63 lines
2.3 KiB
Markdown
63 lines
2.3 KiB
Markdown
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Quinistry
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=========
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*A simple Docker registry quine.*
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## What?
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This is an example project for a from-scratch implementation of an HTTP server compatible with the [Docker Registry V2][]
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protocol.
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It serves a single image called `quinistry:latest` which is a Docker image that runs quinistry itself, therefore it is a
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sort of Docker registry [quine][].
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The official documentation does not contain enough information to actually implement this protocol (which I assume is
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intentional), but a bit of trial&error lead there anyways. I've added comments to parts of the code to clear up things
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that may be helpful to other developers in the future.
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## Example
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```
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# Run quinistry:
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vincent@urdhva ~/go/src/github.com/tazjin/quinistry (git)-[master] % ./quinistry
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2017/03/16 14:11:56 Starting quinistry
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# Pull the quinistry image from itself:
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vincent@urdhva ~ % docker pull localhost:8080/quinistry
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Using default tag: latest
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latest: Pulling from quinistry
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7bf1a8b18466: Already exists
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Digest: sha256:d5cd4490901ef04b4e28e4ccc03a1d25fe3461200cf4d7166aab86fcd495e22e
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Status: Downloaded newer image for localhost:8080/quinistry:latest
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# Quinistry will log:
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2017/03/16 14:14:03 Acknowleding V2 API: GET /v2/
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2017/03/16 14:14:03 Serving manifest: GET /v2/quinistry/manifests/latest
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2017/03/16 14:14:03 Serving config: GET /v2/quinistry/blobs/sha256:fbb165c48849de16017aa398aa9bb08fd1c00eaa7c150b6c2af37312913db279
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# Run the downloaded image:
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vincent@urdhva ~ % docker run -p 8090:8080 localhost:8080/quinistry
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2017/03/16 13:15:18 Starting quinistry
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# And download it again from itself:
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vincent@urdhva ~ % docker pull localhost:8090/quinistry
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Using default tag: latest
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latest: Pulling from quinistry
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7bf1a8b18466: Already exists
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Digest: sha256:11141d95ddce0bac9ffa32ab1e8bc94748ed923e87762c68858dc41d11a46d3f
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Status: Downloaded newer image for localhost:8090/quinistry:latest
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```
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## Building
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Quinistry creates a Docker image that only contains a statically linked `main` binary. As this package makes use of
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`net/http`, Go will (by default) link against `libc` for DNS resolution and create a dynamic binary instead.
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To disable this, `build` the project with `-tags netgo`:
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```
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go build -tags netgo
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```
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[Docker Registry V2]: https://docs.docker.com/registry/spec/api/
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[quine]: https://en.wikipedia.org/wiki/Quine_(computing)
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