87b16ca41c
Add Program to the process package as a lightweight tool-finder and runner. Find() resolves a binary via exec.LookPath (wrapping ErrProgramNotFound), Run() and RunDir() execute the binary and return trimmed combined output. Includes 7 tests covering happy paths, error paths, and the errors.Is contract. Co-Authored-By: Virgil <virgil@lethean.io>
68 lines
2 KiB
Go
68 lines
2 KiB
Go
package process
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import (
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"bytes"
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"context"
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"fmt"
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"os/exec"
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"strings"
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coreerr "forge.lthn.ai/core/go-log"
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)
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// ErrProgramNotFound is returned when Find cannot locate the binary on PATH.
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// Callers may use errors.Is to detect this condition.
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var ErrProgramNotFound = coreerr.E("", "program: binary not found in PATH", nil)
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// Program represents a named executable located on the system PATH.
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// Create one with a Name, call Find to resolve its path, then Run or RunDir.
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type Program struct {
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// Name is the binary name (e.g. "go", "node", "git").
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Name string
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// Path is the absolute path resolved by Find.
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// If empty, Run and RunDir fall back to Name for OS PATH resolution.
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Path string
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}
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// Find resolves the program's absolute path using exec.LookPath.
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// Returns ErrProgramNotFound (wrapped) if the binary is not on PATH.
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func (p *Program) Find() error {
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if p.Name == "" {
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return coreerr.E("Program.Find", "program name is empty", nil)
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}
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path, err := exec.LookPath(p.Name)
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if err != nil {
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return coreerr.E("Program.Find", fmt.Sprintf("%q: not found in PATH", p.Name), ErrProgramNotFound)
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}
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p.Path = path
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return nil
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}
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// Run executes the program with args in the current working directory.
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// Returns trimmed combined stdout+stderr output and any error.
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func (p *Program) Run(ctx context.Context, args ...string) (string, error) {
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return p.RunDir(ctx, "", args...)
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}
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// RunDir executes the program with args in dir.
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// Returns trimmed combined stdout+stderr output and any error.
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// If dir is empty, the process inherits the caller's working directory.
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func (p *Program) RunDir(ctx context.Context, dir string, args ...string) (string, error) {
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binary := p.Path
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if binary == "" {
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binary = p.Name
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}
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var out bytes.Buffer
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cmd := exec.CommandContext(ctx, binary, args...)
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cmd.Stdout = &out
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cmd.Stderr = &out
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if dir != "" {
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cmd.Dir = dir
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}
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if err := cmd.Run(); err != nil {
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return strings.TrimSpace(out.String()), coreerr.E("Program.RunDir", fmt.Sprintf("%q: command failed", p.Name), err)
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}
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return strings.TrimSpace(out.String()), nil
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}
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