gnomon for Go

github.com/bitsinfra/gnomon/integrations/go: put a Go application, or each of its tests, on a branch of a PostgreSQL database with the gnomon extension. Built on pgx v5.

cfg, _ := pgxpool.ParseConfig(dsn)
cfg.AfterConnect = gnomon.AfterConnect("feature")            // every connection on the branch
pool, _ := pgxpool.NewWithConfig(ctx, cfg)

err := gnomon.WithBranch(ctx, pool, "feature", func(tx pgx.Tx) error {   // one transaction (poolers)
    _, err := tx.Exec(ctx, "update accounts set ...")
    return err
})
db, _ := gnomon.OpenDB(dsn, "feature")                       // database/sql

BranchOptions builds a libpq options value; ConnectionOptions asks the database (it knows scratch branches, mask profiles and schema versions). Use, CreateBranch, DropBranch, Merge; Code(err) is the stable [gnomon:<slug>] of an error, Explain(ctx, q, err) what gnomon.explain_error says about it.

Tests, each on its own scratch branch of one seeded database:

func TestSignup(t *testing.T) {
    conn := gnomontest.Branch(t, os.Getenv("GNOMON_TEST_DSN"))   // dropped when the test ends
    ...
}

go test ./... here runs against the repository's dev cluster (tools/devcluster.sh start), or the server GNOMON_TEST_SERVER names.