7. Registries

Registries contain information about packages, such as available releases and dependencies, and where they can be downloaded. The General registry is the default one, and is installed automatically if there are no other registries installed.

Managing registries

Registries can be added, removed and updated from either the Pkg REPL or by using the functional API. In this section we will describe the REPL interface. The registry API is documented in the Registry API Reference section.

Adding registries

A custom registry can be added with the registry add command from the Pkg REPL. Usually this will be done with a URL to the registry.

If a custom registry has been installed causing the General registry to not be automatically installed, it is easy to add it manually: be added automatically. In that case, we can simply add the General

pkg> registry add General

and now all the packages registered in General are available for e.g. adding. To see which registries are currently installed you can use the registry status (or registry st) command

pkg> registry st
Registry Status
 [23338594] General (https://github.com/JuliaRegistries/General.git)

Registries are always added to the user depot, which is the first entry in DEPOT_PATH (cf. the Glossary section).

Removing registries

Registries can be removed with the registry remove (or registry rm) command. Here we remove the General registry

pkg> registry rm General
  Removing registry `General` from ~/.julia/registries/General

pkg> registry st
Registry Status
  (no registries found)

In case there are multiple registries named General installed you have to disambiguate with the uuid, just as when manipulating packages, e.g.

pkg> registry rm General=23338594-aafe-5451-b93e-139f81909106
  Removing registry `General` from ~/.julia/registries/General

Updating registries

The registry update (or registry up) command is available to update registries. Here we update the General registry:

pkg> registry up General
  Updating registry at `~/.julia/registries/General`
  Updating git-repo `https://github.com/JuliaRegistries/General`

and to update all installed registries just do:

pkg> registry up
  Updating registry at `~/.julia/registries/General`
  Updating git-repo `https://github.com/JuliaRegistries/General`

Registries automatically update once per session when a package operation is performed so it rarely has to be done manually.

Registry format

In a registry, each package gets its own directory; in that directory are the following files: Compat.toml, Deps.toml, Package.toml, and Versions.toml. The formats of these files are described below.

Registry Compat.toml

The Compat.toml file has a series of blocks specifying version numbers, with a set of dependencies listed below. For example, part of such a file might look like this:

["0.8-0.8.3"]
DependencyA = "0.4-0.5"
DependencyB = "0.3-0.5"

["0.8.2-0.8.5"]
DependencyC = "0.7-0"

Dependencies that are unchanged across a range of versions are grouped together in these blocks. The interpretation of these ranges is given by the comment after each line below:

"0.7-0.8"  # [0.7.0, 0.9.0)
"0.7-0"    # [0.7.0, 1.0.0)
"0.8.6-0"  # [0.8.6, 1.0.0)
"0.7-*"    # [0.7.0, ∞)

So for this package, versions [0.8.0, 0.8.3] depend on versions [0.4.0, 0.6.0) of DependencyA and version [0.3.0, 0.6.0) of DependencyB. Meanwhile, it is also true that versions [0.8.2, 0.8.5] require specific versions of DependencyC (so that all three are required for versions 0.8.2 and 0.8.3).

Registry flavors

The default Pkg Server (pkg.julialang.org) offers two different "flavors" of registry.

• conservative: suitable for most users; all packages and artifacts in this registry flavor are available from the Pkg Server, with no need to download from other sources
• eager: this registry offers the latest versions of packages, even if the Pkg and Storage Servers have not finished processing them; thus, some packages and artifacts may not be available from the Pkg Server, and thus may need to be downloaded from other sources (such as GitHub)

The default registry flavor is conservative. We recommend that most users stick to the conservative flavor unless they know that they need to use the eager flavor.

To select the eager flavor:

ENV["JULIA_PKG_SERVER_REGISTRY_PREFERENCE"] = "eager"

import Pkg

Pkg.Registry.update()

To select the conservative flavor:

ENV["JULIA_PKG_SERVER_REGISTRY_PREFERENCE"] = "conservative"

import Pkg

Pkg.Registry.update()

Creating and maintaining registries

Pkg only provides client facilities for registries, rather than functionality to create or maintain them. However, Registrator.jl and LocalRegistry.jl provide ways to create and update registries, and RegistryCI.jl provides automated testing and merging functionality for maintaining a registry.