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書名： Elixir Cookbook
作者名： Paulo A Pereira
本章字?jǐn)?shù)： 480字
更新時(shí)間： 2021-07-23 20:49:38

Generating umbrella applications

The "Erlang way" is to name each self-contained unit of code as an app. Sometimes, an app may be what is referred to as a library in other languages. This is a great way to achieve code reusability and modularity, but sometimes, it is convenient to treat all the apps in a project as a single entity, committing them as a whole to version control, to allow running tests, and so on. Think of an umbrella application as a container used to hold one or more applications and to make them behave as a single application.

This recipe shows how to create umbrella applications with Mix.

How to do it…

Generate an umbrella application to contain other applications:
```
mix new --umbrella container
```
What happens next is shown in the following screenshot:

Generate application_one and application_two inside the container/apps directory:

> cd container/apps
> mix new application_one
> mix new application_two

Modify the tests in the applications as follows:
- Change the test in container/apps/application_one/application_one_test.exs like this:
```
test "the truth on application one" do
  IO.puts "Running Application One tests"
  assert 1 + 1 == 2
end
```
- Change the test in container/apps/application_two/application_two_test.exs as shown here:
```
test "the truth on application two" do
  IO.puts "Running Application Two tests"
  assert 2 - 1 == 1
end
```
Run the tests in all applications (inside the container directory):
```
> mix test
```
The result of these tests is shown here:
Now run the tests individually. Firstly, run them for application_one as follows:
```
> cd apps/application_one
> mix test
```
The outcome of these tests is shown in the following screenshot:

For application_two , run them like this:
```
> cd ../application_two
> mix test
```
The result of these tests is shown in this screenshot:

How it works…

By generating this structure of the application with subprojects under the apps directory, Elixir makes dependency management, compilation, and testing easier. It is possible to perform these tasks at the umbrella application level, affecting all the subprojects, or at each subproject level, allowing a high level of granularity.

官术网_书友最值得收藏!

Generating umbrella applications

How to do it…

How it works…

See also

官术网_书友最值得收藏!

Elixir Cookbook

Generating umbrella applications

How to do it…

How it works…

See also