/
memlog.go
157 lines (143 loc) · 3.55 KB
/
memlog.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
package logging
import (
"log"
"strings"
"sync"
"time"
)
// MemoryLoggerFlags is the assumed layout for the log
const MemoryLoggerFlags = log.Lshortfile
// LogEntry is a linked list entry that holds log entries
type LogEntry struct {
Time time.Time
Location string
Message string
Next *LogEntry
Level uint
}
// NewLogEntry creates a new log entry
func NewLogEntry(input string, level uint) *LogEntry {
fields := strings.Split(input, ":")
if len(fields) > 2 {
file := fields[0]
line := fields[1]
message := strings.Join(fields[2:], ":")
return &LogEntry{Time: time.Now(), Message: message, Location: file + ":" + line, Next: nil, Level: level}
}
return &LogEntry{Time: time.Now(), Message: input, Location: "-", Next: nil, Level: level}
}
// MemoryLogger is a type that logs to memory. The logs are stored in a linked
// list.
type MemoryLogger struct {
FirstEntry *LogEntry
LastEntry *LogEntry
numEntries int
maxEntries int
level uint
mutex sync.Mutex
}
// NewMemoryLogger creates a new memory logger
func NewMemoryLogger(maxEntries int, l uint) *MemoryLogger {
if maxEntries < 1 {
maxEntries = 1
}
return &MemoryLogger{
mutex: sync.Mutex{},
maxEntries: maxEntries,
FirstEntry: nil,
LastEntry: nil,
level: l,
numEntries: 0}
}
// NewMemoryLoggers is a convenience function to create logs for all levels
func NewMemoryLoggers(maxEntries int) []*MemoryLogger {
return []*MemoryLogger{
NewMemoryLogger(maxEntries, DebugLevel),
NewMemoryLogger(maxEntries, InfoLevel),
NewMemoryLogger(maxEntries, WarningLevel),
NewMemoryLogger(maxEntries, ErrorLevel),
}
}
func (m *MemoryLogger) addEntry(entry *LogEntry) {
m.mutex.Lock()
defer m.mutex.Unlock()
m.numEntries++
e := m.FirstEntry
if e == nil {
m.FirstEntry = entry
m.LastEntry = entry
return
}
m.LastEntry.Next = entry
m.LastEntry = m.LastEntry.Next
// Remove the first entry if we exceed max number of entries
if m.numEntries > m.maxEntries {
remove := m.FirstEntry
m.FirstEntry = m.FirstEntry.Next
remove.Next = nil
return
}
}
// Write is a stub. This is the io.Writer implementation
func (m *MemoryLogger) Write(p []byte) (n int, err error) {
m.addEntry(NewLogEntry(string(p), m.level))
return len(p), nil
}
// Entries returns the entries
func (m *MemoryLogger) Entries() []LogEntry {
m.mutex.Lock()
defer m.mutex.Unlock()
var ret []LogEntry
e := m.FirstEntry
for e != nil {
ret = append(ret, *e)
e = e.Next
}
return ret
}
// Merge merges this and a number of other logs
func (m *MemoryLogger) Merge(other ...*MemoryLogger) []LogEntry {
ret := make([]LogEntry, 0)
elems := make([]*LogEntry, len(other)+1)
elems[0] = m.FirstEntry
m.mutex.Lock()
for i, o := range other {
o.mutex.Lock()
elems[i+1] = o.FirstEntry
}
for len(elems) > 0 {
// Remove all elems that are nil
newElems := make([]*LogEntry, 0)
for _, v := range elems {
if v != nil {
newElems = append(newElems, v)
}
}
elems = newElems
// Find the next lowest element and move forward
min := time.Now()
smallest := -1
for i := range elems {
if elems[i].Time.Before(min) {
min = elems[i].Time
smallest = i
}
}
if smallest >= 0 {
ret = append(ret, *elems[smallest])
elems[smallest] = elems[smallest].Next
}
}
m.mutex.Unlock()
for _, o := range other {
o.mutex.Unlock()
}
return ret
}
// NumEntries returns the number of entries in the log in total. This
// is increased for every time something is logged to the logger.
func (m *MemoryLogger) NumEntries() int {
m.mutex.Lock()
defer m.mutex.Unlock()
return m.numEntries
}