refactor: improve Go best practices compliance

- Add explicit interface satisfaction checks (var _ Interface = (*Type)(nil)) for compile-time verification:
  - TurboWriter implementations (DirectTurboWriter, TurboChannelWriter)
  - Processor implementations (GrepLineProcessor, ChannellessLineProcessor)
  - Parser implementations (genericParser, csvParser, genericKVParser, custom parsers, mimecastParser)
  - Logger implementations (file, stdout)
  - Handler implementations (ServerHandler, ClientHandler)
  - Connector implementations (Serverless, ServerConnection)
  - SSH callback implementations (KnownHostsCallback)

- Improve error handling with context wrapping (%w):
  - SSH operations: GeneratePrivateRSAKey, Agent
  - Query parsing: Query.parse
  - SSH client connections: dial, session, handle methods

- Fix receiver consistency:
  - Convert Query.String() from value to pointer receiver
  - Convert Outfile.String() from value to pointer receiver
  - Convert all KnownHostsCallback methods to pointer receivers
  - Convert mapCommand.Start() to pointer receiver

- Reorganize file structure for better clarity:
  - internal/io/dlog/dlog.go: Move type definition before public functions
  - internal/mapr/token.go: Reorganize helper functions after public ones

- Add documentation comments:
  - Query.String() method
  - Outfile.String() method
  - Regex.String() method
  - Improve config variable documentation

All unit tests and integration tests pass.

Amp-Thread-ID: https://ampcode.com/threads/T-019c0b08-0eeb-705d-a1f7-31bb764b659a
Co-authored-by: Amp <amp@ampcode.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/internal/ssh/ssh.go b/internal/ssh/ssh.go
index 9c2dcb8..32e01b3 100644
--- a/internal/ssh/ssh.go
+++ b/internal/ssh/ssh.go
@@ -21,11 +21,10 @@ import (
 func GeneratePrivateRSAKey(size int) (*rsa.PrivateKey, error) {
 	privateKey, err := rsa.GenerateKey(rand.Reader, size)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to generate RSA key: %w", err)
 	}
-	err = privateKey.Validate()
-	if err != nil {
-		return nil, err
+	if err = privateKey.Validate(); err != nil {
+		return nil, fmt.Errorf("failed to validate generated RSA key: %w", err)
 	}
 	return privateKey, nil
 }
@@ -46,12 +45,12 @@ func EncodePrivateKeyToPEM(privateKey *rsa.PrivateKey) []byte {
 func Agent() (gossh.AuthMethod, error) {
 	sshAgent, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to connect to SSH agent: %w", err)
 	}
 	agentClient := agent.NewClient(sshAgent)
 	keys, err := agentClient.List()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to list SSH agent keys: %w", err)
 	}
 	for i, key := range keys {
 		dlog.Common.Debug("Public key", i, key)