a4fadc596b
Now that we have most of the services required for use with containerd, it was found that common patterns were used throughout services. By defining a central `errdefs` package, we ensure that services will map errors to and from grpc consistently and cleanly. One can decorate an error with as much context as necessary, using `pkg/errors` and still have the error mapped correctly via grpc. We make a few sacrifices. At this point, the common errors we use across the repository all map directly to grpc error codes. While this seems positively crazy, it actually works out quite well. The error conditions that were specific weren't super necessary and the ones that were necessary now simply have better context information. We lose the ability to add new codes, but this constraint may not be a bad thing. Effectively, as long as one uses the errors defined in `errdefs`, the error class will be mapped correctly across the grpc boundary and everything will be good. If you don't use those definitions, the error maps to "unknown" and the error message is preserved. Signed-off-by: Stephen J Day <stephen.day@docker.com>
39 lines
609 B
Go
39 lines
609 B
Go
package content
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import (
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"sync"
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"github.com/containerd/containerd/errdefs"
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"github.com/pkg/errors"
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)
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// Handles locking references
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// TODO: use boltdb for lock status
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var (
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// locks lets us lock in process
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locks = map[string]struct{}{}
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locksMu sync.Mutex
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)
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func tryLock(ref string) error {
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locksMu.Lock()
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defer locksMu.Unlock()
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if _, ok := locks[ref]; ok {
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return errors.Wrapf(errdefs.ErrUnavailable, "ref %s locked", ref)
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}
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locks[ref] = struct{}{}
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return nil
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}
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func unlock(ref string) {
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locksMu.Lock()
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defer locksMu.Unlock()
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if _, ok := locks[ref]; ok {
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delete(locks, ref)
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}
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}
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