Zed Rego Extension

Zed extension for the Rego policy language from Open Policy Agent (OPA).

See the blog introducing the zed-rego extension if you want to learn more about the background and motivation for this extension, as well as a detailed overview of its features.

Features

Rego Syntax Support

Basic features like syntax highlighting and indentation works out of the box. More advanced features are provided by Regal.

Regal Language Server Support

This extension uses the Regal language server for Rego to provide most of its functionality. The following features of the language server are currently supported:

• Diagnostics (linting)
• Hover (inline docs on built-in functions)
• Go to definition (cmd + click on a reference to go to definition)
• Folding ranges (expand/collapse blocks, imports, comments)
• Document and workspace symbols (cmd+t to navigate to rules, functions, packages)
• Inlay hints (but may need to be enabled in settings "Toggle inlay hints")
• Formatting
• Code actions
• Code completion
• Code lenses (click to evaluate package or rule) - not yet supported by Zed

To learn more about each language server feature provided, see the Regal language server documentation.

Installation

This extension is available in the Zed extension marketplace, and you'll find it by searching for "rego" in the extensions view.

Since the extension makes use of Regal for language server features, the extension will automatically try to download the latest version of Regal to use, unless the regal binary is found on $PATH.

If you want to have updates of Regal managed automatically, you can use Homebrew to install the regal binary instead (MacOS & Linux):

brew install styrainc/packages/regal

Tasks

This extension additionally provides two tasks for running tests. Note that both of the tasks assume that the workspace can be read as a bundle (similarly to what the OPA extension for VS Code expects).

opa test (workspace)

Runs all tests found in the workspace. This is a normal task made available in the command palette (task: spawn).

opa test (single test)

This is a special task (called a runnable) which is made available inside of test packages, and where a "play" button will appear next to any test rule. Pressing this button will run only that test.

opa eval ?

The opa eval command requires a query containing the full path to what should be evaluated. This is commonly the package path + the name of the rule to be evaluated. While we can use a tree-sitter query to extract the rule name — like we do for running single tests — we have yet to understand if it's possible / how to extract both the package path and the rule name and concatenate them to build a query.

You can however easily create a custom task for opa eval where you provide the query yourself, and use that in your project. Such a task may look something like the example below:

.zed/tasks.json

[
  {
    "label": "opa eval (data.policy.main)",
    "command": "opa",
    "args": ["eval", "--bundle", "$ZED_WORKTREE_ROOT", "--input", "$ZED_WORKTREE_ROOT/input.json", "data.policy.main"],
  }
]

Custom Tasks

See the Zed documentation tasks for information about how to easily add your own custom tasks, either globally or to a specific project. These docs also details which environment variables are available in the task execution context.

Development

See the docs on contributing if you're interested in hacking on this extension.

Credits

• Tree-sitter grammar provided by the tree-sitter-rego project
• Language server for Rego provided by Regal

Community

For questions, discussions and announcements related to Styra products, services and open source projects, please join the Styra community on Slack!