4ba4f3a1d5
The namespaced snapshotter wraps an existing snapshotter and enforces namespace. Signed-off-by: Derek McGowan <derek@mcgstyle.net>
41 lines
1.2 KiB
Go
41 lines
1.2 KiB
Go
package metadata
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import (
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"context"
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"github.com/boltdb/bolt"
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"github.com/pkg/errors"
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)
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type transactionKey struct{}
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// WithTransactionContext returns a new context holding the provided
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// bolt transaction. Functions which require a bolt transaction will
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// first check to see if a transaction is already created on the
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// context before creating their own.
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func WithTransactionContext(ctx context.Context, tx *bolt.Tx) context.Context {
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return context.WithValue(ctx, transactionKey{}, tx)
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}
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// view gets a bolt db transaction either from the context
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// or starts a new one with the provided bolt database.
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func view(ctx context.Context, db *bolt.DB, fn func(*bolt.Tx) error) error {
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tx, ok := ctx.Value(transactionKey{}).(*bolt.Tx)
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if !ok {
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return db.View(fn)
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}
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return fn(tx)
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}
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// update gets a writable bolt db transaction either from the context
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// or starts a new one with the provided bolt database.
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func update(ctx context.Context, db *bolt.DB, fn func(*bolt.Tx) error) error {
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tx, ok := ctx.Value(transactionKey{}).(*bolt.Tx)
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if !ok {
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return db.Update(fn)
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} else if !tx.Writable() {
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return errors.Wrap(bolt.ErrTxNotWritable, "unable to use transaction from context")
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}
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return fn(tx)
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}
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