bwilliams
65e5bc6b26
Each save that records a batch also deletes, in the same transaction, the batches older than database.change_batch_retention (30 days by default; 0 or less keeps them for ever), with their records of opportunities. A client still holding a deleted batch gets 410 Gone from ?changed_after= and reloads the whole list, as for any unknown batch.
58 lines
1.8 KiB
Go
58 lines
1.8 KiB
Go
package store
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import (
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"database/sql"
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"fmt"
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"time"
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)
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// Option configures Open.
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type Option func(*options)
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type options struct {
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autoMigrate bool
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changeBatchRetention time.Duration
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}
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// OpenDB opens the SQLite database at path with the store's connection
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// settings (foreign keys, WAL, busy timeout, immediate transactions). The
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// file is created on first use. Use it for anything that works on the store's
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// database directly, such as running migrations.
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func OpenDB(path string) (*sql.DB, error) {
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return sql.Open("sqlite3", dsn(path))
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}
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// WithAutoMigrate makes Open apply pending migrations instead of returning
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// ErrNeedsMigration. Intended for tests and throwaway databases; applications
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// should migrate explicitly with the migrate command.
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func WithAutoMigrate() Option {
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return func(opts *options) {
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opts.autoMigrate = true
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}
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}
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// WithChangeBatchRetention makes the store delete change batches older than
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// retention whenever it records a new one, so a client can catch up from a
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// batch for that long (see ListChangedOpportunities). Without it, or with 0
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// or less, batches are kept for ever.
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func WithChangeBatchRetention(retention time.Duration) Option {
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return func(opts *options) {
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opts.changeBatchRetention = retention
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}
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}
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// dsn builds the mattn/go-sqlite3 connection string.
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//
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// - _foreign_keys: SQLite ignores REFERENCES clauses unless this is on.
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// - _journal_mode=WAL: readers don't block the writer or each other.
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// - _busy_timeout: wait for a lock rather than failing immediately.
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// - _txlock=immediate: transactions take the write lock at BEGIN, so a
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// read-then-write transaction (as in SaveOpportunity) can't fail with
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// SQLITE_BUSY halfway through.
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func dsn(path string) string {
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return fmt.Sprintf(
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"file:%s?_foreign_keys=on&_journal_mode=WAL&_busy_timeout=5000&_txlock=immediate",
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path,
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)
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}
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