Files
lambdaiot-core/internal/storage/sqlite.go

87 lines
1.9 KiB
Go

package storage
import (
"database/sql"
"time"
_ "github.com/mattn/go-sqlite3"
)
// DB wraps sql.DB
type DB struct {
conn *sql.DB
}
// Default is the package-level DB used by handlers
var Default *DB
// Init opens the sqlite database at path and ensures the table exists
func Init(path string) (*DB, error) {
conn, err := sql.Open("sqlite3", path)
if err != nil {
return nil, err
}
// set reasonable pragmas
if _, err := conn.Exec("PRAGMA journal_mode=WAL;"); err != nil {
// ignore
}
schema := `CREATE TABLE IF NOT EXISTS messages (
message TEXT NOT NULL,
timestamp TEXT NOT NULL
);`
if _, err := conn.Exec(schema); err != nil {
conn.Close()
return nil, err
}
return &DB{conn: conn}, nil
}
// SetDefault sets the package default DB
func SetDefault(d *DB) {
Default = d
}
// Close closes the underlying connection
func (d *DB) Close() error {
if d == nil || d.conn == nil {
return nil
}
return d.conn.Close()
}
// InsertMessage inserts a message with timestamp into the DB
func (d *DB) InsertMessage(msg string, ts time.Time) error {
if d == nil || d.conn == nil {
return nil
}
_, err := d.conn.Exec("INSERT INTO messages(message, timestamp) VALUES(?, ?)", msg, ts.Format(time.RFC3339))
return err
}
// Message is the returned message shape
type Message struct {
Message string `json:"message"`
Timestamp string `json:"timestamp"`
}
// QueryMessages returns messages ordered by newest first
func (d *DB) QueryMessages(limit, offset int) ([]Message, error) {
if d == nil || d.conn == nil {
return nil, nil
}
rows, err := d.conn.Query("SELECT message, timestamp FROM messages ORDER BY rowid DESC LIMIT ? OFFSET ?", limit, offset)
if err != nil {
return nil, err
}
defer rows.Close()
res := []Message{}
for rows.Next() {
var m Message
if err := rows.Scan(&m.Message, &m.Timestamp); err != nil {
return nil, err
}
res = append(res, m)
}
return res, nil
}