Building your projects
Build phases
Projen defines a standard way for building software through a fixed set of build phases. This is implemented via a set of tasks defined in the Project base class which all constructs extend from.
The build task contains a set of sub-tasks which represent the various build phases:
- default - responsible for running your projenrc and synthesizing all project files.
- pre-compile - runs before compilation (eg. bundle assets).
- compile - compiles your code (if needed).
- post-compile - runs immediately after a successful compilation.
- test - runs tests.
- package - creates a distribution package.
To extend the build process, components and projects can use project.projectBuild.xxxTask and interact with the Task object (for example, project.projectBuild.postCompileTask.exec("echo hi") will run `echo hi`` after compilation).
Note
The build task itself is locked. This means that any attempt to extend it (i.e. call spawn, exec, reset, etc) will throw an exception. We recommend just extend one of the phases instead of extending the build. This ensures that phases are always executed in the right order.
Sourced from: https://projen.io/build.html
Modifying tasks
Adding a new task
To add a new task to a project, add the following in your projenrc file:
const helloTask = project.tasks.addTask("hello");
helloTask.exec("echo world");
After you synthesize this change, you can call your task by executing npx projen hello.
Tip
If you have the pdk CLI installed, you can also invoke your task by running pdk hello
Changing a task
Resetting a task removes any commands which may have already been configured (for example default commands provided by the projen project being used). You can reset a task as follows:
const someTask = project.tasks.tryFind("<some-task>")?.reset();
someTask.exec('echo something');
someTask.spawn(someOtherTask);
This will make the <some-task> task a no-op. You can then add your own steps by calling exec/spawn on the task.
Tip
The default phase tasks are available directly within the project as they always exist and can be referenced like project.compileTask.
Full build
In order to perform a full build of your codebase, run the npx projen build command from the root of your monorepo. This will build each of your projects in the dependency order.
The npx projen build command is a convenience wrapper around an underlying nx run-many --target=build --output-style=stream --nx-bail command. You can pass in any options available in the nx cli, for example npx projen build --parallel=10 will perform the build with up to 10 parallel processes.
Targeted build
In order to perform a targeted build of a single package and its dependencies, run the npx nx run <package-name>:build command. This will build the package-name and all of its dependencies in the correct dependency order.