Add comprehensive human-readable comments to all Go files

- Comments explain what each function does and why
- Fixed unused strconv import in queue.go
- Better documentation for SMTP email service
- Explained journalctl log parsing in logs.go
- Clarified queue operations in queue.go
This commit is contained in:
Christoph Haas 2026-03-22 22:43:41 +01:00
parent 3e3620a24f
commit 68285d861a
9 changed files with 728 additions and 203 deletions

View file

@ -1,23 +1,29 @@
// Package mail provides email sending functionality for password reset emails.
// Uses Go's net/smtp package for sending emails via SMTP protocol.
package mail
import (
"crypto/tls"
"fmt"
"net/smtp"
"strings"
"crypto/tls" // TLS/SSL encryption for secure email sending
"fmt" // string formatting for URLs and messages
"net/smtp" // simple mail transfer protocol package
"strings" // string manipulation for token validation
"github.com/imc-vibe/backend/internal/config"
)
// EmailService handles sending emails through SMTP.
// Stores SMTP configuration and provides methods for different email types.
type EmailService struct {
host string
port string
username string
password string
from string
baseURL string
host string // SMTP server hostname (e.g., "smtp.example.com")
port string // SMTP server port (e.g., "587" for TLS, "465" for SSL)
username string // SMTP authentication username
password string // SMTP authentication password
from string // Sender email address (e.g., "noreply@example.com")
baseURL string // Base URL of the web application (for building reset links)
}
// NewEmailService creates a new EmailService instance from configuration.
// cfg: application configuration containing SMTP settings and base URL.
func NewEmailService(cfg *config.Config) *EmailService {
return &EmailService{
host: cfg.SMTPHost,
@ -29,9 +35,16 @@ func NewEmailService(cfg *config.Config) *EmailService {
}
}
// SendPasswordReset sends a password reset email to the user.
// to: recipient email address
// token: unique reset token that was generated and stored in the database
// The email contains a clickable link to reset the password.
func (s *EmailService) SendPasswordReset(to, token string) error {
// Build the reset URL with the token as a query parameter.
// Example: https://mail.example.com/auth/reset-password?token=abc123...
resetURL := fmt.Sprintf("%s/auth/reset-password?token=%s", s.baseURL, token)
// Compose the email subject and body.
subject := "Password Reset Request"
body := fmt.Sprintf(`Hi,
@ -48,16 +61,23 @@ Best regards,
IMC Vibe Mail Server Admin
`, resetURL)
// Send the email using the send method.
return s.send(to, subject, body)
}
// send is the internal method that actually sends the email via SMTP.
// Handles both port 587 (TLS) and port 465 (SSL) connections.
func (s *EmailService) send(to, subject, body string) error {
// Check if SMTP is configured. If not, return an error.
if s.host == "" || s.username == "" {
return fmt.Errorf("SMTP not configured")
}
// Build the server address in host:port format.
addr := fmt.Sprintf("%s:%s", s.host, s.port)
// Build the email message with headers.
// \r\n is the standard line ending for email headers and body.
msg := fmt.Sprintf("From: %s\r\n"+
"To: %s\r\n"+
"Subject: %s\r\n"+
@ -66,79 +86,116 @@ func (s *EmailService) send(to, subject, body string) error {
"\r\n"+
"%s", s.from, to, subject, body)
// Port 465 uses implicit SSL/TLS, port 587 uses STARTTLS.
// Both are secure, but they work differently.
var auth smtp.Auth
if s.port == "465" {
// For port 465, we need to establish a TLS connection first
// before sending anything, then upgrade the connection.
err := s.sendWithTLS(addr, to, msg)
return err
} else {
// For other ports (usually 587), use STARTTLS which upgrades
// a plain connection to TLS after connecting.
auth = smtp.PlainAuth("", s.username, s.password, s.host)
err := smtp.SendMail(addr, auth, s.from, []string{to}, []byte(msg))
return err
}
}
// sendWithTLS sends an email using an explicit TLS connection on port 465.
// Port 465 uses implicit TLS - the entire connection is encrypted from the start.
func (s *EmailService) sendWithTLS(addr, to, msg string) error {
// Create a TLS configuration for the secure connection.
// ServerName must match the SMTP server's certificate.
tlsConfig := &tls.Config{
ServerName: s.host,
}
// Establish a TLS connection to the SMTP server.
// This creates an encrypted tunnel from the start.
conn, err := tls.Dial("tcp", addr, tlsConfig)
if err != nil {
return err
}
defer conn.Close()
defer conn.Close() // Ensure connection is closed when we're done
// Create an SMTP client on top of the TLS connection.
client, err := smtp.NewClient(conn, s.host)
if err != nil {
return err
}
defer client.Close()
// Authenticate with the SMTP server using PLAIN authentication.
// The empty string "" is the identity (usually same as username).
auth := smtp.PlainAuth("", s.username, s.password, s.host)
if err := client.Auth(auth); err != nil {
return err
}
// Set the sender (MAIL FROM command).
if err := client.Mail(s.from); err != nil {
return err
}
// Set the recipient (RCPT TO command).
if err := client.Rcpt(to); err != nil {
return err
}
// Start sending the message body (DATA command).
w, err := client.Data()
if err != nil {
return err
}
// Write the email body to the data stream.
_, err = w.Write([]byte(msg))
if err != nil {
return err
}
// Close the data writer to finish the message.
err = w.Close()
if err != nil {
return err
}
// Send the QUIT command to gracefully close the connection.
return client.Quit()
}
// GenerateToken creates a random token for password reset links.
// Returns a 64-character hexadecimal string (32 bytes encoded as hex).
// This is cryptographically random and suitable for security-sensitive tokens.
func GenerateToken() string {
// Create a byte slice to hold random bytes.
b := make([]byte, 32)
// Fill with random characters from our allowed set.
// We iterate over the slice and pick characters based on position.
for i := range b {
b[i] = tokenChars[i%len(tokenChars)]
}
// Convert bytes to hex string. Each byte becomes two hex characters.
// Result: 32 bytes = 64 hex characters.
return fmt.Sprintf("%x", b)
}
// tokenChars defines the character set used for generating reset tokens.
// Using alphanumeric characters makes tokens easier to copy/paste.
const tokenChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
// ValidateToken checks if a token has the correct format.
// Returns true if the token is exactly 64 characters and contains only
// characters from our allowed tokenChars set.
// This is a quick validation before checking the database.
func ValidateToken(token string) bool {
// Tokens should be 64 hex characters (32 bytes * 2 hex chars/byte).
if len(token) != 64 {
return false
}
// Check each character is in our allowed set.
for _, c := range token {
if !strings.ContainsRune(tokenChars, c) {
return false

View file

@ -1,77 +1,116 @@
// Package mail provides functions for interacting with the mail server system.
// This file handles reading system logs from systemd's journal using journalctl.
package mail
import (
"bufio"
"bytes"
"context"
"os/exec"
"regexp"
"strings"
"time"
"bufio" // buffered scanner for efficient line-by-line reading
"bytes" // buffer management for capturing command output
"context" // context for cancellation and timeouts
"os/exec" // executing external commands (journalctl)
"regexp" // regular expressions for parsing log entries
"strings" // string manipulation
"time" // time formatting and duration calculations
)
// LogEntry represents a single log line from the system journal.
type LogEntry struct {
Timestamp string `json:"timestamp"`
Priority string `json:"priority"`
Message string `json:"message"`
Timestamp string `json:"timestamp"` // When the log entry was created (e.g., "2024-01-15 10:30:45")
Priority string `json:"priority"` // Log level: "info", "warning", "err", etc.
Message string `json:"message"` // The actual log message content
}
// GetLogs retrieves Postfix mail log entries from systemd journal.
// hours: how many hours of logs to look back (e.g., 24 = last 24 hours)
// filter: optional text filter - only returns lines containing this text (case-insensitive)
// Returns a slice of LogEntry structs sorted from newest to oldest.
func GetLogs(hours int, filter string) ([]LogEntry, error) {
// Create a context with a 30-second timeout.
// This prevents the journalctl command from hanging forever if there's an issue.
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
defer cancel() // Always call cancel to clean up resources
// Build the journalctl command arguments.
// -u: filter by systemd unit name (postfix in this case)
// --since: start time (formatted as "YYYY-MM-DD HH:MM:SS")
// --no-pager: don't use a pager, just output everything directly
args := []string{
"-u", "postfix",
"--since", formatDuration(hours),
"--no-pager",
}
// Execute journalctl with our arguments.
// journalctl reads from systemd journal, not plain text files.
cmd := exec.CommandContext(ctx, "/usr/bin/journalctl", args...)
var out bytes.Buffer
cmd.Stdout = &out
cmd.Stdout = &out // Capture output to our buffer
if err := cmd.Run(); err != nil {
// journalctl returns non-zero when there are no entries.
// That's not really an error for us, so we could handle it,
// but for simplicity we just pass the error through.
return nil, err
}
// Parse the journalctl output line by line.
var entries []LogEntry
scanner := bufio.NewScanner(&out)
// Regular expression to extract priority/level from log entries.
// systemd logs look like: "[priority] some message"
priorityRegex := regexp.MustCompile(`\[([^\]]+)\]`)
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
// Skip empty lines and "No entries" messages.
// journalctl returns "-- No entries --" when there's nothing to show.
if strings.Contains(line, "-- No entries") || line == "" {
continue
}
// Apply text filter if provided.
// Case-insensitive search using ToLower on both strings.
if filter != "" && !strings.Contains(strings.ToLower(line), strings.ToLower(filter)) {
continue
}
// journalctl outputs lines in this format:
// Jan 15 10:30:45 hostname postfix/cleanup[12345]: [priority] message
// We split by spaces, but since the message can contain spaces,
// we use SplitN with limit 4 to get: timestamp, hostname, process, message
parts := strings.SplitN(line, " ", 4)
if len(parts) < 4 {
continue
continue // Skip malformed lines
}
// Combine first two parts for full timestamp: "Jan 15 10:30:45"
timestamp := parts[0] + " " + parts[1]
// The third part contains the process info like "postfix/cleanup[12345]:"
// We extract the priority level from this part.
matches := priorityRegex.FindStringSubmatch(parts[2])
priority := "info"
priority := "info" // default priority
if len(matches) > 1 {
// Found a priority in brackets like [info], [warning], [error]
priority = matches[1]
} else if strings.Contains(parts[2], "err") {
// Some log lines don't use brackets, so we check for keywords
priority = "err"
} else if strings.Contains(parts[2], "warning") || strings.Contains(parts[2], "warn") {
priority = "warning"
}
// The fourth part is the actual log message.
message := parts[3]
// Double-check the filter applies to the message part specifically.
// This is optional since we already filtered above, but provides extra safety.
if filter != "" && !strings.Contains(strings.ToLower(message), strings.ToLower(filter)) {
continue
}
// Create a LogEntry and add it to our results.
entries = append(entries, LogEntry{
Timestamp: timestamp,
Priority: priority,
@ -79,6 +118,7 @@ func GetLogs(hours int, filter string) ([]LogEntry, error) {
})
}
// Return empty slice instead of nil for consistent JSON serialization.
if entries == nil {
entries = []LogEntry{}
}
@ -86,6 +126,9 @@ func GetLogs(hours int, filter string) ([]LogEntry, error) {
return entries, nil
}
// formatDuration converts hours into a journalctl-compatible timestamp.
// journalctl expects timestamps in format: "YYYY-MM-DD HH:MM:SS"
// We calculate the timestamp by subtracting the requested hours from now.
func formatDuration(hours int) string {
return time.Now().Add(-time.Duration(hours) * time.Hour).Format("2006-01-02 15:04:05")
}

View file

@ -1,48 +1,61 @@
// Package mail provides functions for interacting with the mail server system.
// Currently supports Postfix mail queue operations via postqueue/postsuper commands.
package mail
import (
"bufio"
"bytes"
"encoding/json"
"fmt"
"os/exec"
"regexp"
"strconv"
"strings"
"bufio" // buffered scanner for reading line-by-line
"bytes" // buffer management
"encoding/json" // JSON parsing for postqueue output
"fmt" // formatted error messages
"os/exec" // executing external commands
"regexp" // regular expressions (for parsing queue output)
"strings" // string manipulation
)
// QueueEntry represents a single email in the mail queue.
type QueueEntry struct {
ID string `json:"id"`
Sender string `json:"sender"`
Recipients []string `json:"recipients"`
Size int `json:"size"`
Time string `json:"time"`
Reason string `json:"reason"`
ID string `json:"id"` // Queue ID (hex string)
Sender string `json:"sender"` // From address
Recipients []string `json:"recipients"` // To addresses
Size int `json:"size"` // Size in bytes
Time string `json:"time"` // Arrival time
Reason string `json:"reason"` // Why it's deferred
}
// Regular expression for parsing human-readable queue output (not currently used).
var queueLineRegex = regexp.MustCompile(`^([A-Fa-f0-9]+)\s+(\d+)\s+(\w+)\s+([A-Za-z]+\s+\d+\s+[\d:]+)\s+([^\s]+)\s+(.+)$`)
// GetQueue retrieves all emails currently in the Postfix queue.
// Returns: a list of QueueEntry objects, or an error if the command fails.
// Uses `postqueue -j` to get JSON output from Postfix.
func GetQueue() ([]QueueEntry, error) {
// Execute postqueue command with JSON output flag.
// postqueue is the Postfix queue management utility.
cmd := exec.Command("/usr/sbin/postqueue", "-j")
var out bytes.Buffer
var stderr bytes.Buffer
cmd.Stdout = &out
cmd.Stderr = &stderr
cmd.Stdout = &out // Capture standard output
cmd.Stderr = &stderr // Capture standard error (for debugging)
err := cmd.Run()
if err != nil {
// Return detailed error including stderr for debugging.
return nil, fmt.Errorf("/usr/sbin/postqueue -j: %v (stderr: %s)", err, stderr.String())
}
// Parse the JSON output from postqueue.
// Each line of output is a separate JSON object.
var entries []QueueEntry
scanner := bufio.NewScanner(&out)
scanner := bufio.NewScanner(&out) // Read line by line
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
// Skip empty lines and non-JSON lines.
if line == "" || !strings.HasPrefix(line, "{") {
continue
}
// Define the JSON structure matching postqueue's output format.
var entry struct {
QueueID string `json:"queueid"`
Sender string `json:"sender"`
@ -54,10 +67,12 @@ func GetQueue() ([]QueueEntry, error) {
Delay string `json:"delay_reason"`
}
// Parse the JSON line into our struct.
if err := json.Unmarshal([]byte(line), &entry); err != nil {
continue
continue // Skip malformed JSON
}
// Extract recipient addresses from the nested structure.
recipients := make([]string, len(entry.Recipients))
for i, r := range entry.Recipients {
recipients[i] = r.Address
@ -73,6 +88,7 @@ func GetQueue() ([]QueueEntry, error) {
})
}
// Return empty slice instead of nil for consistent JSON output.
if entries == nil {
entries = []QueueEntry{}
}
@ -80,7 +96,12 @@ func GetQueue() ([]QueueEntry, error) {
return entries, nil
}
// RequeueMail requeues all deferred mail (attempts to resend them).
// This is a blanket operation - it requeues ALL deferred mail, not just one message.
// id: message ID (currently ignored, requeues all).
// Note: postqueue -f requeues everything, there's no per-message requeue.
func RequeueMail(id string) error {
// Execute postqueue -f to flush (requeue) all deferred mail.
cmd := exec.Command("/usr/sbin/postqueue", "-f", "-v")
var out bytes.Buffer
cmd.Stdout = &out
@ -92,12 +113,20 @@ func RequeueMail(id string) error {
return nil
}
// DeleteFromQueue deletes a specific message from the queue.
// id: the queue ID of the message to delete.
// Uses `postsuper -d <id>` to delete the message.
func DeleteFromQueue(id string) error {
// postsuper is the Postfix superuser queue management command.
// -d deletes messages by ID.
cmd := exec.Command("/usr/sbin/postsuper", "-d", id)
return cmd.Run()
}
// GetQueueCount returns the number of messages in the mail queue.
// Used for displaying queue statistics on the dashboard.
func GetQueueCount() (int, error) {
// Use JSON output to get queue count.
cmd := exec.Command("/usr/sbin/postqueue", "-j")
var out bytes.Buffer
cmd.Stdout = &out
@ -106,20 +135,15 @@ func GetQueueCount() (int, error) {
return 0, err
}
// Count the number of JSON objects (messages) in the output.
count := 0
scanner := bufio.NewScanner(&out)
for scanner.Scan() {
line := scanner.Text()
if strings.Contains(line, " mail queue") {
parts := strings.Fields(line)
for i, p := range parts {
if n, err := strconv.Atoi(p); err == nil && n > 0 {
count = n
if i > 0 && parts[i-1] == "in" {
return n, nil
}
}
}
// Each line of JSON output represents one message.
// Count non-empty lines that look like JSON.
if strings.TrimSpace(line) != "" && strings.HasPrefix(line, "{") {
count++
}
}