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package handlers
import (
"context"
"os"
"path/filepath"
"strings"
"sync"
"time"
"github.com/mimecast/dtail/internal/io/dlog"
"github.com/mimecast/dtail/internal/io/fs"
"github.com/mimecast/dtail/internal/io/line"
"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, ltx 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.sendln(r.server.serverMessages, dlog.Server.Error(r.server.user,
"Unable to parse command", err))
return
}
re = deserializedRegex
}
if argc < 3 {
r.server.sendln(r.server.serverMessages, dlog.Server.Warn(r.server.user,
"Unable to parse command", args, argc))
return
}
// In serverless mode, can also read data from pipe
// e.g.: grep foo bar.log | dmap 'from STATS select ...'
if r.isInputFromPipe() {
dlog.Server.Debug("Reading data from stdin pipe")
// Empty file path and globID "-" represents reading from the stdin pipe.
r.read(ctx, ltx, "", "-", re)
return
}
dlog.Server.Debug("Reading data from file(s)")
r.readGlob(ctx, ltx, args[1], re, retries)
}
func (r *readCommand) readGlob(ctx context.Context, ltx 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 {
dlog.Server.Warn(r.server.user, glob, err)
time.Sleep(retryInterval)
continue
}
if numPaths := len(paths); numPaths == 0 {
dlog.Server.Error(r.server.user, "No such file(s) to read", glob)
r.server.sendln(r.server.serverMessages, dlog.Server.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, ltx, paths, glob, re, retryInterval)
return
}
r.server.sendln(r.server.serverMessages, dlog.Server.Warn(r.server.user,
"Giving up to read file(s)"))
return
}
func (r *readCommand) readFiles(ctx context.Context, ltx 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, ltx, &wg, path, glob, re)
}
wg.Wait()
}
func (r *readCommand) readFileIfPermissions(ctx context.Context, ltx 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") {
dlog.Server.Error(r.server.user, "No permission to read file", path, globID)
r.server.sendln(r.server.serverMessages, dlog.Server.Warn(r.server.user,
"Unable to read file(s), check server logs"))
return
}
r.read(ctx, ltx, path, globID, re)
}
func (r *readCommand) read(ctx context.Context, ltx lcontext.LContext,
path, globID string, re regex.Regex) {
dlog.Server.Info(r.server.user, "Start reading", path, globID)
var reader fs.FileReader
var limiter chan struct{}
switch r.mode {
case omode.GrepClient, omode.CatClient:
reader = fs.NewCatFile(path, globID, r.server.serverMessages)
limiter = r.server.catLimiter
case omode.TailClient:
fallthrough
default:
reader = fs.NewTailFile(path, globID, r.server.serverMessages)
limiter = r.server.tailLimiter
}
defer func() {
select {
case <-limiter:
default:
}
}()
select {
case limiter <- struct{}{}:
case <-ctx.Done():
return
default:
dlog.Server.Info("Server limit hit, queueing file", len(limiter), path)
select {
case limiter <- struct{}{}:
dlog.Server.Info("Server limit OK now, processing file", len(limiter), path)
case <-ctx.Done():
return
}
}
lines := r.server.lines
aggregate := r.server.aggregate
for {
if aggregate != nil {
lines = make(chan *line.Line, 100)
aggregate.NextLinesCh <- lines
}
if err := reader.Start(ctx, ltx, lines, re); err != nil {
dlog.Server.Error(r.server.user, path, globID, err)
}
if aggregate != nil {
// Also makes aggregate to Flush
close(lines)
}
select {
case <-ctx.Done():
return
default:
if !reader.Retry() {
return
}
}
time.Sleep(time.Second * 2)
dlog.Server.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.sendln(r.server.serverMessages,
dlog.Server.Warn("Empty file path given?", path, glob))
return ""
}
func (r *readCommand) isInputFromPipe() bool {
if !r.server.serverless {
// Can read from pipe only in serverless mode.
return false
}
fileInfo, _ := os.Stdin.Stat()
return fileInfo.Mode()&os.ModeCharDevice == 0
}
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