mirror of
https://github.com/tiennm99/keepalive.git
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tiennm99
0af652953f
- Each connect attempt, including initialization, times out after 1 minute, and PostgreSQL DSNs without connect_timeout get connect_timeout=30, since lib/pq honours the context only while dialing. - A service increments right after connecting, so a restart writes even when the interval outlasts the process. - A config path that is a directory (Docker's stand-in for a missing bind-mount source) fails with a clear message. - Generated service names take the first free suffix, and suffixed names are reserved so an explicit name cannot silently collide with them. - counter_key inside a service's config map is rejected instead of being overwritten. - Unknown keys in the config file log a warning without blocking start. - A .dockerignore keeps local configs and .env out of the build context.
102 lines
2.2 KiB
Go
102 lines
2.2 KiB
Go
package adapter
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import (
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"context"
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"database/sql"
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"strings"
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_ "github.com/lib/pq"
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)
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func init() {
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Registry["postgresql"] = func(cfg Config) (Adapter, error) {
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url, err := cfg.Required("url")
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if err != nil {
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return nil, err
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}
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return &postgresAdapter{
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url: withDefaultConnectTimeout(url),
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key: cfg.Optional("counter_key", "counter"),
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}, nil
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}
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Registry["postgres"] = Registry["postgresql"]
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}
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type postgresAdapter struct {
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db *sql.DB
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url string
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key string
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}
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func (a *postgresAdapter) Connect(ctx context.Context) error {
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db, err := sql.Open("postgres", a.url)
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if err != nil {
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return err
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}
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a.db = db
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if err := a.db.PingContext(ctx); err != nil {
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a.db.Close()
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return err
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}
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if err := a.ensureInitialized(ctx); err != nil {
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a.db.Close()
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return err
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}
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return nil
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}
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func (a *postgresAdapter) ensureInitialized(ctx context.Context) error {
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if _, err := a.db.ExecContext(ctx, `
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CREATE TABLE IF NOT EXISTS keepalive (
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key TEXT PRIMARY KEY,
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value BIGINT NOT NULL DEFAULT 0
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)`); err != nil {
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return err
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}
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_, err := a.db.ExecContext(ctx,
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`INSERT INTO keepalive (key, value) VALUES ($1, 0) ON CONFLICT (key) DO NOTHING`,
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a.key,
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)
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return err
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}
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func (a *postgresAdapter) Increment(ctx context.Context) (int64, error) {
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tx, err := a.db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
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if err != nil {
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return 0, err
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}
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var value int64
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if err := tx.QueryRowContext(ctx,
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`UPDATE keepalive SET value = value + 1 WHERE key = $1 RETURNING value`,
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a.key,
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).Scan(&value); err != nil {
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tx.Rollback()
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return 0, err
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}
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return value, tx.Commit()
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}
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func (a *postgresAdapter) Close(_ context.Context) error {
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if a.db == nil {
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return nil
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}
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return a.db.Close()
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}
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// withDefaultConnectTimeout adds connect_timeout when the DSN has none:
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// lib/pq honours the context only while dialing, so a server that accepts the
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// connection but never answers the startup handshake would hang forever.
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func withDefaultConnectTimeout(dsn string) string {
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if strings.Contains(dsn, "connect_timeout") {
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return dsn
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}
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switch {
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case !strings.Contains(dsn, "://"):
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return dsn + " connect_timeout=30"
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case strings.Contains(dsn, "?"):
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return dsn + "&connect_timeout=30"
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default:
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return dsn + "?connect_timeout=30"
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}
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}
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