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package handlers
import (
"context"
"path/filepath"
"strings"
"sync"
"time"
"github.com/mimecast/dtail/internal/io/fs"
"github.com/mimecast/dtail/internal/io/logger"
"github.com/mimecast/dtail/internal/lcontext"
"github.com/mimecast/dtail/internal/omode"
"github.com/mimecast/dtail/internal/regex"
)
type readCommand struct {
server *ServerHandler
mode omode.Mode
}
func newReadCommand(server *ServerHandler, mode omode.Mode) *readCommand {
return &readCommand{
server: server,
mode: mode,
}
}
func (r *readCommand) Start(ctx context.Context, lContext lcontext.LContext, argc int, args []string, retries int) {
re := regex.NewNoop()
if argc >= 4 {
deserializedRegex, err := regex.Deserialize(strings.Join(args[2:], " "))
if err != nil {
r.server.sendServerMessage(logger.Error(r.server.user, commandParseWarning, err))
return
}
re = deserializedRegex
}
if argc < 3 {
r.server.sendServerWarnMessage(logger.Warn(r.server.user, commandParseWarning, args, argc))
return
}
r.readGlob(ctx, lContext, args[1], re, retries)
}
func (r *readCommand) readGlob(ctx context.Context, lContext lcontext.LContext, glob string, re regex.Regex, retries int) {
retryInterval := time.Second * 5
glob = filepath.Clean(glob)
for retryCount := 0; retryCount < retries; retryCount++ {
paths, err := filepath.Glob(glob)
if err != nil {
logger.Warn(r.server.user, glob, err)
time.Sleep(retryInterval)
continue
}
if numPaths := len(paths); numPaths == 0 {
logger.Error(r.server.user, "No such file(s) to read", glob)
r.server.sendServerWarnMessage(logger.Warn(r.server.user, "Unable to read file(s), check server logs"))
select {
case <-ctx.Done():
return
default:
}
time.Sleep(retryInterval)
continue
}
r.readFiles(ctx, lContext, paths, glob, re, retryInterval)
return
}
r.server.sendServerWarnMessage(logger.Warn(r.server.user, "Giving up to read file(s)"))
return
}
func (r *readCommand) readFiles(ctx context.Context, lContext lcontext.LContext, paths []string, glob string, re regex.Regex, retryInterval time.Duration) {
var wg sync.WaitGroup
wg.Add(len(paths))
for _, path := range paths {
go r.readFileIfPermissions(ctx, lContext, &wg, path, glob, re)
}
wg.Wait()
}
func (r *readCommand) readFileIfPermissions(ctx context.Context, lContext lcontext.LContext, wg *sync.WaitGroup, path, glob string, re regex.Regex) {
defer wg.Done()
globID := r.makeGlobID(path, glob)
if !r.server.user.HasFilePermission(path, "readfiles") {
logger.Error(r.server.user, "No permission to read file", path, globID)
r.server.sendServerWarnMessage(logger.Warn(r.server.user, "Unable to read file(s), check server logs"))
return
}
r.readFile(ctx, lContext, path, globID, re)
}
func (r *readCommand) readFile(ctx context.Context, lContext lcontext.LContext, path, globID string, re regex.Regex) {
logger.Info(r.server.user, "Start reading file", path, globID)
var reader fs.FileReader
switch r.mode {
case omode.TailClient:
reader = fs.NewTailFile(path, globID, r.server.serverMessages, r.server.tailLimiter)
case omode.GrepClient, omode.CatClient:
reader = fs.NewCatFile(path, globID, r.server.serverMessages, r.server.catLimiter)
default:
reader = fs.NewTailFile(path, globID, r.server.serverMessages, r.server.tailLimiter)
}
lines := r.server.lines
// Plug in mappreduce engine
if r.server.aggregate != nil {
lines = r.server.aggregate.Lines
}
for {
if err := reader.Start(ctx, lContext, lines, re); err != nil {
logger.Error(r.server.user, path, globID, err)
}
select {
case <-ctx.Done():
return
default:
if !reader.Retry() {
return
}
}
time.Sleep(time.Second * 2)
logger.Info(path, globID, "Reading file again")
}
}
func (r *readCommand) makeGlobID(path, glob string) string {
var idParts []string
pathParts := strings.Split(path, "/")
for i, globPart := range strings.Split(glob, "/") {
if strings.Contains(globPart, "*") {
idParts = append(idParts, pathParts[i])
}
}
if len(idParts) > 0 {
return strings.Join(idParts, "/")
}
if len(pathParts) > 0 {
return pathParts[len(pathParts)-1]
}
r.server.sendServerWarnMessage(logger.Warn("Empty file path given?", path, glob))
return ""
}
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