forked from
tangled.org/core
this repo has no description
add migration handler
+55
+55
appview/db/db.go
+55
appview/db/db.go
···
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import (
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"context"
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"database/sql"
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"log"
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_ "github.com/mattn/go-sqlite3"
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)
···
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unique(starred_by_did, repo_at)
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);
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create table if not exists migrations (
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id integer primary key autoincrement,
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name text unique
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)
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`)
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if err != nil {
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return nil, err
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}
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// run migrations
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runMigration(db, "add-description-to-repos", func(tx *sql.Tx) error {
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tx.Exec(`
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alter table repos add column description text check (length(description) <= 200);
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`)
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return nil
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})
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return &DB{db}, nil
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}
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type migrationFn = func(*sql.Tx) error
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func runMigration(d *sql.DB, name string, migrationFn migrationFn) error {
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tx, err := d.Begin()
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if err != nil {
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return err
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}
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defer tx.Rollback()
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var exists bool
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err = tx.QueryRow("select exists (select 1 from migrations where name = ?)", name).Scan(&exists)
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if err != nil {
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return err
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}
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if !exists {
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// run migration
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err = migrationFn(tx)
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if err != nil {
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log.Printf("Failed to run migration %s: %v", name, err)
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return err
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}
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// mark migration as complete
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_, err = tx.Exec("insert into migrations (name) values (?)", name)
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if err != nil {
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log.Printf("Failed to mark migration %s as complete: %v", name, err)
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return err
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}
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// commit the transaction
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if err := tx.Commit(); err != nil {
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return err
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}
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} else {
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log.Printf("skipped migration %s, already applied", name)
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}
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return nil
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}