go-process/specs/exec/RFC.md

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# exec
**Import:** `dappco.re/go/core/process/exec`
**Files:** 3
## Types
### `Options`
`struct`
Command execution options used by `Cmd`.
Fields:
- `Dir string`: Working directory.
- `Env []string`: Environment entries appended to `os.Environ()` when non-empty.
- `Stdin io.Reader`: Reader assigned to command stdin.
- `Stdout io.Writer`: Writer assigned to command stdout.
- `Stderr io.Writer`: Writer assigned to command stderr.
### `Cmd`
`struct`
Wrapped command with chainable configuration methods.
Exported fields:
- None.
### `Logger`
`interface`
Command-execution logger.
Methods:
- `Debug(msg string, keyvals ...any)`: Logs a debug-level message.
- `Error(msg string, keyvals ...any)`: Logs an error-level message.
### `NopLogger`
`struct`
No-op `Logger` implementation.
Exported fields:
- None.
## Functions
### Package Functions
- `func Command(ctx context.Context, name string, args ...string) *Cmd`: Returns a `Cmd` for the supplied context, executable name, and arguments.
- `func RunQuiet(ctx context.Context, name string, args ...string) error`: Runs a command with stderr captured into a buffer and returns `core.E("exec.run_quiet", core.Trim(stderr.String()), err)` on failure.
- `func SetDefaultLogger(l Logger)`: Sets the package-level default logger. Passing `nil` replaces it with `NopLogger`.
- `func DefaultLogger() Logger`: Returns the package-level default logger.
### `Cmd` Methods
- `func (c *Cmd) WithDir(dir string) *Cmd`: Sets `Options.Dir` and returns the same command.
- `func (c *Cmd) WithEnv(env []string) *Cmd`: Sets `Options.Env` and returns the same command.
- `func (c *Cmd) WithStdin(r io.Reader) *Cmd`: Sets `Options.Stdin` and returns the same command.
- `func (c *Cmd) WithStdout(w io.Writer) *Cmd`: Sets `Options.Stdout` and returns the same command.
- `func (c *Cmd) WithStderr(w io.Writer) *Cmd`: Sets `Options.Stderr` and returns the same command.
- `func (c *Cmd) WithLogger(l Logger) *Cmd`: Sets a command-specific logger and returns the same command.
- `func (c *Cmd) Run() error`: Prepares the underlying `exec.Cmd`, logs `"executing command"`, runs it, and wraps failures with `wrapError("exec.cmd.run", ...)`.
- `func (c *Cmd) Output() ([]byte, error)`: Prepares the underlying `exec.Cmd`, logs `"executing command"`, returns stdout bytes, and wraps failures with `wrapError("exec.cmd.output", ...)`.
- `func (c *Cmd) CombinedOutput() ([]byte, error)`: Prepares the underlying `exec.Cmd`, logs `"executing command"`, returns combined stdout and stderr, and wraps failures with `wrapError("exec.cmd.combined_output", ...)`.
### `NopLogger` Methods
- `func (NopLogger) Debug(string, ...any)`: Discards the message.
- `func (NopLogger) Error(string, ...any)`: Discards the message.