subproc

Documentation

Overview

Package subproc provides helper utilities for executing the Nomad binary as a child process of the Nomad agent.

The main entrypoint is the Do function, in which the given MainFunc will be executed as a sub-process if the first argument matches the subcommand.

Context can be used to create a context.Context object with a given timeout, and is expected to be used in conjunction with SetExpiration which uses the context's termination to forcefully terminate the child process if it has not exited by itself.

Index

• Constants
• func Context(timeout time.Duration) (context.Context, context.CancelFunc)
• func Do(name string, f MainFunc)
• func Log(r io.Reader, f func(msg string, args ...any))
• func Print(format string, args ...any)
• func Self() string
• func SetExpiration(ctx context.Context)
• type MainFunc

Constants

const (
	// ExitSuccess indicates the subprocess completed successfully.
	ExitSuccess = iota

	// ExitFailure indicates the subprocess terminated unsuccessfully.
	ExitFailure

	// ExitTimeout indicates the subprocess timed out before completion.
	ExitTimeout
)

Functions

func Context

func Context(timeout time.Duration) (context.Context, context.CancelFunc)

Context creates a context setup with the given timeout.

func Do

func Do(name string, f MainFunc)

Do f if nomad was launched as, "nomad [name]". This process will exit without running any other part of Nomad.

func Log

func Log(r io.Reader, f func(msg string, args ...any))

Log the given output to the logger.

r should be a buffer containing output (typically combined stdin + stdout) f should be an HCLogger Print method (e.g. log.Debug)

func Print

func Print(format string, args ...any)

Print the given message to standard error.

func Self

func Self() string

Self returns the path to the executable of this process.

func SetExpiration

func SetExpiration(ctx context.Context)

SetExpiration is used to ensure the process terminates, once ctx is complete. A short grace period is added to allow any cleanup to happen first.

Types

type MainFunc

type MainFunc func() int

MainFunc is the function that runs for this sub-process.

The return value is a process exit code.