mirror of
https://github.com/wneessen/logranger.git
synced 2024-10-06 00:55:57 +02:00
Winni Neessen
1aaa9ac247
An unnecessary line break in the server.go file was removed, which was situated between connection error handling and the read loop. Such spacing did not contribute to readability or function, hence impacting the overall code cleanliness.
202 lines
5.5 KiB
Go
202 lines
5.5 KiB
Go
// SPDX-FileCopyrightText: 2023 Winni Neessen <wn@neessen.dev>
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//
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// SPDX-License-Identifier: MIT
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package logranger
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import (
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"errors"
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"fmt"
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"io"
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"log/slog"
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"net"
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"os"
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"strings"
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"sync"
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"time"
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"github.com/wneessen/go-parsesyslog"
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_ "github.com/wneessen/go-parsesyslog/rfc3164"
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_ "github.com/wneessen/go-parsesyslog/rfc5424"
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)
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const (
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// LogErrKey is the keyword used in slog for error messages
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LogErrKey = "error"
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)
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// Server is the main server struct
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type Server struct {
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// conf is a pointer to the config.Config
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conf *Config
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// listener is a listener that satisfies the net.Listener interface
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listener net.Listener
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// log is a pointer to the slog.Logger
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log *slog.Logger
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// parser is a parsesyslog.Parser
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parser parsesyslog.Parser
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// ruleset is a pointer to the ruleset
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ruleset *Ruleset
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// wg is a sync.WaitGroup
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wg sync.WaitGroup
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}
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// New creates a new instance of Server based on the provided Config
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func New(c *Config) *Server {
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s := &Server{
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conf: c,
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}
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s.setLogLevel()
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return s
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}
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// Run starts the logranger Server by creating a new listener using the NewListener
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// method and calling RunWithListener with the obtained listener.
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func (s *Server) Run() error {
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l, err := NewListener(s.conf)
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if err != nil {
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return err
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}
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p, err := parsesyslog.New(s.conf.internal.ParserType)
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if err != nil {
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return fmt.Errorf("failed to initialize syslog parser: %w", err)
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}
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s.parser = p
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rs, err := NewRuleset(s.conf)
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if err != nil {
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return fmt.Errorf("failed to read ruleset: %w", err)
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}
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s.ruleset = rs
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for _, r := range rs.Rule {
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s.log.Debug("found rule", slog.String("ID", r.ID))
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}
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return s.RunWithListener(l)
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}
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// RunWithListener sets the listener for the server and performs some additional
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// tasks for initializing the server. It creates a PID file, writes the process ID
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// to the file, and listens for connections. It returns an error if any of the
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// initialization steps fail.
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func (s *Server) RunWithListener(l net.Listener) error {
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s.listener = l
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// Create PID file
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pf, err := os.Create(s.conf.Server.PIDFile)
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if err != nil {
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s.log.Error("failed to create PID file", LogErrKey, err)
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os.Exit(1)
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}
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pid := os.Getpid()
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s.log.Debug("creating PID file", slog.String("pid_file", pf.Name()),
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slog.Int("pid", pid))
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_, err = pf.WriteString(fmt.Sprintf("%d", pid))
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if err != nil {
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s.log.Error("failed to write PID to PID file", LogErrKey, err)
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_ = pf.Close()
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}
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if err = pf.Close(); err != nil {
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s.log.Error("failed to close PID file", LogErrKey, err)
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}
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// Listen for connections
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s.wg.Add(1)
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go s.Listen()
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return nil
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}
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// Listen handles incoming connections and processes log messages.
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func (s *Server) Listen() {
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defer s.wg.Done()
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s.log.Info("listening for new connections", slog.String("listen_addr", s.listener.Addr().String()))
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for {
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c, err := s.listener.Accept()
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if err != nil {
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s.log.Error("failed to accept new connection", LogErrKey, err)
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continue
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}
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s.log.Debug("accepted new connection",
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slog.String("remote_addr", c.RemoteAddr().String()))
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conn := NewConnection(c)
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s.wg.Add(1)
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go func(co *Connection) {
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s.HandleConnection(co)
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s.wg.Done()
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}(conn)
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}
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}
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// HandleConnection handles a single connection by parsing and processing log messages.
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// It logs debug information about the connection and measures the processing time.
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// It closes the connection when done, and logs any error encountered during the process.
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func (s *Server) HandleConnection(c *Connection) {
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defer func() {
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if err := c.conn.Close(); err != nil {
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s.log.Error("failed to close connection", LogErrKey, err)
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}
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}()
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ReadLoop:
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for {
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if err := c.conn.SetDeadline(time.Now().Add(s.conf.Parser.Timeout)); err != nil {
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s.log.Error("failed to set processing deadline", LogErrKey, err,
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slog.Duration("timeout", s.conf.Parser.Timeout))
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return
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}
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lm, err := s.parser.ParseReader(c.rb)
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if err != nil {
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var ne *net.OpError
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switch {
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case errors.As(err, &ne):
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if s.conf.Log.Extended {
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s.log.Error("network error while processing message", LogErrKey,
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ne.Error())
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}
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return
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case errors.Is(err, io.EOF):
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if s.conf.Log.Extended {
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s.log.Error("message could not be processed", LogErrKey,
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"EOF received")
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}
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return
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default:
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s.log.Error("failed to parse message", LogErrKey, err,
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slog.String("parser_type", s.conf.Parser.Type))
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continue ReadLoop
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}
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}
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s.log.Debug("log message successfully received",
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slog.String("message", lm.Message.String()),
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slog.String("facility", lm.Facility.String()),
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slog.String("severity", lm.Severity.String()),
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slog.Time("server_time", lm.Timestamp))
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}
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}
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// setLogLevel sets the log level based on the value of `s.conf.Log.Level`.
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// It creates a new `slog.HandlerOptions` and assigns the corresponding `slog.Level`
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// based on the value of `s.conf.Log.Level`. If the value is not one of the valid levels,
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// `info` is used as the default level.
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// It then creates a new `slog.JSONHandler` with `os.Stdout` and the handler options.
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// Finally, it creates a new `slog.Logger` with the JSON handler and sets the `s.log` field
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// of the `Server` struct to the logger, with a context value of "logranger".
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func (s *Server) setLogLevel() {
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lo := slog.HandlerOptions{}
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switch strings.ToLower(s.conf.Log.Level) {
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case "debug":
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lo.Level = slog.LevelDebug
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case "info":
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lo.Level = slog.LevelInfo
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case "warn":
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lo.Level = slog.LevelWarn
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case "error":
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lo.Level = slog.LevelError
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default:
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lo.Level = slog.LevelInfo
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}
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lh := slog.NewJSONHandler(os.Stdout, &lo)
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s.log = slog.New(lh).With(slog.String("context", "logranger"))
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}
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