VersionsJSONUtil: Generate versions.json files that contain the list of Julia versions

S3 URL:

• v1: https://julialang-s3.julialang.org/bin/versions.json
• v2: [coming soon]¹

JSON Schema

schema.json contains a JSON Schema for the versions.json file.

It can be used to validate the versions file or to generate code from the schema.

nightlies.json

S3 URL: https://julialang-s3.julialang.org/bin/nightlies.json

nightlies.json is experimental: its format may still change in breaking ways.

nightlies.json is the counterpart of versions.json for in-development builds. Its top-level keys are the nightly channels in juliaup's vocabulary: nightly (builds of master) and x.y-nightly (the latest build of the x.y release series, i.e. of release-x.y once that branch exists). Each channel has a files list describing the standard builds with the same keys as versions.json (triplet, os, arch, kind, extension, url), with two differences:

• There is no version, size, sha256 or tree hash: every URL is a julia-latest-* file that is overwritten after each successful build on its branch, so nothing content-specific can be recorded. Consumers should track changes through the server's ETag / Last-Modified headers (as juliaup does). The detached signature, when one is published, is referenced by URL in asc-url rather than inlined.
• Build variants of the standard binaries are listed in a separate variants list (absent when there are none), so that tools selecting a file from files by platform never pick up a variant by accident. Its entries have the keys of files plus variants, the names of the variants applied to that build: opt (the PGO+LTO+BOLT optimized build), assert (Julia and LLVM assertions enabled) and nogpl (no GPL-licensed dependencies). Every build currently has a single variant; the list leaves room for combinations.

schema-nightlies.json contains its JSON Schema. See the devdocs for how the file is generated.

Downstream tools using versions.json

This is a (not necessarily complete) list of known tools that make use of versions.json. If you maintain such a tool, please make a PR to add it to this list. This allows us to check if changes might break downstream tooling.

• abelsiqueira/jill: A Julia installer written in Bash.
• johnnychen94/jill.py: A Julia installer written in Python.
• nhz2/install-julia-linux: A Julia installer written in Shell.
• julia-actions/setup-julia: Installs Julia in GitHub Actions CI jobs.
• JuliaCI/julia-buildkite-plugin: Buildkite plugin to install Julia for use in a pipeline. This plugin is used in Base Julia CI.
• JuliaCI/julia-snap: Snap setup for Julia.
• JuliaCI/PkgEval.jl: A package to test one or more Julia versions against the Julia package ecosystem.
• JuliaLang/Juliaup: Julia installer and version manager².
• JuliaLang/www.julialang.org: The Julia website repo (uses versions.json to auto-generate the list of Julia releases).

Devdocs

See ./devdocs/README.md.

Background and motivation

This issue provides background info that explains the motivation: JuliaLang/julia#33817

Footnotes

1. v2 is not available yet. When it becomes available, the S3 URL will probably be https://julialang-s3.julialang.org/bin/versions.v2.json ↩

2. This means that every tool that uses Juliaup is indirectly downstream of versions.json. ↩