Bazel and External Repositories Which version do you get? Klaus - - PowerPoint PPT Presentation

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Bazel and External Repositories Which version do you get? Klaus - - PowerPoint PPT Presentation

Sep 30, 2023 422 likes •716 views

Bazel External Repositories Bazel and External Repositories Which version do you get? Klaus Aehlig October 910, 2018 Bazel External Repositories Imagine. . . You freshly check out your project. Bazel External Repositories Imagine. . .

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SLIDE 1

Bazel External Repositories

Bazel and External Repositories

Which version do you get? Klaus Aehlig October 9–10, 2018

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SLIDE 2

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
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SLIDE 3

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
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SLIDE 4

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.

load("@bazel tools//tools/build defs/repo:git.bzl", "git repository") . . . git repository( name = "com google protobuf", remote = "https://github.com/google/protobuf", branch = "master", patch cmds = ["find .

  • name ’*.sh’ -exec . . . "],

) . . .

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SLIDE 5

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.

load("@bazel tools//tools/build defs/repo:git.bzl", "git repository") . . . git repository( name = "com google protobuf", remote = "https://github.com/google/protobuf", branch = "master", patch cmds = ["find .

  • name ’*.sh’ -exec . . . "],

) . . . Fully abstract description! Only to be changed, when a new dependency is added.

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SLIDE 6

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
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SLIDE 7

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
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SLIDE 8

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...

. . . and you build at the latest known-good snapshot!

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SLIDE 9

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
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SLIDE 10

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... for an older version of your project
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SLIDE 11

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... for an older version of your project

. . . and you build against the snapshot used at that time!

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SLIDE 12

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
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SLIDE 13

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
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SLIDE 14

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
  • resolved.bzl read instead (generated, committed!)
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SLIDE 15

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
  • resolved.bzl read instead (generated, committed!)
  • precise commit ids, instead of branches
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SLIDE 16

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
  • resolved.bzl read instead (generated, committed!)
  • precise commit ids, instead of branches
  • hashes of the generated directory

definitely the same code, even with transformations!

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SLIDE 17

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
  • resolved.bzl read instead (generated, committed!)
  • precise commit ids, instead of branches
  • hashes of the generated directory

definitely the same code, even with transformations!

  • actually, just a Starlark value
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SLIDE 18

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //...
  • WORKSPACE file ignored
  • resolved.bzl read instead (generated, committed!)
  • precise commit ids, instead of branches
  • hashes of the generated directory

definitely the same code, even with transformations!

  • actually, just a Starlark value build can use it

load("//:resolved.bzl", "resolved) for wsentry in resolved: repo = wsentry["original attributes"]["name"] for actual in wsentry["repositories"]: . . .

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SLIDE 19

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
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SLIDE 20

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
  • update dependency snapshot: bazel sync
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SLIDE 21

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
  • update dependency snapshot: bazel sync

$ bazel sync . . . INFO: Repository rule ’com google protobuf’ returned: {"commit": "c27d6a56. . . ", . . . } . . . $

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SLIDE 22

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
  • update dependency snapshot: bazel sync

$ bazel sync . . . INFO: Repository rule ’com google protobuf’ returned: {"commit": "c27d6a56. . . ", . . . } . . . $

  • WORKSPACE file fully executed, unconditionally.
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SLIDE 23

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
  • update dependency snapshot: bazel sync

$ bazel sync . . . INFO: Repository rule ’com google protobuf’ returned: {"commit": "c27d6a56. . . ", . . . } . . . $

  • WORKSPACE file fully executed, unconditionally.
  • versions (and hashes!) recorded in resolved.bzl
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SLIDE 24

Bazel External Repositories

  • Imagine. . .
  • You freshly check out your project.
  • The WORKSPACE file describes the branches followed.
  • bazel build //... (correct snapshot)
  • update dependency snapshot: bazel sync

$ bazel sync . . . INFO: Repository rule ’com google protobuf’ returned: {"commit": "c27d6a56. . . ", . . . } . . . $

  • WORKSPACE file fully executed, unconditionally.
  • versions (and hashes!) recorded in resolved.bzl
  • meaningful diff
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SLIDE 25

Bazel External Repositories

This is reality!

(as of Bazel 0.19; get the latest rc now)

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SLIDE 26

Bazel External Repositories

This is reality!

(as of Bazel 0.19; get the latest rc now) Added as an experimental opt-in, controlled by .bazelrc

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SLIDE 27

Bazel External Repositories

This is reality!

(as of Bazel 0.19; get the latest rc now) Added as an experimental opt-in, controlled by .bazelrc

sync --experimental repository resolved file=resolved.bzl build --experimental resolved file instead of workspace=resolved.bzl build --experimental repository hash file=resolved.bzl build --experimental verify repository rules=. . .

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SLIDE 28

Bazel External Repositories

The Future

We have many ideas for the future. . .

  • more rules to return versions (besides git repository)
  • meta-rules (“These packages and their dependencies”)
  • source-like vs configure-like rules
  • enable resolved.bzl by default
  • dependency discovery and install targets (autotools-like)

Probably can be done in Starlark right now.

  • . . .

. . . but we need your input to decide what is important. Talk to us!