import (
	"io"
	"os"
)

const (
	// blockSize is the block size used in tail.
	blockSize = 1024
)

// ReadAtMost reads at most max bytes from the end of the file identified by path or
// returns an error. It returns true if the file was longer than max. It will
// allocate up to max bytes.
func ReadAtMost(path string, max int64) ([]byte, bool, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, false, err
	}

			max:           4613,
			longerThanMax: false,
			expected:      string(testBytes),
		},
	}

	for _, test := range testCases {
		readAtMostBytes, longerThanMax, err := ReadAtMost(file.Name(), test.max)
		if err != nil {
			t.Fatalf("Unexpected failure %v", err)
		}
		if test.longerThanMax != longerThanMax {

	headers := req.Header
	res, err := client.Do(req)
	if err != nil {
		// Convert errors into failures to catch timeouts.
		return probe.Failure, err.Error(), nil
	}
	defer res.Body.Close()
	b, err := utilio.ReadAtMost(res.Body, maxRespBodyLength)
	if err != nil {
		if err == utilio.ErrLimitReached {
			klog.V(4).Infof("Non fatal body truncation for %s, Response: %v", url.String(), *res)
		} else {
			return probe.Failure, "", err

	if err != nil {
		return err
	}
	req.Header = s.header
	resp, err := s.client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	data, err := utilio.ReadAtMost(resp.Body, maxConfigLength)
	if err != nil {
		return err
	}
	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("%v: %v", s.url, resp.Status)
	}
	if len(data) == 0 {

				return
			}
			s.fileKeyMapping[filename] = objKey
		}
	}()

	file, err := os.Open(filename)
	if err != nil {
		return pod, err
	}
	defer file.Close()

	data, err := utilio.ReadAtMost(file, maxConfigLength)
	if err != nil {
		return pod, err
	}

	defaultFn := func(pod *api.Pod) error {
		return s.applyDefaults(pod, filename)
	}

// it into nameservers, searches and options, possibly returning an error.
func parseResolvConf(reader io.Reader) (nameservers []string, searches []string, options []string, err error) {
	file, err := utilio.ReadAtMost(reader, maxResolvConfLength)
	if err != nil {
		return nil, nil, nil, err
	}

	// Lines of the form "nameserver 1.2.3.4" accumulate.
	nameservers = []string{}

		w.WriteHeader(http.StatusOK)
		return
	}
	// We only write the status code to the response.
	w.WriteHeader(response.StatusCode)
	// Return the body from probe as well
	b, _ := k8sUtilIo.ReadAtMost(response.Body, maxRespBodyLength)
	_, _ = w.Write(b)
}

func (s *Server) handleAppProbeTCPSocket(w http.ResponseWriter, prober *Prober) {
	timeout := time.Duration(prober.TimeoutSeconds) * time.Second

	for _, mount := range status.Mounts {
		if mount.ContainerPath != terminationMessagePath {
			continue
		}
		path := mount.HostPath
		data, _, err := tail.ReadAtMost(path, kubecontainer.MaxContainerTerminationMessageLength)
		if err != nil {
			if os.IsNotExist(err) {
				return "", fallbackToLogs
			}