Using Copier Answers to rerun templates quickly
===============================================

The copier answers file is a key component to making your templates re-runnable. Let's look at the example for my setup.py.

Date: January 8, 2022

The copier answers file is a key component to making your templates
re-runnable. Let's look at the example for my setup.py.

``` bash
❯ tree ~/.copier-templates/setup.py
/home/walkers/.copier-templates/setup.py
├── [[ _copier_conf.answers_file ]].tmpl
├── copier.yml
├── setup.cfg
└── setup.py.tmpl

0 directories, 4 files
```

Inside of my `[[ _copier_conf.answers_file ]].tmpl` file is this, a
message not to muck around with it, and the ansers in yaml form. The
first line is just a helper for the blog post.

``` yaml
# ~/.copier-templates/setup.py/\[\[\ _copier_conf.answers_file\ \]\].tmpl
# Changes here will be overwritten by Copier; NEVER EDIT MANUALLY
[[_copier_answers|to_nice_yaml]]
```

Inside my copier.yml I have setup my _answers_file to point to a special
file. This is because this is not a whole projet template, but one just
for a single file.

``` yaml
# copier.yml
# ...
_answers_file: .setup-py-copier-answers.yml
```

> Once I change the _answers_file I was incredibly stuck

## Run it

I'm making a library of personal copier templates in my
`~/.copier-templates` directory and I am going to run it from there.

``` bash
copier copy ~/.copier-templates/setup.py
```

## Results

After rendering the template we have the following content in our
`.setup.setup-py-copier-answers.yml` file. This will allow us to update
quick if we ever change our template.

``` yaml
# .setup-py-copier-answers.yml
# Changes here will be overwritten by Copier; NEVER EDIT MANUALLY
_src_path: /home/walkers/.copier-templates/setup.py
author_github: waylonwalker
author_name: Waylon Walker
description: awesomeness
framework: null
keywords: null
package_name: my-package
```

## Update it

This is where I was most stuck, primarily becuase `-a `
must come exactly after the base command `copier`. This felt a bit odd
to and not where I expected it so it.

``` bash
copier -a .setup-py-copier-answers.yml update
```

## Stop asking all these damn questions

So the defaults are now changed to our previous results, but it keeps
asking for them. To stop asking we can simply add a `-f` flag.

``` bash
copier -fa .setup-py-copier-answers.yml update
```