1/*
2Copyright (c) 2015 VMware, Inc. All Rights Reserved.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8    http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17package object
18
19import (
20	"context"
21	"fmt"
22	"io"
23	"math"
24)
25
26// DiagnosticLog wraps DiagnosticManager.BrowseLog
27type DiagnosticLog struct {
28	m DiagnosticManager
29
30	Key  string
31	Host *HostSystem
32
33	Start int32
34}
35
36// Seek to log position starting at the last nlines of the log
37func (l *DiagnosticLog) Seek(ctx context.Context, nlines int32) error {
38	h, err := l.m.BrowseLog(ctx, l.Host, l.Key, math.MaxInt32, 0)
39	if err != nil {
40		return err
41	}
42
43	l.Start = h.LineEnd - nlines
44
45	return nil
46}
47
48// Copy log starting from l.Start to the given io.Writer
49// Returns on error or when end of log is reached.
50func (l *DiagnosticLog) Copy(ctx context.Context, w io.Writer) (int, error) {
51	const max = 500 // VC max == 500, ESX max == 1000
52	written := 0
53
54	for {
55		h, err := l.m.BrowseLog(ctx, l.Host, l.Key, l.Start, max)
56		if err != nil {
57			return 0, err
58		}
59
60		for _, line := range h.LineText {
61			n, err := fmt.Fprintln(w, line)
62			written += n
63			if err != nil {
64				return written, err
65			}
66		}
67
68		l.Start += int32(len(h.LineText))
69
70		if l.Start >= h.LineEnd {
71			break
72		}
73	}
74
75	return written, nil
76}
77