Documentation
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Overview ¶
Package cmd provides functionality used to execute commands inside of containers or UVMs, and to connect an upstream client to those commands for handling in/out/err IO.
Index ¶
- func ExecInShimHost(ctx context.Context, req *shimdiag.ExecProcessRequest) (int, error)
- func ExecInUvm(ctx context.Context, vm *uvm.UtilityVM, req *shimdiag.ExecProcessRequest) (int, error)
- type Cmd
- type ExitError
- type ExitState
- type UpstreamIO
- func NewBinaryIO(ctx context.Context, id string, uri *url.URL) (_ UpstreamIO, err error)
- func NewNpipeIO(ctx context.Context, stdin, stdout, stderr string, terminal bool) (_ UpstreamIO, err error)
- func NewUpstreamIO(ctx context.Context, id string, stdout string, stderr string, stdin string, ...) (UpstreamIO, error)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ExecInShimHost ¶
ExecInShimHost is a helper function used to execute commands specified in `req` in the shim's hosting system.
Types ¶
type Cmd ¶
type Cmd struct {
// Host is the process host in which to launch the process.
Host cow.ProcessHost
// The OCI spec for the process.
Spec *specs.Process
// Standard IO streams to relay to/from the process.
Stdin io.Reader
Stdout io.Writer
Stderr io.Writer
// Log provides a logrus entry to use in logging IO copying status.
Log *logrus.Entry
// Context provides a context that terminates the process when it is done.
Context context.Context
// CopyAfterExitTimeout is the amount of time after process exit we allow the
// stdout, stderr relays to continue before forcibly closing them if not
// already completed. This is primarily a safety step against the HCS when
// it fails to send a close on the stdout, stderr pipes when the process
// exits and blocks the relay wait groups forever.
CopyAfterExitTimeout time.Duration
// Process is filled out after Start() returns.
Process cow.Process
// ExitState is filled out after Wait() (or Run() or Output()) completes.
ExitState *ExitState
// contains filtered or unexported fields
}
Cmd represents a command being prepared or run in a process host.
func Command ¶
func Command(host cow.ProcessHost, name string, arg ...string) *Cmd
Command makes a Cmd for a given command and arguments.
func CommandContext ¶
CommandContext makes a Cmd for a given command and arguments. After it is launched, the process is killed when the context becomes done.
func (*Cmd) Output ¶
Output runs a command via Run and collects its stdout into a buffer, which it returns.
type ExitError ¶
type ExitError struct {
*ExitState
}
ExitError is used when a process exits with a non-zero exit code.
type ExitState ¶
type ExitState struct {
// contains filtered or unexported fields
}
ExitState contains whether a process has exited and with which exit code.
type UpstreamIO ¶
type UpstreamIO interface {
// Close closes all open io.
//
// This call is idempotent and safe to call multiple times.
Close(ctx context.Context)
// CloseStdin closes just `Stdin()` if open.
//
// This call is idempotent and safe to call multiple times.
CloseStdin(ctx context.Context)
// Stdin returns the open `stdin` reader. If `stdin` was never opened this
// will return `nil`.
Stdin() io.Reader
// StdinPath returns the original path used to open the `Stdin()` reader.
StdinPath() string
// Stdout returns the open `stdout` writer. If `stdout` was never opened
// this will return `nil`.
Stdout() io.Writer
// StdoutPath returns the original path used to open the `Stdout()` writer.
StdoutPath() string
// Stderr returns the open `stderr` writer. If `stderr` was never opened
// this will return `nil`.
Stderr() io.Writer
// StderrPath returns the original path used to open the `Stderr()` writer.
StderrPath() string
// Terminal returns `true` if the connection is emulating a terminal. If
// `true` `Stderr()` will always return `nil` and `StderrPath()` will always
// return `""`.
Terminal() bool
}
UpstreamIO is an interface describing the IO to connect to above the shim. Depending on the callers settings there may be no opened IO.
func NewBinaryIO ¶
NewBinaryIO runs a custom binary process for pluggable shim logging driver.
Container's IO will be redirected to the logging driver via named pipes, which are passed as "CONTAINER_STDOUT", "CONTAINER_STDERR" environment variables. The logging driver MUST dial a wait pipe passed via "CONTAINER_WAIT" environment variable AND CLOSE it to indicate that it's ready to consume the IO. For customer's convenience container ID and namespace are also passed via "CONTAINER_ID" and "CONTAINER_NAMESPACE".
The path to the logging driver can be provided via a URL's host/path. Additional arguments can be passed to the logger via URL query params
func NewNpipeIO ¶
func NewNpipeIO(ctx context.Context, stdin, stdout, stderr string, terminal bool) (_ UpstreamIO, err error)
NewNpipeIO creates connected upstream io. It is the callers responsibility to validate that `if terminal == true`, `stderr == ""`.
func NewUpstreamIO ¶
func NewUpstreamIO(ctx context.Context, id string, stdout string, stderr string, stdin string, terminal bool) (UpstreamIO, error)
NewUpstreamIO returns an UpstreamIO instance. Currently we only support named pipes and binary logging driver for container IO. When using binary logger `stdout` and `stderr` are assumed to be the same and the value of `stderr` is completely ignored.
Source Files