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Installing Forem on macOS

This spins up a Forem stack for local development with no use of containerization, virtualization, etc., which comes with tradeoffs: standing up the stack will almost invariably be a slower process as various tools build from source, but attaching debuggers and the like to the resulting Forem application will be easier, not to mention the lack of I/O overhead that comes with, for example, running a full Linux VM to run containers in (which, for example, Docker Desktop does). However, more cruft gets left behind when you're done working: you'll have PostgreSQL databases and so forth to clean up. If you'd rather take the containers side of the tradeoffs, those docs are here.

For maintainer sanity reasons, this opinionated and curated instruction set assumes you're cool with the use of Homebrew to install certain system-wide dependencies, and mise to install specific versions of Ruby, NodeJS, Yarn (a JS package manager), PostgreSQL (a database), and Redis (an in-memory cache) that are tricky to version-lock system-wide. If these package managers are for any reason a non-starter for you, you'll want to use your package management solutions of choice to install the tools found in .mise.toml, .ruby-version, and .nvmrc, at the appropriate versions, and should be comfortable sorting out the dependencies thereof on your own.

This has been tested on Apple Silicon Macs, but should be expected to work without noteworthy modification on Intel Macs. If you find a setup issue on Intel Macs, file an issue with us.

Installing Package Managers

To start, we need to install (two of the three...) package managers that we'll use later in the guide: Homebrew and mise. Follow whatever their current instructions are at those links, and then come back here. Notably for mise, make sure you've configured the appropriate shell integration (you probably should have seen something about eval and a bashrc or zshrc!).

Pulling Forem's Code

Using Homebrew (or alternative means, if desired), we need to install git a version control system we use in the development of Forem (with GitHub as our canonical host for the Git repository), and then this section is reasonably straightforward.

Those with the Xcode Command Line Tools already installed, for example those using AWS EC2 Mac instances in the cloud, will alerady have a working Git install at /usr/bin/git. That's fine: let's install Homebrew's version anyway, for consistency, unless you really know what you're doing.

  1. brew install git
  2. Fork Forem's repository using this GitHub link. Forking is optional to read our code, but will be necessary to submit changes to us, so this is a helpful bit of upfront house-keeping.
  3. Clone your forked repository:
  • With HTTPS: git clone<your-username>/forem.git
  • With SSH: git clone<your-username>/forem.git
  • Or, use a graphical Git client of your choosing, the selection of which is outside the scope of this document.
  1. Then, change directories into the clone: cd forem

Installing System-Level Dependencies

This is the part where, if you've opted out of Homebrew, you'll need to round up a few tools on your own. Most notably, ImageMagick is somewhat non-trivial.

Homebrew makes this step quick: run brew bundle, and assuming it finishes successfully, you're done. This step should only fail if Homebrew is not installed correctly, or there is a version conflict between what we depend on for Forem, and whatever you might already have installed on your system (gpg is a potential candidate here). In the event of such a collision, you can either uninstall the existing package on your system, or skip the failed package for now and attempt to complete these setup instructions anyway. It might work. If not, open an issue with us and we'll see if we can help.

Installing Version-Locked Tool Dependencies

This is the part where, if you've opted out of mise, you'll need to round up tools on your own. For Ruby, consider setting up rbenv using their installation guide and then installing our current Ruby version target with rbenv install $(cat .ruby-version). For NodeJS, consider nvm and install our Node version target with nvm install. You're on your own for installing Yarn v1, PostgreSQL v13 (perhaps via, also see our auxiliary documentation), and Redis.

Use mise install - this will pull the exact versions we recommend for the tools listed in the block above, which helps to prevent "version drift" - where someone writes code targeting Version A of some tool, but it breaks when run against Version B of that same tool.

If prompted, respond y to the prompts about installing plugins to handle Yarn, PostgreSQL, and Redis.

This step will probably take several minutes: it's building most of these dependencies from source code. Errors at this point are unlikely, but if they pop up, should be expected to be quite varied: searching for error messages will often lead to helpful solutions, as few to none of these errors are likely to have never been seen (and triaged) before.

Last Bits Of Setup

  1. Start the caching server with redis-server --daemonize yes (do this every time you work on Forem!)

  2. Start and configure the database (which requires some tinkering to avoid future errors; copy pasting is fine here!)

  • pg_ctl start - do this every time you work on Forem!

  • createuser -U postgres -s $(whoami), which creates a PostgreSQL user by your system username. This only needs done once.

  • Now we need to change the default encoding of the database. These steps are copied nearly verbatim from the Arch Linux wiki. Run them one-by-one.

    • psql -d postgres -c "UPDATE pg_database SET datistemplate = FALSE WHERE datname = 'template1';"
    • psql -d postgres -c "DROP DATABASE template1;"
    • psql -d postgres -c "CREATE DATABASE template1 WITH TEMPLATE = template0 ENCODING = 'UNICODE';"
    • psql -d postgres -c "UPDATE pg_database SET datistemplate = TRUE WHERE datname = 'template1';"
  1. Set up your environment variables/secrets

    • Take a look at .env_sample to see all the ENV variables we use and the fake default provided for any missing keys. If you don't need to override any environment variables, continue with the next step as our setup script will automatically create a default .env file.

    • If you use a remote computer as dev env, you need to set APP_DOMAIN variable to the remote computer's domain name.

    • The backend guide will show you how to get free API keys for additional services that may be required to run certain parts of the app.

    • For any key that you wish to enter/replace, follow the steps below.

      1. Create .env by copying from the provided template (i.e. with bash: cp .env_sample .env). This is a personal file that is ignored in git.
      2. Obtain the development variable and apply the key you wish to enter/replace. i.e.:
    • You do not need "real" keys for basic development. Some features require certain keys, so you may be able to add them as you go. The test environment is isolated from changes to the .env file, if you want to set variables in both test and development, use a file named .env.local, or modify .env.test.local and .env.development.local.

  2. Do final application setup (including the installation of requisite Ruby gems and NodeJS modules) with ./bin/setup.

Start Up Your Forem!


Presuming no errors here, your Forem should be accessible at http://localhost:3000.

To run unit tests, first, prepare the database:

./bin/rails db:test:prepare RAILS_ENV=test

Then, try running any test, for example:

./bin/rspec spec/lib/acts_as_taggable_on

To shut down your Forem stack when you're done tinkering, shut services down in the inverse order of how we started them:

  • Press Ctrl-C to stop the Forem server process that's currently in the foreground
  • pg_ctl stop will shut down the database
  • redis-cli SHUTDOWN will stop the caching server

Possible error messages

This section serves as a collection of various things that have gone wrong in the past while setting up Forem on Macs: not all of them are necessarily common anymore, and in particular many of them impact rbenv-based setups more than mise-based setups (so far), but they're preserved here just in case.

Error: rbenv install hangs at ruby-build: using readline from homebrew

Solution: Stackoverflow answer RUBY_CONFIGURE_OPTS=--with-readline-dir="$(brew --prefix readline)" rbenv install 2.0.0

Error: __NSPlaceholderDate initialize] may have been in progress in another thread when fork() was called


Error: User does not have CONNECT privilege.

Solution: Complete the steps outlined in the PostgreSQL setup guide.

Error: rbenv: version '<version number>' is not installed (set by /Path/To/Local/Repository/.ruby-version)

Solution: Run the command rbenv install <version number>

Error: ruby-build: definition not found: <version number> when rbenv was installed via brew.

ruby-build: definition not found: <version number>

See all available versions with `rbenv install --list`.
If the version you need is missing, try upgrading ruby-build:

Solution: Run the following to update ruby-build, brew update && brew upgrade ruby-build. After that, rerun rbenv install <version number> and that version will get installed.


== Preparing database ==
Sorry, you can't use byebug without Readline. To solve this, you need to
rebuild Ruby with Readline support. If using Ubuntu, try `sudo apt-get
install libreadline-dev` and then reinstall your Ruby.
rails aborted!
LoadError: dlopen(/Users/<username>/.rbenv/versions/2.6.5/lib/ruby/2.6.0/x86_64-darwin18/readline.bundle, 9): Library not loaded: /usr/local/opt/readline/lib/libreadline.<some version number>.dylib

Solution: Run ln -s /usr/local/opt/readline/lib/libreadline.dylib /usr/local/opt/readline/lib/libreadline.<some version number>.dylib from the command line then run bin/setup again. You may have a different version of libreadline, so replace <some version number> with the version that errored.


PG::Error: ERROR:  invalid value for parameter "TimeZone": "UTC"
: SET time zone 'UTC'

Solution: Restart your, or, if you installed PostgreSQL with Homebrew, restart with:

brew services restart postgresql

If that doesn't work, reboot your Mac.


ERROR:  Error installing pg:
ERROR: Failed to build gem native extension.
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***

Solution: You may encounter this when installing PostgreSQL with the Try restarting the app and reinitializing the database. If that doesn't work, install PostgreSQL with Homebrew instead: brew install postgresql


node-pre-gyp ERR! stack Error: Failed to execute '/Users/yourusername/.nvm/versions/node/v14.17.6/bin/node /Users/yourusername/.nvm/versions/node/v14.17.6/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js configure --fallback-to-build --module=/Users/yourusername/Code/forem/node_modules/canvas/build/Release/canvas.node --module_name=canvas --module_path=/Users/yourusername/Code/forem/node_modules/canvas/build/Release --napi_version=8 --node_abi_napi=napi --napi_build_version=0 --node_napi_label=node-v83 --python=/opt/homebrew/opt/python@3.9/bin/python3' (1)


On an M1 Mac, this is due to there not being a prebuilt release for the node-canvas JavaScript package. You can get it to build itself from source if you install the following packages via the arm64 version of Homebrew:

brew install pkg-config cairo pango libpng jpeg giflib librsvg

If you encountered any errors that you subsequently resolved, please consider updating this section with your errors and their solutions.