go: consolidate procman.go into main.go

Single-file structure is idiomatic for small CLI tools that aren't
intended as libraries. At ~320 lines, the code is easily scannable
in one file without jumping between files.

This also improves consistency with mdembed, another pinned repo
with similar single-purpose CLI tool characteristics.

Ordering: imports → const/types → main() → functions by receiver.

Also consolidate test files. This mirrors the source file
consolidation for consistency. At ~270 lines, the tests are
easily scannable in one file.

TestMain stays at the top as test infrastructure, followed by unit
tests, then the integration test.

#2

Co-authored-by: Warp <agent@warp.dev>

Author: croaky

main.go

@@ -9,14 +9,24 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
+	"os/signal"
 	"regexp"
 	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/creack/pty"
 )
 
+const timeout = 5 * time.Second
+
 var (
 	colors     = []int{2, 3, 4, 5, 6, 42, 130, 103, 129, 108}
 	procfileRe = regexp.MustCompile(`^([\w-]+):\s+(.+)$`)
@@ -28,6 +38,30 @@ type procDef struct {
 	cmd  string
 }
 
+// manager handles overall process management
+type manager struct {
+	output      *output
+	procs       []*process
+	procWg      sync.WaitGroup
+	done        chan bool
+	interrupted chan os.Signal
+}
+
+// process represents an individual process to be managed
+type process struct {
+	*exec.Cmd
+	name   string
+	color  int
+	output *output
+}
+
+// output manages the output display of processes
+type output struct {
+	maxNameLength int
+	mutex         sync.Mutex
+	pipes         map[*process]*os.File
+}
+
 func main() {
 	procNames, err := parseArgs(os.Args)
 	if err != nil {
@@ -115,3 +149,172 @@ func parseProcfile(r io.Reader) ([]procDef, error) {
 	}
 	return defs, nil
 }
+
+// setupProcesses creates and initializes processes based on the given procDefs.
+func (mgr *manager) setupProcesses(defs []procDef, procNames []string) error {
+	defMap := make(map[string]string)
+	for _, def := range defs {
+		defMap[def.name] = def.cmd
+	}
+
+	for i, name := range procNames {
+		cmd, ok := defMap[name]
+		if !ok {
+			return fmt.Errorf("No process named %s in Procfile.dev\n", name)
+		}
+
+		proc := &process{
+			Cmd:    exec.Command("/bin/sh", "-c", cmd),
+			name:   name,
+			color:  colors[i%len(colors)],
+			output: mgr.output,
+		}
+		mgr.procs = append(mgr.procs, proc)
+	}
+	return nil
+}
+
+// setupSignalHandling configures handling of interrupt signals.
+func (mgr *manager) setupSignalHandling() {
+	mgr.done = make(chan bool, len(mgr.procs))
+	mgr.interrupted = make(chan os.Signal, 1)
+	signal.Notify(mgr.interrupted, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+}
+
+// runProcess adds the process to the wait group and starts it.
+func (mgr *manager) runProcess(proc *process) {
+	mgr.procWg.Add(1)
+	go func() {
+		defer mgr.procWg.Done()
+		defer func() { mgr.done <- true }()
+		proc.run()
+	}()
+}
+
+// waitForExit waits for all processes to exit or for an interruption signal.
+func (mgr *manager) waitForExit() {
+	select {
+	case <-mgr.done:
+	case <-mgr.interrupted:
+	}
+
+	for _, proc := range mgr.procs {
+		proc.interrupt()
+	}
+
+	select {
+	case <-time.After(timeout):
+	case <-mgr.interrupted:
+	}
+
+	for _, proc := range mgr.procs {
+		proc.kill()
+	}
+}
+
+// running inspects the process to see if it is currently running.
+func (proc *process) running() bool {
+	return proc.Process != nil && proc.ProcessState == nil
+}
+
+// run starts the execution of the process and handles its output.
+func (proc *process) run() {
+	if proc.Process != nil {
+		fmt.Fprintf(os.Stderr, "Process %s already started\n", proc.name)
+		return
+	}
+
+	proc.output.pipeOutput(proc)
+	defer proc.output.closePipe(proc)
+
+	if err := proc.Cmd.Wait(); err != nil {
+		proc.output.writeErr(proc, err)
+	}
+}
+
+// interrupt sends an interrupt signal to a running process.
+func (proc *process) interrupt() {
+	if proc.running() {
+		proc.signal(syscall.SIGINT)
+	}
+}
+
+// kill forcefully stops a running process.
+func (proc *process) kill() {
+	if proc.running() {
+		proc.signal(syscall.SIGKILL)
+	}
+}
+
+// signal sends a specified signal to the process group.
+func (proc *process) signal(sig syscall.Signal) {
+	if err := syscall.Kill(-proc.Process.Pid, sig); err != nil {
+		proc.output.writeErr(proc, err)
+	}
+}
+
+// init initializes the output handler for all processes.
+func (out *output) init(procs []*process) {
+	out.pipes = make(map[*process]*os.File)
+	for _, proc := range procs {
+		if len(proc.name) > out.maxNameLength {
+			out.maxNameLength = len(proc.name)
+		}
+	}
+}
+
+// pipeOutput handles the output piping for a process.
+func (out *output) pipeOutput(proc *process) {
+	ptyFile, err := pty.Start(proc.Cmd)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error opening PTY: %v\n", err)
+		os.Exit(1)
+	}
+
+	out.mutex.Lock()
+	out.pipes[proc] = ptyFile
+	out.mutex.Unlock()
+
+	go func() {
+		scanner := bufio.NewScanner(ptyFile)
+		for scanner.Scan() {
+			out.writeLine(proc, scanner.Bytes())
+		}
+		if err := scanner.Err(); err != nil && !errors.Is(err, os.ErrClosed) {
+			out.writeErr(proc, err)
+		}
+	}()
+}
+
+// closePipe closes the pseudo-terminal associated with the process.
+func (out *output) closePipe(proc *process) {
+	out.mutex.Lock()
+	ptyFile := out.pipes[proc]
+	out.mutex.Unlock()
+
+	if ptyFile != nil {
+		ptyFile.Close()
+	}
+}
+
+// writeLine writes a line of output for the specified process, with color formatting.
+func (out *output) writeLine(proc *process, p []byte) {
+	var buf bytes.Buffer
+	buf.WriteString(fmt.Sprintf("\033[1;38;5;%vm", proc.color))
+	buf.WriteString(proc.name)
+	for i := len(proc.name); i <= out.maxNameLength; i++ {
+		buf.WriteByte(' ')
+	}
+	buf.WriteString("\033[0m| ")
+	buf.Write(p)
+	buf.WriteByte('\n')
+
+	out.mutex.Lock()
+	defer out.mutex.Unlock()
+	buf.WriteTo(os.Stdout)
+}
+
+// writeErr writes an error message for the specified process.
+func (out *output) writeErr(proc *process, err error) {
+	out.writeLine(proc, []byte(fmt.Sprintf("\033[0;31m%v\033[0m", err)))
+}