Add profile loading and process execution

internal/process/process.go

@@ -0,0 +1,60 @@
+// Package process runs child commands for ReleaseKit's internal adapters.
+package process
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"sort"
+)
+
+// Invocation describes one child process. Environment values overlay the
+// current process environment for this child only.
+type Invocation struct {
+	Args   []string
+	Dir    string
+	Env    map[string]string
+	Stdout io.Writer
+	Stderr io.Writer
+}
+
+// Run starts the command in the requested directory and waits for it to exit.
+// Errors preserve the underlying exec error, including *exec.ExitError.
+func Run(ctx context.Context, invocation Invocation) error {
+	if len(invocation.Args) == 0 || invocation.Args[0] == "" {
+		return errors.New("process invocation requires a command")
+	}
+
+	command := exec.CommandContext(ctx, invocation.Args[0], invocation.Args[1:]...)
+	command.Dir = invocation.Dir
+	if len(invocation.Env) != 0 {
+		command.Env = append(os.Environ(), environmentEntries(invocation.Env)...)
+	}
+	command.Stdout = invocation.Stdout
+	command.Stderr = invocation.Stderr
+
+	if err := command.Run(); err != nil {
+		if contextErr := ctx.Err(); contextErr != nil {
+			return fmt.Errorf("run %q: %w", invocation.Args[0], contextErr)
+		}
+		return fmt.Errorf("run %q: %w", invocation.Args[0], err)
+	}
+	return nil
+}
+
+func environmentEntries(environment map[string]string) []string {
+	keys := make([]string, 0, len(environment))
+	for key := range environment {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	entries := make([]string, 0, len(keys))
+	for _, key := range keys {
+		entries = append(entries, key+"="+environment[key])
+	}
+	return entries
+}