title: Apache Mesos - Using cquery for Code Navigation layout: documentation

Using cquery for Code Navigation

Instead of using grep and other tools to find your way through the Mesos codebase, you can use cquery on Windows, Linux, and macOS!

Tested and designed for large code bases like Chromium, cquery provides accurate and fast semantic analysis for any editor that supports the Language Server Protocol.

Using cquery provides IDE features like these (and more):

  • Find definitions and references
  • Contextual completion candidates
  • On-the-fly syntax checking
  • Preprocessor skipped regions
  • Symbol documentation
  • Hover information

Although the cquery wiki provides a getting started guide for building from source, generating the compilation information for your project, and setting up your editor, this guide covers setup specifically for Mesos using CMake. Feel free to refer to the wiki for further information, but what follows is the recommended setup.

NOTE: Do not use the released binaries as the latest, v20180302, is still built Clang 5 instead of Clang 6, which is buggy with Mesos.

Building cquery from source

The cquery project is currently switching to CMake, but the guide still uses the waf build tool. Since we need to use CMake for Mesos too, it easier to use it for both. More information can be found on the wiki:

  1. Install CMake following the instructions here.
  2. Install Ninja by downloading the latest release for your platform and placing it in your path (optional for non-Windows platforms, but highly recommended).
  3. If you're on Windows, make sure build in an “x64 Native Tools Command Prompt for VS 2017”.
git clone --recursive https://github.com/cquery-project/cquery
cd cquery && mkdir build && cd build
cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release

There should now exist a binary cquery (or cquery.exe on Windows) in the build folder of the cquery repo. When configuring your editor, you need to make sure this can either be found automatically via your PATH, or point the editor's plugin toward it.

Generating compilation information for Mesos

The next step is to generate a compile_commands.json file for Mesos. Fortunately, this can be done automatically using CMake. In fact, the instructions are (almost) identical to the instructions above. Once generated, either symlink or copy it to the root of the Mesos repository.

git clone https://gitbox.apache.org/repos/asf/mesos.git
cd mesos && mkdir build && cd build
cd ..
ln -s build/compile_commands.json .

The CMake option CMAKE_EXPORT_COMPILE_COMMANDS also supports the Makefile generator on Linux, if you wish to use it instead of Ninja, but the author has not tested this scenario, and recommends Ninja anyway as it builds faster. On Windows, Ninja is the only generator which supports exporting the compilation commands.

Note that for cquery to work properly, an initial build must be completed because of our third-party dependencies, otherwise many of the project's required headers will be missing.

Setting up your editor

Finally, your editor's cquery / LSP plugin needs to be set up. Information for other editors can be found at Langserver.org. Once you have LSP setup, it can be used for other languages too by switching out the cquery backend with one specific for the language.


For Emacs, the packages lsp-mode and lsp-ui are recommended.

A sample (but complete) Emacs configuration which sets up syntax checking and auto-completions with LSP and cquery looks like this:

;; Generic Emacs package repo setup
(require 'package)
 '(("melpa" . "https://melpa.org/packages/")
   ("gnu" . "https://elpa.gnu.org/packages/")))

;; Used to install and configure Emacs packages.
;; I forgot the old way since using this.
;; https://github.com/jwiegley/use-package
(unless (package-installed-p 'use-package)
  (package-install 'use-package))

  (require 'use-package))

;; Syntax checking.
;; Should be automatic.nn
;; http://www.flycheck.org/en/latest/
(use-package flycheck
  :ensure t

;; Auto-completions.
;; There's also `C-M-i`, but this is async.
;; Also look at `company-flx` for better sorting.
;; https://company-mode.github.io/
(use-package company
  :ensure t

;; Language Server Protocol Plugin.
;; The actual plugin used to communicate with cquery.
;; https://github.com/emacs-lsp/lsp-mode
(use-package lsp-mode
  :ensure t)

;; Flycheck and other IDE-feature support for LSP.
;; This has the "fancy features" and should be customized.
;; Personally, I turned the symbol highlighting off.
;; https://github.com/emacs-lsp/lsp-ui
(use-package lsp-ui
  :ensure t
  (add-hook 'lsp-mode-hook #'lsp-ui-mode))

;; LSP backend for Company.
;; https://github.com/tigersoldier/company-lsp
(use-package company-lsp
n  :ensure t
  (setq company-lsp-enable-recompletion t)
  (add-to-list 'company-backends 'company-lsp))

;; Client to configure and auto-start cquery.
;; https://github.com/cquery-project/emacs-cquery
(use-package cquery
  :ensure t
  (add-hook 'c-mode-common-hook #'lsp-cquery-enable)
  (setq cquery-executable "/path/to/cquery/build/cquery")
  (setq cquery-extra-init-params '(:completion (:detailedLabel t))))

Being Emacs, feel free to customize to your liking. The author's configurations can be found here. While auto completion, syntax checking, and other UI improvements are automatic, you should also be aware of M-. for xref-find-definitions; M-? for xref-find-references; M-, to pop back before using xref; imenu to list an index of functions, namespaces, etc.; and the customization options of lsp-ui, as it will automatically turn on a sideline and symbol highlighting, which can be noisy.


An LSP plugin exists; if you set it up, please add the steps here.

Visual Studio Code

A cquery specific extension exists; if you set it up, please add the steps here.

Sublime Text

An LSP package exists; if you set it up, please add the steps here.