discovery/file/file.go
func (d *Discovery) refresh(ctx context.Context, ch chan<- []*targetgroup.Group) {
	t0 := time.Now()
	defer func() {
		fileSDScanDuration.Observe(time.Since(t0).Seconds())
	}()
	ref := map[string]int{}
	for _, p := range d.listFiles() {
		tgroups, err := d.readFile(p)
		if err != nil {
			fileSDReadErrorsCount.Inc()

			level.Error(d.logger).Log("msg", "Error reading file", "path", p, "err", err)
			// Prevent deletion down below.
			ref[p] = d.lastRefresh[p]
			continue
		}
		select {
		case ch <- tgroups:
		case <-ctx.Done():
			return
		}

		ref[p] = len(tgroups)
	}
	// Send empty updates for sources that disappeared.
	for f, n := range d.lastRefresh {
		m, ok := ref[f]
		if !ok || n > m {
			level.Debug(d.logger).Log("msg", "file_sd refresh found file that should be removed", "file", f)
			d.deleteTimestamp(f)
			for i := m; i < n; i++ {
				select {
				case ch <- []*targetgroup.Group{{Source: fileSource(f, i)}}:
				case <-ctx.Done():
					return
				}
			}
		}
	}
	d.lastRefresh = ref

	d.watchFiles()
}
func (d *Discovery) refresh(ctx context.Context, ch chan<- []*targetgroup.Group) {
	t0 := time.Now()
	defer func() {
		fileSDScanDuration.Observe(time.Since(t0).Seconds())
	}()
	ref := map[string]int{}
	for _, p := range d.listFiles() {
		tgroups, err := d.readFile(p)
		if err != nil {
			fileSDReadErrorsCount.Inc()

			level.Error(d.logger).Log("msg", "Error reading file", "path", p, "err", err)
			// Prevent deletion down below.
			ref[p] = d.lastRefresh[p]
			continue
		}
		select {
		case ch <- tgroups:
		case <-ctx.Done():
			return
		}

		ref[p] = len(tgroups)
	}
	// Send empty updates for sources that disappeared.
	for f, n := range d.lastRefresh {
		m, ok := ref[f]
		if !ok || n > m {
			level.Debug(d.logger).Log("msg", "file_sd refresh found file that should be removed", "file", f)
			d.deleteTimestamp(f)
			for i := m; i < n; i++ {
				select {
				case ch <- []*targetgroup.Group{{Source: fileSource(f, i)}}:
				case <-ctx.Done():
					return
				}
			}
		}
	}
	d.lastRefresh = ref

	d.watchFiles()
}
func ( d * Discovery ) refresh ( ctx context . Context , ch chan <- [ ] * targetgroup . Group ) { t0 := time . Now ( ) defer func ( ) { fileSDScanDuration . Observe ( time . Since ( t0 ) . Seconds ( ) ) } ( ) ref := map [ string ] int { } for _ , p := range d . listFiles ( ) { tgroups , err := d . readFile ( p ) if err != nil { fileSDReadErrorsCount . Inc ( ) level . Error ( d . logger ) . Log ( " " , " " , " " , p , " " , err ) // Prevent deletion down below. ref [ p ] = d . lastRefresh [ p ] continue } select { case ch <- tgroups : case <- ctx . Done ( ) : return } ref [ p ] = len ( tgroups ) } // Send empty updates for sources that disappeared. for f , n := range d . lastRefresh { m , ok := ref [ f ] if ! ok || n > m { level . Debug ( d . logger ) . Log ( " " , " " , " " , f ) d . deleteTimestamp ( f ) for i := m ; i < n ; i ++ { select { case ch <- [ ] * targetgroup . Group { { Source : fileSource ( f , i ) } } : case <- ctx . Done ( ) : return } } } } d . lastRefresh = ref d . watchFiles ( ) }
// refresh reads all files matching the discovery's patterns and sends the respective
// updated target groups through the channel.
refresh reads all files matching the discovery s patterns and sends the respective updated target groups through the channel .