This tool enables the automated rebuilding of the codelabs in this repository via a yaml configuration file.

To make it easy to use this tool, you can install the tool in your global pub executable cache by running the following command from this project directory.

$ dart pub global activate --source path .

Running the tool requires a codelab_rebuild.yaml file. There are examples of these configuration files in the codelabs in this repository. To run the tool on the adaptive_app codelab, run the following commands:

$ cd ../..    # go back to the root of the flutter/codelabs checkout
$ codelab_rebuild adaptive_app/codelab_rebuild.yaml

At the top level, the codelab_rebuild.yaml configuration file contains two keys, name for the name of the script, and steps which is the collection of steps required to rebuild the codelab.

Individual steps can have a variety of attributes, which control what the step does. All steps must have a name which is output during the run. This is primarily for debugging a script when things break.

Steps may have a steps for a list of sub steps, in which case it can't have any other attributes. Steps within steps can go as deep as required.

For removing a file there is rm, removing a directory rmdir, creating a directory there is mkdir, each of which takes as the value the path to the file or directory to create or remove.

For modifying the content of files there are two approaches. For replacing the contents of a file, there is replace-contents key which takes the new contents of the file as the value. Note, if the file doesn't exist, replace-contents will
create the file. To specify the file to be modified you must also set the path key with the relative path to the file.

Alternatively there is the patch family of keys, which are fed to the patch command to update the file nominated by the path key. After much trial and error I have stabilised on using patch-u (unified diffs), generated with the help of the git diff command.

For running flutter and dart commands there are appropriate keys. Use the path key to nominate the working directory in which to run the flutter or dart command.

There is a platforms key to restrict which platforms a step will be run on. This is useful for specifying that specific flutter commands are only run on platforms that support that form of executable. No point trying to build an iOS Flutter app on MS Windows.