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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
package sql
import (
"database/sql"
"sync"
"time"
"github.com/jmoiron/sqlx"
_ "github.com/mattn/go-sqlite3" // SQLite database driver
)
const schema = `
CREATE TABLE IF NOT EXISTS rr_question (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
CONSTRAINT name_unique UNIQUE (name)
);
CREATE TABLE IF NOT EXISTS rr_answer (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
CONSTRAINT name_unique UNIQUE(name)
);
CREATE TABLE IF NOT EXISTS rr_type (
id INTEGER PRIMARY KEY,
type INTEGER NOT NULL,
CONSTRAINT type_unique UNIQUE(type)
);
CREATE TABLE IF NOT EXISTS remote_addr (
id INTEGER PRIMARY KEY,
addr BLOB NOT NULL,
CONSTRAINT addr_unique UNIQUE(addr)
);
CREATE TABLE IF NOT EXISTS log (
id INTEGER PRIMARY KEY,
time INTEGER NOT NULL,
remote_addr_id INTEGER NOT NULL,
rr_type_id INTEGER NOT NULL,
rr_question_id INTEGER NOT NULL,
FOREIGN KEY (remote_addr_id) REFERENCES remote_addr(id),
FOREIGN KEY (rr_question_id) REFERENCES rr_question(id),
FOREIGN KEY (rr_type_id) REFERENCES rr_type(id)
);
CREATE TABLE IF NOT EXISTS log_rr_answer (
id INTEGER PRIMARY KEY,
log_id INTEGER NOT NULL,
rr_answer_id INTEGER NOT NULL,
FOREIGN KEY (log_id) REFERENCES log(id),
FOREIGN KEY (rr_answer_id) REFERENCES rr_answer(id)
);
`
// Client implements a client for a SQLite database.
type Client struct {
db *sqlx.DB
mu sync.RWMutex
}
// LogEntry represents an entry in the log.
type LogEntry struct {
ID int64 `db:"id"`
Time int64 `db:"time"`
RemoteAddr []byte `db:"remote_addr"`
Qtype uint16 `db:"type"`
Question string `db:"question"`
Answer string `db:"answer"`
}
// New creates a new database client for given filename.
func New(filename string) (*Client, error) {
db, err := sqlx.Connect("sqlite3", filename)
if err != nil {
return nil, err
}
// Ensure foreign keys are enabled (defaults to off)
if _, err := db.Exec("PRAGMA foreign_keys = ON"); err != nil {
return nil, err
}
if _, err := db.Exec(schema); err != nil {
return nil, err
}
return &Client{db: db}, nil
}
// ReadLog reads the n most recent entries from the log.
func (c *Client) ReadLog(n int) ([]LogEntry, error) {
c.mu.RLock()
defer c.mu.RUnlock()
query := `
SELECT log.id AS id,
time,
remote_addr.addr AS remote_addr,
type,
rr_question.name AS question,
rr_answer.name AS answer
FROM log
INNER JOIN remote_addr ON remote_addr.id = log.remote_addr_id
INNER JOIN rr_question ON rr_question.id = rr_question_id
INNER JOIN rr_type ON rr_type.id = rr_type_id
INNER JOIN log_rr_answer ON log_rr_answer.log_id = log.id
INNER JOIN rr_answer ON rr_answer.id = log_rr_answer.rr_answer_id
WHERE log.id IN (SELECT id FROM log ORDER BY time DESC LIMIT $1)
ORDER BY time DESC, rr_answer.id DESC
`
var entries []LogEntry
err := c.db.Select(&entries, query, n)
return entries, err
}
func getOrInsert(tx *sqlx.Tx, table, column string, value interface{}) (int64, error) {
var id int64
err := tx.Get(&id, "SELECT id FROM "+table+" WHERE "+column+" = ?", value)
if err == sql.ErrNoRows {
res, err := tx.Exec("INSERT INTO "+table+" ("+column+") VALUES (?)", value)
if err != nil {
return 0, err
}
return res.LastInsertId()
}
return id, err
}
// WriteLog writes a new entry to the log.
func (c *Client) WriteLog(time time.Time, remoteAddr []byte, qtype uint16, question string, answers ...string) error {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return err
}
defer tx.Rollback()
typeID, err := getOrInsert(tx, "rr_type", "type", qtype)
if err != nil {
return err
}
questionID, err := getOrInsert(tx, "rr_question", "name", question)
if err != nil {
return err
}
remoteAddrID, err := getOrInsert(tx, "remote_addr", "addr", remoteAddr)
if err != nil {
return err
}
answerIDs := make([]int64, 0, len(answers))
for _, answer := range answers {
answerID, err := getOrInsert(tx, "rr_answer", "name", answer)
if err != nil {
return err
}
answerIDs = append(answerIDs, answerID)
}
res, err := tx.Exec("INSERT INTO log (time, remote_addr_id, rr_type_id, rr_question_id) VALUES ($1, $2, $3, $4)", time.Unix(), remoteAddrID, typeID, questionID)
if err != nil {
return err
}
logID, err := res.LastInsertId()
if err != nil {
return err
}
for _, answerID := range answerIDs {
if _, err := tx.Exec("INSERT INTO log_rr_answer (log_id, rr_answer_id) VALUES ($1, $2)", logID, answerID); err != nil {
return err
}
}
return tx.Commit()
}
// DeleteLogBefore deletes all log entries occurring before time t.
func (c *Client) DeleteLogBefore(t time.Time) (err error) {
c.mu.Lock()
defer c.mu.Unlock()
tx, err := c.db.Beginx()
if err != nil {
return nil
}
defer tx.Rollback()
if _, err := tx.Exec("DELETE FROM log_rr_answer WHERE log_id IN (SELECT id FROM log WHERE time < $1)", t.Unix()); err != nil {
return err
}
if _, err := tx.Exec("DELETE FROM log WHERE id NOT IN (SELECT log_id FROM log_rr_answer)"); err != nil {
return err
}
if _, err := tx.Exec("DELETE FROM rr_type WHERE id NOT IN (SELECT rr_type_id FROM log)"); err != nil {
return err
}
if _, err := tx.Exec("DELETE FROM rr_question WHERE id NOT IN (SELECT rr_question_id FROM log)"); err != nil {
return err
}
if _, err := tx.Exec("DELETE FROM rr_answer WHERE id NOT IN (SELECT rr_answer_id FROM log_rr_answer)"); err != nil {
return err
}
if _, err := tx.Exec("DELETE FROM remote_addr WHERE id NOT IN (SELECT remote_addr_id FROM log)"); err != nil {
return err
}
return tx.Commit()
}
|
