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Diffstat (limited to 'guide/getting_started.md')
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1 files changed, 26 insertions, 18 deletions
diff --git a/guide/getting_started.md b/guide/getting_started.md index 8c01c7d..d366b17 100644 --- a/guide/getting_started.md +++ b/guide/getting_started.md @@ -1,21 +1,20 @@ Getting started =============== -Setting up a working Erlang application is a little more complex than -for most other languages. The reason is that Erlang is designed to -build systems and not just simple applications. - -An Erlang system is typically comprised of many different nodes, -each containing many different OTP applications, each containing -many different modules and running many different processes. -Nodes may or may not be identical depending on the nature of the -system. - -To get started though, we only need one node that contains your own -HTTP application, plus the dependencies that it needs, like Cowboy. -To create our node, we need to build what is called a release. A -release is a set of files that contain the Erlang VM plus all the -applications required to run our node. +Erlang is more than a language, it is also an operating system +for your applications. Erlang developers rarely write standalone +modules, they write libraries or applications, and then bundle +those into what is called a release. A release contains the +Erlang VM plus all applications required to run the node, so +it can be pushed to production directly. + +This chapter walks you through all the steps of setting up +Cowboy, writing your first application and generating your first +release. At the end of this chapter you should know everything +you need to push your first Cowboy application to production. + +Application skeleton +-------------------- Let's start by creating this application. We will simply call it `hello_erlang`. This application will have the following directory @@ -130,6 +129,9 @@ That's not enough however. Since we are building a Cowboy based application, we also need to initialize Cowboy when we start our application. +Setting up Cowboy +----------------- + Cowboy does nothing by default. Cowboy uses Ranch for handling the connections and provides convenience @@ -198,6 +200,9 @@ init([]) -> Finally, we need to write the code for handling incoming requests. +Handling HTTP requests +---------------------- + Cowboy features many kinds of handlers. For this simple example, we will just use the plain HTTP handler, which has three callback functions: `init/3`, `handle/2` and `terminate/3`. You can find more @@ -235,6 +240,9 @@ Its usage is documented in the The code for our application is ready, so let's build a release! +Compiling +--------- + First we need to download `erlang.mk`. ``` bash @@ -271,6 +279,9 @@ haven't made any typo when creating the previous files. $ make ``` +Generating the release +---------------------- + That's not all however, as we want to create a working release. For that purpose, we need to create a `relx.config` file. When this file exists, `erlang.mk` will automatically download `relx` @@ -299,6 +310,3 @@ $ ./_rel/bin/hello_erlang console If you then access `http://localhost:8080` using your browser, you should receive a nice greet! - -You can find many more examples in the `examples/` directory -of the Cowboy repository. |