dockerutil

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 Go to latest Published: Dec 29, 2021 License: Apache-2.0, MIT Imports: 27 Imported by: 0

README

dockerutil

This package is for creating and controlling docker containers for testing runsc, gVisor's docker/kubernetes binary. A simple test may look like:

 func TestSuperCool(t *testing.T) {
   ctx := context.Background()
   c := dockerutil.MakeContainer(ctx, t)
   got, err := c.Run(ctx, dockerutil.RunOpts{
     Image: "basic/alpine"
   }, "echo", "super cool")
   if err != nil {
      t.Fatalf("err was not nil: %v", err)
   }
   want := "super cool"
   if !strings.Contains(got, want){
     t.Fatalf("want: %s, got: %s", want, got)
   }
 }

For further examples, see many of our end to end tests elsewhere in the repo, such as those in //test/e2e or benchmarks at //test/benchmarks.

dockerutil uses the "official" docker golang api, which is very powerful. dockerutil is a thin wrapper around this API, allowing desired new use cases to be easily implemented.

Profiling

dockerutil is capable of generating profiles. Currently, the only option is to use pprof profiles generated by runsc debug. The profiler will generate Block, CPU, Heap, Goroutine, and Mutex profiles. To generate profiles:

  • Install runsc with the --profile flag: make configure RUNTIME=myrunsc ARGS="--profile" Also add other flags with ARGS like --platform=kvm or --vfs2.
  • Restart docker: sudo service docker restart

To run and generate CPU profiles run:

make sudo TARGETS=//path/to:target \
  ARGS="--runtime=myrunsc -test.v -test.bench=. --pprof-cpu" OPTIONS="-c opt"

Profiles would be at: /tmp/profile/myrunsc/CONTAINERNAME/cpu.pprof

Container name in most tests and benchmarks in gVisor is usually the test name and some random characters like so: BenchmarkABSL-CleanCache-JF2J2ZYF3U7SL47QAA727CSJI3C4ZAW2

Profiling requires root as runsc debug inspects running containers in /var/run among other things.

Writing for Profiling

The below shows an example of using profiles with dockerutil.

func TestSuperCool(t *testing.T){
  ctx := context.Background()
  // profiled and using runtime from dockerutil.runtime flag
  profiled := MakeContainer()

  // not profiled and using runtime runc
  native := MakeNativeContainer()

  err := profiled.Spawn(ctx, RunOpts{
    Image: "some/image",
  }, "sleep", "100000")
  // profiling has begun here
  ...
  expensive setup that I don't want to profile.
  ...
  profiled.RestartProfiles()
  // profiled activity
}

In the above example, profiled would be profiled and native would not. The call to RestartProfiles() restarts the clock on profiling. This is useful if the main activity being tested is done with docker exec or container.Spawn() followed by one or more container.Exec() calls.

Documentation

Overview

Package dockerutil is a collection of utility functions.

Index

Constants

This section is empty.

Variables

View Source 
var ErrNoIP = errors.New("no IP available")

ErrNoIP indicates that no IP address is available.

Functions

func EnsureSupportedDockerVersion 

func EnsureSupportedDockerVersion()

EnsureSupportedDockerVersion checks if correct docker is installed.

This logs directly to stderr, as it is typically called from a Main wrapper.

func Runtime 

func Runtime() string

Runtime returns the value of the flag runtime.

func RuntimePath 

func RuntimePath() (string, error)

RuntimePath returns the binary path for the current runtime.

func Save 

func Save(logger testutil.Logger, image string, w io.Writer) error

Save exports a container image to the given Writer.

Note that the writer should be actively consuming the output, otherwise it is not guaranteed that the Save will make any progress and the call may stall indefinitely.

This is called by criutil in order to import imports.

func UsingVFS2 

func UsingVFS2() (bool, error)

UsingVFS2 returns true if the 'runtime' has the vfs2 flag set. TODO(gvisor.dev/issue/1624): Remove.

Types

type Container 

type Container struct {
	Name string
	// contains filtered or unexported fields
}

Container represents a Docker Container allowing user to configure and control as one would with the 'docker' client. Container is backed by the offical golang docker API. See: https://pkg.go.dev/github.com/docker/docker.

func MakeContainer 

func MakeContainer(ctx context.Context, logger testutil.Logger) *Container

MakeContainer constructs a suitable Container object.

The runtime used is determined by the runtime flag.

Containers will check flags for profiling requests.

func MakeNativeContainer 

func MakeNativeContainer(ctx context.Context, logger testutil.Logger) *Container

MakeNativeContainer constructs a suitable Container object.

The runtime used will be the system default.

Native containers aren't profiled.

func (*Container) Checkpoint 

func (c *Container) Checkpoint(ctx context.Context, name string) error

Checkpoint is analogous to 'docker checkpoint'.

func (*Container) CleanUp 

func (c *Container) CleanUp(ctx context.Context)

CleanUp kills and deletes the container (best effort).

func (*Container) ConfigsFrom 

func (c *Container) ConfigsFrom(r RunOpts, args ...string) (*container.Config, *container.HostConfig, *network.NetworkingConfig)

ConfigsFrom returns container configs from RunOpts and args. The caller should call 'CreateFrom' and Start.

func (*Container) CopyFiles 

func (c *Container) CopyFiles(opts *RunOpts, target string, sources ...string)

CopyFiles copies in and mounts the given files. They are always ReadOnly.

func (*Container) Create 

func (c *Container) Create(ctx context.Context, r RunOpts, args ...string) error

Create is analogous to 'docker create'.

func (*Container) CreateFrom 

func (c *Container) CreateFrom(ctx context.Context, profileImage string, conf *container.Config, hostconf *container.HostConfig, netconf *network.NetworkingConfig) error

CreateFrom creates a container from the given configs.

func (*Container) Exec 

func (c *Container) Exec(ctx context.Context, opts ExecOpts, args ...string) (string, error)

Exec creates a process inside the container.

func (*Container) ExecProcess 

func (c *Container) ExecProcess(ctx context.Context, opts ExecOpts, args ...string) (Process, error)

ExecProcess creates a process inside the container and returns a process struct for the caller to use.

func (*Container) FindIP 

func (c *Container) FindIP(ctx context.Context, ipv6 bool) (net.IP, error)

FindIP returns the IP address of the container.

func (*Container) FindPort 

func (c *Container) FindPort(ctx context.Context, sandboxPort int) (int, error)

FindPort returns the host port that is mapped to 'sandboxPort'.

func (*Container) ID 

func (c *Container) ID() string

ID returns the container id.

func (*Container) Kill 

func (c *Container) Kill(ctx context.Context) error

Kill kills the container.

func (*Container) Logs 

func (c *Container) Logs(ctx context.Context) (string, error)

Logs is analogous 'docker logs'. 

func (c *Container) MakeLink(target string) string

MakeLink formats a link to add to a RunOpts.

func (*Container) Pause 

func (c *Container) Pause(ctx context.Context) error

Pause is analogous to'docker pause'.

func (*Container) Remove 

func (c *Container) Remove(ctx context.Context) error

Remove is analogous to 'docker rm'.

func (*Container) Restore 

func (c *Container) Restore(ctx context.Context, name string) error

Restore is analogous to 'docker start --checkname [name]'.

func (*Container) Run 

func (c *Container) Run(ctx context.Context, r RunOpts, args ...string) (string, error)

Run is analogous to 'docker run'.

func (*Container) SandboxPid 

func (c *Container) SandboxPid(ctx context.Context) (int, error)

SandboxPid returns the container's pid.

func (*Container) Spawn 

func (c *Container) Spawn(ctx context.Context, r RunOpts, args ...string) error

Spawn is analogous to 'docker run -d'.

func (*Container) SpawnProcess 

func (c *Container) SpawnProcess(ctx context.Context, r RunOpts, args ...string) (Process, error)

SpawnProcess is analogous to 'docker run -it'. It returns a process which represents the root process.

func (*Container) Start 

func (c *Container) Start(ctx context.Context) error

Start is analogous to 'docker start'.

func (*Container) Status 

func (c *Container) Status(ctx context.Context) (types.ContainerState, error)

Status inspects the container returns its status.

func (*Container) Stop 

func (c *Container) Stop(ctx context.Context) error

Stop is analogous to 'docker stop'.

func (*Container) Unpause 

func (c *Container) Unpause(ctx context.Context) error

Unpause is analogous to 'docker unpause'.

func (*Container) Wait 

func (c *Container) Wait(ctx context.Context) error

Wait waits for the container to exit.

func (*Container) WaitForOutput 

func (c *Container) WaitForOutput(ctx context.Context, pattern string, timeout time.Duration) (string, error)

WaitForOutput searches container logs for pattern and returns or timesout.

func (*Container) WaitForOutputSubmatch 

func (c *Container) WaitForOutputSubmatch(ctx context.Context, pattern string, timeout time.Duration) ([]string, error)

WaitForOutputSubmatch searches container logs for the given pattern or times out. It returns any regexp submatches as well.

func (*Container) WaitTimeout 

func (c *Container) WaitTimeout(ctx context.Context, timeout time.Duration) error

WaitTimeout waits for the container to exit with a timeout.

type ExecOpts 

type ExecOpts struct {
	// Env are additional environment variables.
	Env []string

	// Privileged enables privileged mode.
	Privileged bool

	// User is the user to use.
	User string

	// Enables Tty and stdin for the created process.
	UseTTY bool

	// WorkDir is the working directory of the process.
	WorkDir string
}

ExecOpts holds arguments for Exec calls.

type Network 

type Network struct {
	Name string

	Subnet *net.IPNet
	// contains filtered or unexported fields
}

Network is a docker network.

func NewNetwork 

func NewNetwork(ctx context.Context, logger testutil.Logger) *Network

NewNetwork sets up the struct for a Docker network. Names of networks will be unique.

func (*Network) Cleanup 

func (n *Network) Cleanup(ctx context.Context) error

Cleanup cleans up the docker network.

func (*Network) Connect 

func (n *Network) Connect(ctx context.Context, container *Container, ipv4, ipv6 string) error

Connect is analogous to 'docker network connect' with the arguments provided.

func (*Network) Create 

func (n *Network) Create(ctx context.Context) error

Create is analogous to 'docker network create'.

func (*Network) Inspect 

func (n *Network) Inspect(ctx context.Context) (types.NetworkResource, error)

Inspect returns this network's info.

type Process 

type Process struct {
	// contains filtered or unexported fields
}

Process represents a containerized process.

func (*Process) ExitCode 

func (p *Process) ExitCode(ctx context.Context) (int, error)

ExitCode returns the process's exit code.

func (*Process) IsRunning 

func (p *Process) IsRunning(ctx context.Context) (bool, error)

IsRunning checks if the process is running.

func (*Process) Logs 

func (p *Process) Logs() (string, error)

Logs returns combined stdout/stderr from the process.

func (*Process) Read 

func (p *Process) Read() (string, string, error)

Read returns process's stdout and stderr.

func (*Process) WaitExitStatus 

func (p *Process) WaitExitStatus(ctx context.Context) (int, error)

WaitExitStatus until process completes and returns exit status.

func (*Process) Write 

func (p *Process) Write(timeout time.Duration, buf []byte) (int, error)

Write writes buf to the process's stdin.

type RunOpts 

type RunOpts struct {
	// Image is the image relative to images/. This will be mangled
	// appropriately, to ensure that only first-party images are used.
	Image string

	// Memory is the memory limit in bytes.
	Memory int

	// Cpus in which to allow execution. ("0", "1", "0-2").
	CpusetCpus string

	// Ports are the ports to be allocated.
	Ports []int

	// WorkDir sets the working directory.
	WorkDir string

	// ReadOnly sets the read-only flag.
	ReadOnly bool

	// Env are additional environment variables.
	Env []string

	// User is the user to use.
	User string

	// Privileged enables privileged mode.
	Privileged bool

	// CapAdd are the extra set of capabilities to add.
	CapAdd []string

	// CapDrop are the extra set of capabilities to drop.
	CapDrop []string

	// Mounts is the list of directories/files to be mounted inside the container.
	Mounts []mount.Mount

	// Links is the list of containers to be connected to the container.
	Links []string
}

RunOpts are options for running a container.

Source Files

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