFn()
cJSON, err := c.Client.ContainerInspect(nctx, containerId)
if err != nil {
return "", err
}
return "/proc/" + strconv.Itoa(cJSON.State.Pid) + "/ns/net", nil
}
func (c *DockerRuntime) PullImageIfRequired(ctx context.Context, imageName string) error {
filter := filters.NewArgs()
filter.Add("reference", imageName)
ilo := dockerTypes.ImageListOptions{
All: false,
Filters: filter,
}
log.Debugf("Looking up %s Docker image", imageName)
images, err := c.Client.ImageList(ctx, ilo)
if err != nil {
return err
}
// If Image doesn't exist, we need to pull it
if len(images) > 0 {
log.Debugf("Image %s present, skip pulling", imageName)
return nil
}
canonicalImageName := utils.GetCanonicalImageName(imageName)
log.Infof("Pulling %s Docker image", canonicalImageName)
reader, err := c.Client.ImagePull(ctx, canonicalImageName, dockerTypes.ImagePullOptions{})
if err != nil {
return err
}
defer reader.Close()
// must read from reader, otherwise image is not properly pulled
_, _ = io.Copy(ioutil.Discard, reader)
log.Infof("Done pulling %s", canonicalImageName)
return nil
}
// StartContainer starts a docker container
func (c *DockerRuntime) StartContainer(ctx context.Context, id string) error {
nctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
return c.Client.ContainerStart(nctx,
id,
dockerTypes.ContainerStartOptions{
CheckpointID: "",
CheckpointDir: "",
},
)
}
// ListContainers lists all containers with labels []string
func (c *DockerRuntime) ListContainers(ctx context.Context, gfilters []*types.GenericFilter) ([]types.GenericContainer, error) {
ctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
filter := c.buildFilterString(gfilters)
ctrs, err := c.Client.ContainerList(ctx, dockerTypes.ContainerListOptions{
All: true,
Filters: filter,
})
if err != nil {
return nil, err
}
var nr []dockerTypes.NetworkResource
if c.Mgmt.Network == "" {
nctx, cancel := context.WithTimeout(ctx, c.config.Timeout)
defer cancel()
// fetch containerlab created networks
f := filters.NewArgs()
f.Add("label", "containerlab")
nr, err = c.Client.NetworkList(nctx, dockerTypes.NetworkListOptions{
Filters: f,
})
if err != nil {
return nil, err
}
// fetch default bridge network
f = filters.NewArgs()
f.Add("name", "bridge")
bridgenet, err := c.Client.NetworkList(nctx, dockerTypes.NetworkListOptions{
Filters: f,
})
if err != nil {
return nil, err
}
nr = append(nr, bridgenet...)
}
return c.produceGenericContainerList(ctrs, nr)
}
func (c *DockerRuntime) GetContainer(ctx context.Context, containerID string) (*types.GenericContainer, error) {
var ctr *types.GenericContainer
gFilter := types.GenericFilter{
FilterType: "name",
Field: "",
Operator: "",
Match: containerID,
}
ctrs, err := c.ListContainers(ctx, []*types.GenericFilter{&gFilter})
if err != nil {
return ctr, err
}
if len(ctrs) != 1 {
return ctr, fmt.Errorf("found unexpected number of containers: %d", len(ctrs))
}
return &ctrs[0], nil
}
func (c *DockerRuntime) buildFilterString(gfilters []*types.GenericFilter) filters.Args {
filter := filters.NewArgs()
for _, filterentry := range gfilters {
filterstring := filterentry.Field
if filterentry.Operator != "exists" {
filterstring = filterstring + filterentry.Operator + filterentry.Match
}
log.Debug("Filterstring: " + filterstring)
filter.Add(filterentry.FilterType, filterstring)
}
return filter
}
// Transform docker-specific to generic container format
func (c *DockerRuntime) produceGenericContainerList(inputContainers []dockerTypes.Container, inputNetworkRessources []dockerTypes.NetworkResource) ([]types.GenericContainer, error) {
var result []types.GenericContainer
for _, i := range inputContainers {
ctr := types.GenericContainer{
Names: i.Names,
ID: i.ID,
ShortID: i.ID[:12],
Image: i.Image,
State: i.State,
Status: i.Status,
Labels: i.Labels,
NetworkSettings: &types.GenericMgmtIPs{
Set: false,
},
}
bridgeName := c.Mgmt.Network
// if bridgeName is "", try to find a network created by clab that the container is connected to
if bridgeName == "" && inputNetworkRessources != nil {
for _, nr := range inputNetworkRessources {
if _, ok := i.NetworkSettings.Networks[nr.Name]; ok {
bridgeName = nr.Name
break
}
}
}
if ifcfg, ok := i.NetworkSettings.Networks[bridgeName]; ok {
ctr.NetworkSettings.IPv4addr = ifcfg.IPAddress
ctr.NetworkSettings.IPv4pLen = ifcfg.IPPrefixLen
ctr.NetworkSettings.IPv6addr = ifcfg.GlobalIPv6Address
ctr.NetworkSettings.IPv6pLen = ifcfg.GlobalIPv6PrefixLen
ctr.NetworkSettings.Set = true
}
result = append(result, ctr)
}
return result, nil
}
// Exec executes cmd on container identified with id and returns stdout, stderr bytes and an error
func (c *DockerRuntime) Exec(ctx context.Context, id string, cmd []string) ([]byte, []byte, error) {
cont, err := c.Client.ContainerInspect(ctx, id)
if err != nil {
return nil, nil, err
}
execID, err := c.Client.ContainerExecCreate(ctx, id, dockerTypes.ExecConfig{
User: "root",
AttachStderr: true,
AttachStdout: true,
Cmd: cmd,
})
if err != nil {
log.Errorf("failed to create exec in container %s: %v", cont.Name, err)
return nil, nil, err
}
log.Debugf("%s exec created %v", cont.Name, id)
rsp, err := c.Client.ContainerExecAttach(ctx, execID.ID, dockerTypes.ExecStartCheck{})
if err != nil {
log.Errorf("failed exec in container %s: %v", cont.Name, err)
return nil, nil, err
}
defer rsp.Close()
log.Debugf("%s exec attached %v", cont.Name, id)
var outBuf, errBuf bytes.Buffer
outputDone := make(chan error)
go func() {
_, err = stdcopy.StdCopy(&outBuf, &errBuf, rsp.Reader)
outputDone <- err
}()
select {
case err := <-outputDone:
if err != nil {
return outBuf.Bytes(), errBuf.Bytes(), err
}
case <-ctx.Done():
return nil, nil, ctx.Err()
}
return outBuf.Bytes(), errBuf.Bytes(), nil
}
// ExecNotWait executes cmd on container identified with id but doesn't wait for output nor attaches stodout/err
func (c *DockerRuntime) ExecNotWait(ctx context.Context, id string, cmd []string) error {
execConfig := dockerTypes.ExecConfig{Tty: false, AttachStdout: false, AttachStderr: false, Cmd: cmd}
respID, err := c.Client.ContainerExecCreate(context.Background(), id, execConfig)
if err != nil {
return err
}
execStartCheck := dockerTypes.ExecStartCheck{}
_, err = c.Client.ContainerExecAttach(context.Background(), respID.ID, execStartCheck)
if err != nil {
return err
}
return nil
}
// DeleteContainer tries to stop a container then remove it
func (c *DockerRuntime) DeleteContainer(ctx context.Context, containerID string) error {
var err error
force := !c.config.GracefulShutdown
if c.config.GracefulShutdown {
log.Infof("Stopping container: %s", containerID)
err = c.Client.ContainerStop(ctx, containerID, &c.config.Timeout)
if err != nil {
log.Errorf("could not stop container '%s': %v", containerID, err)
force = true
}
}
log.Debugf("Removing container: %s", strings.TrimLeft(containerID, "/"))
err = c.Client.ContainerRemove(ctx, containerID, dockerTypes.ContainerRemoveOptions{Force: force})
if err != nil {
return err
}
log.Infof("Removed container: %s", strings.TrimLeft(containerID, "/"))
return nil
}
// setSysctl writes sysctl data by writing to a specific file
func setSysctl(sysctl string, newVal int) error {
return ioutil.WriteFile(path.Join(sysctlBase, sysctl), []byte(strconv.Itoa(newVal)), 0640)
}
func (c *DockerRuntime) StopContainer(ctx context.Context, name string) error {
return c.Client.ContainerKill(ctx, name, "kill")
}