8d892a651b
Updates metadata plugin to require content and snapshotter plugins be loaded and initializes with those plugins, keeping the metadata database structure static after initialization. Service plugins now only require metadata plugin access snapshotter or content stores through metadata, which was already required behavior of the services. Signed-off-by: Derek McGowan <derek@mcgstyle.net>
46 lines
1.3 KiB
Go
46 lines
1.3 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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type transactor interface {
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View(fn func(*bolt.Tx) error) error
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Update(fn func(*bolt.Tx) error) error
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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 transactor, 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 transactor, 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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