feat(gl): scaffold general ledger grpc service

infrastructure/config/config.go

@@ -0,0 +1,81 @@
+// Package config owns GL configuration loading and validation.
+package config
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/knadh/koanf/parsers/toml"
+	"github.com/knadh/koanf/providers/file"
+	"github.com/knadh/koanf/v2"
+)
+
+type Config struct {
+	Environment string         `koanf:"environment"`
+	GRPC        GRPCConfig     `koanf:"grpc"`
+	Database    DatabaseConfig `koanf:"database"`
+}
+
+type GRPCConfig struct {
+	Host            string        `koanf:"host"`
+	Port            int           `koanf:"port"`
+	ShutdownTimeout time.Duration `koanf:"shutdown-timeout"`
+}
+
+type DatabaseConfig struct {
+	Host     string `koanf:"host"`
+	Port     int    `koanf:"port"`
+	Name     string `koanf:"name"`
+	User     string `koanf:"user"`
+	Password string `koanf:"password"`
+	SSLMode  string `koanf:"ssl-mode"`
+}
+
+func Load(path string) (*Config, error) {
+	cfg := &Config{
+		Environment: "local",
+		GRPC: GRPCConfig{
+			Host:            "0.0.0.0",
+			Port:            8500,
+			ShutdownTimeout: 10 * time.Second,
+		},
+		Database: DatabaseConfig{
+			Host:    "127.0.0.1",
+			Port:    5432,
+			Name:    "gl_db",
+			User:    "postgres",
+			SSLMode: "disable",
+		},
+	}
+
+	k := koanf.New(".")
+	if err := k.Load(file.Provider(path), toml.Parser()); err != nil {
+		return nil, fmt.Errorf("load config: %w", err)
+	}
+	if err := k.Unmarshal("", cfg); err != nil {
+		return nil, fmt.Errorf("decode config: %w", err)
+	}
+	if err := cfg.Validate(); err != nil {
+		return nil, err
+	}
+	return cfg, nil
+}
+
+func (c *Config) Validate() error {
+	if c.GRPC.Host == "" {
+		return fmt.Errorf("grpc host is required")
+	}
+	if c.GRPC.Port < 0 || c.GRPC.Port > 65535 {
+		return fmt.Errorf("grpc port must be between 0 and 65535")
+	}
+	if c.GRPC.ShutdownTimeout <= 0 {
+		return fmt.Errorf("grpc shutdown timeout must be positive")
+	}
+	if c.Database.Host == "" || c.Database.Name == "" || c.Database.User == "" {
+		return fmt.Errorf("database host, name, and user are required")
+	}
+	if c.Database.Port < 1 || c.Database.Port > 65535 {
+		return fmt.Errorf("database port must be between 1 and 65535")
+	}
+	return nil
+}

infrastructure/config/config_test.go

@@ -0,0 +1,46 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestLoadUsesDefaultsAndOverrides(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "gl.toml")
+	contents := []byte("[grpc]\nport = 0\nshutdown-timeout = \"3s\"\n")
+	if err := os.WriteFile(path, contents, 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.GRPC.Port != 0 || cfg.GRPC.ShutdownTimeout != 3*time.Second {
+		t.Fatalf("unexpected grpc config: %+v", cfg.GRPC)
+	}
+	if cfg.Database.Name != "gl_db" || cfg.Database.Port != 5432 {
+		t.Fatalf("unexpected database defaults: %+v", cfg.Database)
+	}
+}
+
+func TestLoadRejectsInvalidConfiguration(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "gl.toml")
+	if err := os.WriteFile(path, []byte("[grpc]\nshutdown-timeout = \"0s\"\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := Load(path); err == nil {
+		t.Fatal("expected validation error")
+	}
+}
+
+func TestLoadReturnsMissingFileError(t *testing.T) {
+	if _, err := Load(filepath.Join(t.TempDir(), "missing.toml")); err == nil {
+		t.Fatal("expected missing file error")
+	}
+}