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* simv2: wip * simulation: exec adapter start/stop * simulation: add node status to exec adapter * simulation: initial simulation code * simulation: exec adapter, configure path to executable * simulation: initial docker adapter * simulation: wip kubernetes adapter * simulation: kubernetes adapter proxy * simulation: implement GetAll/StartAll/StopAll * simulation: kuberentes adapter - set env vars and resource limits * simulation: discovery test * simulation: remove port definitions within docker adapter * simulation: simplify wait for healthy loop * simulation: get nat ip addr from interface * simulation: pull docker images automatically * simulation: NodeStatus -> NodeInfo * simulation: move discovery test to example dir * simulation: example snapshot usage * simulation: add goclient specific simulation * simulation: add peer connections to snapshot * simulation: close rpc client * simulation: don't export kubernetes proxy server * simulation: merge simulation code * simulation: don't export nodemap * simulation: rename SimulationSnapshot -> Snapshot * simulation: linting fixes * simulation: add k8s available helper func * simulation: vendor * simulation: fix 'no non-test Go files' when building * simulation: remove errors from interface methods where non were returned * simulation: run getHealthInfo check in parallel
102 lines
3.9 KiB
Markdown
102 lines
3.9 KiB
Markdown
# go-digest
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[](https://godoc.org/github.com/opencontainers/go-digest) [](https://goreportcard.com/report/github.com/opencontainers/go-digest) [](https://travis-ci.org/opencontainers/go-digest)
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Common digest package used across the container ecosystem.
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Please see the [godoc](https://godoc.org/github.com/opencontainers/go-digest) for more information.
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# What is a digest?
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A digest is just a hash.
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The most common use case for a digest is to create a content
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identifier for use in [Content Addressable Storage](https://en.wikipedia.org/wiki/Content-addressable_storage)
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systems:
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```go
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id := digest.FromBytes([]byte("my content"))
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```
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In the example above, the id can be used to uniquely identify
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the byte slice "my content". This allows two disparate applications
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to agree on a verifiable identifier without having to trust one
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another.
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An identifying digest can be verified, as follows:
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```go
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if id != digest.FromBytes([]byte("my content")) {
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return errors.New("the content has changed!")
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}
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```
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A `Verifier` type can be used to handle cases where an `io.Reader`
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makes more sense:
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```go
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rd := getContent()
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verifier := id.Verifier()
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io.Copy(verifier, rd)
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if !verifier.Verified() {
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return errors.New("the content has changed!")
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}
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```
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Using [Merkle DAGs](https://en.wikipedia.org/wiki/Merkle_tree), this
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can power a rich, safe, content distribution system.
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# Usage
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While the [godoc](https://godoc.org/github.com/opencontainers/go-digest) is
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considered the best resource, a few important items need to be called
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out when using this package.
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1. Make sure to import the hash implementations into your application
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or the package will panic. You should have something like the
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following in the main (or other entrypoint) of your application:
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```go
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import (
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_ "crypto/sha256"
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_ "crypto/sha512"
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)
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```
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This may seem inconvenient but it allows you replace the hash
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implementations with others, such as https://github.com/stevvooe/resumable.
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2. Even though `digest.Digest` may be assemable as a string, _always_
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verify your input with `digest.Parse` or use `Digest.Validate`
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when accepting untrusted input. While there are measures to
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avoid common problems, this will ensure you have valid digests
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in the rest of your application.
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# Stability
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The Go API, at this stage, is considered stable, unless otherwise noted.
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As always, before using a package export, read the [godoc](https://godoc.org/github.com/opencontainers/go-digest).
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# Contributing
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This package is considered fairly complete. It has been in production
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in thousands (millions?) of deployments and is fairly battle-hardened.
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New additions will be met with skepticism. If you think there is a
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missing feature, please file a bug clearly describing the problem and
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the alternatives you tried before submitting a PR.
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## Code of Conduct
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Participation in the OpenContainers community is governed by [OpenContainer's Code of Conduct][code-of-conduct].
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## Security
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If you find an issue, please follow the [security][security] protocol to report it.
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# Copyright and license
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Copyright © 2016 Docker, Inc. All rights reserved, except as follows. Code is released under the [Apache 2.0 license](LICENSE). This `README.md` file and the [`CONTRIBUTING.md`](CONTRIBUTING.md) file are licensed under the Creative Commons Attribution 4.0 International License under the terms and conditions set forth in the file [`LICENSE.docs`](LICENSE.docs). You may obtain a duplicate copy of the same license, titled CC BY-SA 4.0, at http://creativecommons.org/licenses/by-sa/4.0/.
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[security]: https://github.com/opencontainers/org/blob/master/security
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[code-of-conduct]: https://github.com/opencontainers/org/blob/master/CODE_OF_CONDUCT.md
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