79 lines
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4 KiB
Markdown
79 lines
No EOL
4 KiB
Markdown
# Development Report for July 17, 2017
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### BuildKit
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[Repo](https://github.com/moby/buildkit)
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[Proposal](https://github.com/moby/moby/issues/32925)
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Following features were added last week:
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#### Git source
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Source code from git repositories can now be accessed directly, similarly for images can be accessed, without the need to execute `git clone`. This has many performance and caching advantages. It accesses the remote repository using shallow fetches to only pull the required data and a uses a shared bare repository for intermediate cache between build invocations. The instruction cache for the git source is based on a commit hash and not string arguments. This means that you can always be sure that you are building the correct source and that you never build the same source twice.
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#### Containerd exporter
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Exporters are used for getting build artifacts out of buildkit. The first exporter that was implemented allows exposing the image to containerd so it can be run and pushed with `ctr` tool. `buildctl` has `--exporter` flag for specifying the exporter and `--exporter-opt` for custom values passed to the exporter. In the case of image exporter an image name can be specified.
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For example:
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```
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go run ./examples/buildkit2/buildkit.go | buildctl build --exporter image --exporter-opt name=docker.io/moby/buildkit:dev
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```
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Accessing from ctr/dist:
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```
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ctr --namespace buildkit images ls
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ctr --namespace buildkit rootfs unpack <manifest-sha>
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ctr --namespace buildkit run -t docker.io/moby/buildkit:dev id ash
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```
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#### Local source
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Buildkit now supports building from local sources. Snapshot of the local source files is created similarly to `docker build` build context. The implementation is based on the [incremental context send](https://github.com/moby/moby/pull/32677) feature in `docker-v17.07`. To use in `buildctl` the source definition needs to define a name for local endpoint, and `buildctl build` command provides a mapping from this name to a local directory with a `--local` flag.
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```
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go run ./examples/buildkit3/buildkit.go --local | buildctl build --local buildkit-src=.
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```
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### Typed Dockerfile parsing
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[PR](https://github.com/moby/moby/pull/33492)
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Didn't manage to merge this PR yet. Still in code-review.
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### Feedback for `RUN --mount` / `COPY --chown`
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There was some new discussion around [`RUN --mount`](https://github.com/moby/moby/issues/32507) or [`COPY --chown`](https://github.com/moby/moby/issues/30110) feature. Currently, it seems that it may be best to try the shared cache capabilities described in `RUN --mount` in https://github.com/moby/buildkit first(it already supports the generic mounting capabilities). So to unblock the people waiting only on the file owner change features it may make sense to implement `COPY --chown` first. Another related candidate for `v17.08` release is https://github.com/moby/moby/issues/32816.
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### Proposals for new Dockerfile features that need design feedback:
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[Add IMPORT/EXPORT commands to Dockerfile](https://github.com/moby/moby/issues/32100)
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[Add `DOCKEROS/DOCKERARCH` default ARG to Dockerfile](https://github.com/moby/moby/issues/32487)
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[Add support for `RUN --mount`](https://github.com/moby/moby/issues/32507)
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[DAG image builder](https://github.com/moby/moby/issues/32550)
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[Option to export the hash of the build context](https://github.com/moby/moby/issues/32963) (new)
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[Allow --cache-from=*](https://github.com/moby/moby/issues/33002#issuecomment-299041162) (new)
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[Provide advanced .dockeringore use-cases](https://github.com/moby/moby/issues/12886) [2](https://github.com/moby/moby/issues/12886#issuecomment-306247989)
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New: [RFC: Distributed BuildKit](https://github.com/moby/buildkit/issues/62)
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If you are interested in implementing any of them, leave a comment on the specific issues.
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### Builder features currently in code-review:
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[Fix shallow git clone in docker-build](https://github.com/moby/moby/pull/33704)
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### Backlog
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[Build secrets](https://github.com/moby/moby/issues/33343) has not got much traction. If you want this feature to become a reality, please make yourself heard. |