Package Development and Deployment

Prerequisites: Testing

Creating a package

(@v1.13) pkg> generate Inventory
  Generating  project Inventory:
    Inventory/Project.toml
    Inventory/src/Inventory.jl

] generate creates a minimal package. PkgTemplates.jl creates a complete one — tests, GitHub Actions CI, documentation, code coverage, and a license:

# illustrative — needs the PkgTemplates package
using PkgTemplates
t = Template(user = "your-github-name", plugins = [GitHubActions(), Documenter{GitHubActions}(), Codecov()])
t("Inventory")

The development loop

(@v1.13) pkg> dev ./Inventory     # use your local copy
julia> using Revise, Inventory    # Revise reloads changes on save
julia> Inventory.total_value(...) # edit src/, call again, no restart
(Inventory) pkg> test

dev makes an environment use your working copy instead of a released version. With Revise.jl loaded first, edits to the package's source files take effect immediately.

Documentation and releases

Write docstrings for every exported name; Documenter.jl builds a website from them and runs their examples as doctests.
Follow semantic versioning in Project.toml's version field.
Register a package in the General registry with the Registrator GitHub app; TagBot then creates the Git tag and release.
Add [compat] bounds for every dependency — the registry requires them.

Load time and precompilation

Packages are precompiled when installed, and since Julia 1.9 native code is cached too. You can make the first call of your package fast by running a representative workload during precompilation with PrecompileTools.jl:

# illustrative — inside src/Inventory.jl
using PrecompileTools

@setup_workload begin
    items = [Item("pen", 3, 1.5)]
    @compile_workload begin
        total_value(items)
    end
end

Deploying applications

Scripts and services — ship the project with its Manifest.toml and run julia --project -e 'using Pkg; Pkg.instantiate()' on the server (or in a Docker image built from the official julia image).
PackageCompiler.jl — create_sysimage bakes packages into a custom system image for near-instant startup; create_app builds a relocatable application folder.
JuliaC.jl and the --trim option (experimental since Julia 1.12) compile a program into a small standalone executable by removing code it can't reach.
Web services — Oxygen.jl and Genie.jl are web frameworks; HTTP.jl is the underlying client and server.
Notebooks and dashboards — publish Pluto notebooks as static HTML, or build interactive apps with Genie or Dash.jl.