README File: Why Your Internal Projects Should Maintain One
22 Jun 2022 | Charles Flatt
README.md file that’s typically at the root of Git repositories, especially when using GitHub, GitLab, BitBucket, and Azure DevOps is well known to most developers. The purpose, structure and overall usefulness of the README file will depend on many factors, such as the project type and audience.
This article specifically addresses the Readme file that you use in your on-premise repositories. That is, your organization’s internal projects.
Internal projects’ Readme files are too often ignored. If they have a concrete and central purpose, they won’t be.
While this is not a “Complete and Authoritative 10 Steps to Perfect Readme Files.” It’s intended to be a good starting point.
Why Should I Want a README File?
The Readme file should be the starting point for your code’s users. For open source, it starts with what the code is for and how to use it. It ends with information on how to build the code.
Internal projects have a different audience and different priorities. They are
- Help a new developer get the code working on her workstation.
- Be the source of truth for continuous integration (CI).
- Be the source of truth for the environment’s version numbers.
Luckily these go hand-in-hand(-in-hand). The point of the build portion of CI is to prove the code can be built on a clean workstation.
There are two parts to getting your code building and running on a clean workstation:
- Configure the Environment the code will build in. These are external dependencies.
- Get and Build the code along with its internal dependencies.
How do I communicate the Environment?
The Environment will be the operating system and global installations required by your application. In Azure DevOps Pipeline parlance, they’re the build agent’s capabilities. Here’s an example for a solution that includes an Angular application and a .NET Core WebApi.
## Environment > Changing the environment? Change the CI/CD pipeline! Install | Version ---------------------------------|------------ Node | 14.15.3 NPM | deps on Node Angular CLI | 11.2.3 Azure Authentication | latest Visual Studio (recommended) | VS 2019+
One way to think of this is: “If my repo has a build script, what do I not want it to manage?”
Your app’s build script shouldn’t try to install Node or Angular. It shouldn’t even check if they exist. The first-use developer, or the person creating the CI pipeline, should refer to the Readme for environment details. The contract is that the environment will exist and the build script doesn’t need to verify it.
It’s easy, with Node apps, to know if it’s an environment package. It gets installed globally using
npm install -g
I recommend the table above being the Readme’s only place version numbers exist for those dependencies. It’s the source of truth. If you opt to include them in the Getting Started instructions, you need to remember to find/replace whenever the version numbers change.
Regardless, the Readme is the source of truth for environment version information.
How do I communicate Getting Started?
An excellent practice is to create a build script that will be used by the CI pipeline. This same script should be run before pushing the final commits for a pull request. This way, the CI process is being tested in advance.
At its very simplest, a .NET Core solution’s build script could look like this:
dotnet build MySolution.sln -c Release -t:Rebuild dotnet publish MySolution.sln -c Release --output "package" cd my-angular-app npm run my-angular-app:build:production
This rebuilds the solution and publishes the .NET assemblies to a “package” folder. The Angular app is built and published to its standard
dist folder. In your own organization, the script may also run tests, recreate a database, etc. The point is, there’s just one step to take.
From an onboarding viewpoint, this is great. The steps are basically “clone the repo, run the build script.”
Our Getting Started section could look like this. Note that I’m recommending
nvm-windows to the developer. This script also configures the Azure authentication to an Azure Artifacts package source.
## Getting Started > Be sure to use the correct versions from above **Environment** 1. Install PowerShell Core. 1. Install NVM or NVM for Windows. 1. Open a PowerShell *administrator* shell: ```powershell nvm install [version] nvm use [version] ``` 1. Open a PowerShell *user* shell ```powershell # Angular npm install -g @angular/cli@[version] # Azure Auth npm install -g vsts-npm-auth ``` **Application** ```powershell # Clone source cd "C:\users\[user]\source\repos" git clone https://corporate/repo/path/MyApp.git cd MyApp # Set credentials for company packages server vsts-npm-auth -config MyApp/my-angular-app/.npmrc # Build for local development ./build.ps1 ```
Again, I’m only indicating version numbers so that there’s reduced chance of the version numbers in the Environment table not matching the version numbers in Getting Started. Of course, if you trust everyone to find/replace, there’s nothing wrong with including them.
Why is this valuable to CI/CD?
The Getting Started steps are, basically, what the CI/CD pipeline should use, too. Here’s what a simple Azure YAML file might look like for our solution. The steps are virtually identical.
trigger: main pool: vmImage: 'ubuntu-latest' stages: - stage: build_stage displayName: 'Build' jobs: - job: steps: # Environment capabilities - task: NodeTool@0 displayName: 'Install Node.js' inputs: versionSpec: '14.15.3' - pwsh: 'npm install -g @firstname.lastname@example.org' displayName: 'Install Angular CLI' - task: npmAuthenticate@0 displayName: Authenticate to Azure Artifacts NPM inputs: workingFile: $(System.DefaultWorkingDirectory)/my-angular-app/.npmrc # Build - pwsh: ./build.ps1 displayName: 'Run build script' # Publish - publish: $(System.DefaultWorkingDirectory)/package artifact: package displayName: Publish - stage: deploy_to_build_stage # etc
An example README File template
# My Awesome App ## Introduction What the app is for. ## Environment > Changing the environment? Change the CI/CD pipeline! Install | Version ---------------------------------|------------ .NET Framework | 4.8 PowerShell Core | 7.x Visual Studio (recommended) | VS 2019+ Sources: * [.NET Framework](https://dotnet.microsoft.com/download/dotnet-framework) * [PowerShell Core](https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell-core-on-windows) ## Getting Started > Be sure to use the correct versions from above. **Environment** 1. Install PowerShell Core [version]. 1. Install .NET Framework [version]. **Application** ```powershell # Clone source cd "C:\users\[user]\source\repos" git clone [path-to-repo] cd [appname] # Build app ./build.ps1 ``` ## Daily Development Things needed to smoothly develop, such as how to run service dependencies. ## When to run the build script ```powershell ./build.ps1 ``` The build script simulates what the CI server will do, and is intended to catch build errors before they get to the server. The script should be run before the "final" PR commit. That is: 1. Before pushing the final feature branch, AND/OR 1. Before pushing to the mainline branch ## Troubleshooting Things that might go wrong. These SHOULD end up on product backlogs and get fixed.
The Key Values of a README File
The key values of a Readme for internal projects are:
- Source of truth for environment dependency version numbers
- Rapid developer onboarding
- Matching steps used for building locally and in CI/CD
How can you keep this up-to-date? While I’m not hoping your turnover is high, whenever a new developer is brought on they should try to get the application working using just the documentation, and update if needed.