<!-- menu -->

- [Introducing NGINX Unit](#introducing-nginx-unit)
- [System Requirements for Running Unit](#system-requirements-for-running-unit)
- [Downloading Unit Binaries](#downloading-unit-binaries)
  - [Downloading the Unit Package on CentOS Systems](#downloading-the-unit-package-on-centos-systems)
  - [Downloading the Unit Package on Ubuntu Systems](#downloading-the-unit-package-on-ubuntu-systems)
- [Compiling Unit from Source](#compiling-unit-from-source)
  - [Downloading the Unit Source Code](#downloading-the-unit-source-code)
    - [Downloading the Source from the Mercurial Repository](#downloading-the-source-from-mercurial-repository)
    - [Downloading the Source from the GitHub Repository](#downloading-the-source-from-git-repository)
    - [Downloading the Source as a Tarball](#downloading-the-source-as-a-tarball)
  - [Installing Required Software on Ubuntu Systems](#installing-required-software-on-ubuntu-systems)
  - [Installing Required Software on CentOS Systems](#installing-required-software-on-centos-systems)
  - [Configuring the Unit Source](#configuring-the-unit-source)
    - [Configuring the Unit Source for Go](#configuring-the-unit-source-for-go)
    - [Building the Go Application for Unit](#building-the-go-applications-for-unit)
    - [Configuring the Unit Source for PHP](#configuring-the-unit-source-for-php)
    - [Configuring the Unit Source for Python](#configuring-the-unit-source-for-python)
  - [Compiling Unit](#compiling-unit)
- [Installing Unit From Source](#installing-unit-from-source)
- [Starting and Stopping Unit](#starting-and-stopping-unit)
- [Configuring Unit with the JSON API](#configuring-unit-with-the-json-api)
  - [Configuring Application Objects](#configuring-application-objects)
  - [Configuring Listener Objects](#configuring-listener-objects)
  - [Minimum Configuration](#minimum-configuration)
  - [Creating Configuration Objects](#creating-configuration-objects)
    - [Example: Create a Full Configuration](#example-create-a-full-configuration)
    - [Example: Create an Application Object](#example-create-an-application-object)
  - [Displaying Configuration Objects](#displaying-configuration-objects)
    - [Example: Display the Full Configuration](#example-display-the-full-configuration)
    - [Example: Display One Object](#example-display-one-object)
  - [Modifying Configuration Objects](#modifying-configuration-objects)
    - [Example: Change the Application for a Listener](#example-change-the-application-for-a-listener)
    - [Example: Change the File Path for an Application](#example-change-the-file-path-for-an-application)
  - [Deleting Configuration Objects](#deleting-configuration-objects)
    - [Example: Delete a Listener](#example-delete-a-listener)
  - [JSON Specification for Listener and Application Objects](#json-specification-for-listener-and-application-objects)
    - [Listener](#listener)
    - [Go Application](#go-application)
    - [PHP Application](#php-application)
    - [Python Application](#python-application)
    - [Full Example](#full-example)
- [License and Contributing Changes](#license-and-contributing-changes)
- [Troubleshooting](#troubleshooting)

<!-- /menu -->

<!-- section:1 -->

## Introducing NGINX Unit

NGINX Unit is a dynamic web application server, designed to run applications
in multiple languages. Unit is lightweight, polyglot, and dynamically
configured via API. The design of the server allows reconfiguration of
specific application parameters as needed by the engineering or operations.

NGINX Unit is currently available as a beta. As such, it is suitable for use
in a testing environment, but is not recommended for use in production.

<!-- /section:1 -->

<!-- section:2 -->

## System Requirements for Running Unit

NGINX Unit is tested to compile and run on the following systems:
   * Linux 2.6 or later
   * FreeBSD 9 or later
   * MacOS X
   * Solaris 11

Architectures:
   * i386
   * amd64
   * powerpc
   * arm

For applications running in NGINX Unit you need the respective programming
languages:
   * Python 2.6, 2.7, 3
   * PHP 5, 7
   * Go 1.6 or later

You can run multiple versions of the same language installed on the same
system.

<!-- /section:2 -->

<!-- section:3 -->

## Downloading Unit Binaries

Precompiled binaries for Unit are available for CentOS&nbsp;7.0 and
Ubuntu&nbsp;16.04&nbsp;LTS.

### Downloading the Unit Package on CentOS Systems

   1. Create the file **/etc/yum.repos.d/unit.repo** with the following
   contents:

   ```
   [unit]
   name=unit repo
   baseurl=http://nginx.org/packages/centos/7/$basearch/
   gpgcheck=0
   enabled=1
   ```

   2. Download the Unit package:

   ```
   # apt-get update
   # apt-get install unit
   ```

### Downloading the Unit Package on Ubuntu Systems

   1. Download the [key](http://nginx.org/keys/nginx_signing.key) used to sign
   the NGINX,&nbsp;Inc. repository and packages.

   2. Add the key to the `apt` program's keyring. The program can then
   authenticate the NGINX repository signature, which eliminates warnings
   about a missing PGP key during installation of the Unit package.

   ```
   # sudo apt-key add nginx_signing.key
   ```

   3. Append the following to the end of the file **/etc/apt/sources.list**:

   ```
   deb http://nginx.org/packages/ubuntu/ xenial unit
   deb-src http://nginx.org/packages/ubuntu/ xenial unit
   ```

   4. Download the Unit package:

   ```
   # apt-get update
   # apt-get install unit
   ```

<!-- /section:3 -->

<!-- section:4 -->

## Compiling Unit from Source

This section explains how to compile and install Unit from the source code.

### Downloading the Unit Source Code

There are three ways to obtain the Unit source code: from the NGINX,&nbsp;Inc.
Mercurial repository, from GitHub, or in a tarball.

In each case, the sources are placed in the **unit** subdirectory of the
current working directory.

#### Downloading the Source from the Mercurial Repository

   1. If don't already have the Mercurial software, download and install it.
   For example, on Ubuntu systems, run this command:

   ```
   # apt-get mercurial
   ```

   2. Download the Unit sources:

   ```
   # hg clone hg.nginx.org/unit
   ```

#### Downloading the Source from the GitHub Repository

   1. If don't already have the Git software, download it. See the [GitHub
   documentation](https://help.github.com/).

   2. Download the Unit sources:

   ```
   # git clone https://github.com/nginx/unit
   ```

#### Downloading the Source as a Tarball

**TBD**

### Installing Required Software on Ubuntu Systems

Before configuring and compiling Unit on Ubuntu systems, you must install the
required build tools plus the library files for each of the available
languages (Go, PHP, and Python) that you want to support.

   1. Install the build tools. Note that they might require more than
   100&nbsp;MB of disk space.

   ```
   # apt-get install build-essential
   ...
   Need to get 39.0 MB of archives.
   After this operation, 139 MB of additional disk space will be used.
   Do you want to continue? [Y/n] Y
   ...
   ```

   2. If you are supporting Go, install the `golang` package. The required
   additional disk space might be about 200&nbsp;MB.

   ```
   # apt-get install golang
   ...
   Need to get 29.0 MB of archives.
   After this operation, 198 MB of additional disk space will be used.
   Do you want to continue? [Y/n] Y
   ...
   ```

   3. If you are supporting PHP, install the `php-dev` and `libphp-embed`
   packages. The required additional disk space might be around 20&nbsp;MB.

   ```
   # apt-get install php-dev
   ...
   Need to get 5,230 kB of archives.
   After this operation, 20.6 MB of additional disk space will be used.
   Do you want to continue? [Y/n] Y
   ...

   # apt-get install libphp-embed
   ...
   Need to get 1,230 kB of archives.
   After this operation, 4,330 kB of additional disk space will be used.
   Do you want to continue? [Y/n] Y
   ...
   ```

   4. If you are supporting Python, install the `python-dev` package. The
   required additional disk space might be around 60&nbsp;MB.

   ```
   # apt-get install python-dev
   ...
   1 upgraded, 13 newly installed, 0 to remove and 151 not upgraded.
   Need to get 33.3 MB of archives.
   After this operation, 62.3 MB of additional disk space will be used.
   Do you want to continue? [Y/n] Y
   ...
   ```

### Installing Required Software on CentOS Systems

Before configuring and compiling Unit on CentOS systems, you must install the
required build tools plus the library files for each of the available
languages (Go, PHP, and Python) that you want to support.

   1. Install the build tools. Note that they might require more than
   40&nbsp;MB of disk space.

   ```
   # yum install gcc make
   ...
   Total download size: 18 M
   Installed size: 42 M
   Is this ok [y/d/N]: y
   ...
   ```

   2. If you are supporting Go, install the `golang` package. The required
   additional disk space might be about 230&nbsp;MB.

   ```
   # yum install golang
   ...
   Total download size: 44 M
   Installed size: 231 M
   Is this ok [y/d/N]: y
   ...
   ```

   3. If you are supporting PHP, install the `php-devel` and `php-embedded`
   packages. The required additional disk space might be around 20&nbsp;MB.

   ```
   # yum install php-devel php-embedded
   ...
   Total download size: 5.2 M
   Installed size: 21 M
   Is this ok [y/d/N]: y
   ...
   ```

   4. If you are supporting Python, install the `python-devel` package. The
   required additional disk space might be around 1&nbsp;MB.

   ```
   # yum install python-devel
   ...
   Total download size: 393 k
   Installed size: 1.0 M
   Is this ok [y/d/N]: y
   ...
   ```

### Configuring the Unit Source

With Unit, you can simultaneously run applications that use different versions
of a supported language (Go, PHP, or Python). You need to configure a separate
Unit module for each one. The following commands create the necessary
instructions in the **Makefile** for each module.

#### Configuring the Unit Source for Go

NGINX Unit will provide the Go package that is required for running your Go
application inside Unit.

   1. Set the `GOPATH` environment variable, which sets the output directory
   for the Unit Go package.

   ```
   # export GOPATH=/home/user/go_apps
   ```

   2. Run the following command:

   ```
   # ./configure go
   configuring Go package
   checking for Go ... found
    + go version go1.6.2 linux/amd64
    + Go package path: "/home/user/go_apps"
    ```

#### Building the Go Application for Unit

   1. Modify the source file for the Go application, making changes in two
   places:

       a. In the `import` section, add `"unit"` on a separate line.

      ```
      import {
          "fmt"
          "net/http"
          "unit"
      }
      ```

       b. In the `main()` function, comment out the `http.ListenandServe`
       function and insert the `unit.ListenAndServe` function.

      ```
      func main() {
           http.HandleFunc("/", handler)
           //http.ListenAndServe(":8080", nil)
           unit.ListenAndServe(":8080", nil)
      ```

   2. Build the Go application.

      ```
      # go build
      ```

If the Go application is executed directly, the unit module will fall back to
the http module. If the Go application is launched by Unit, it will communicate
with the Unit router via shared memory.

#### Configuring the Unit Source for PHP

To configure a Unit module (called **php.unit.so**) for the most recent version
of PHP that the `configure` script finds bundled with the operating system, run
this command:

```
# ./configure php
```

To configure Unit modules for other versions of PHP (including versions you
have customized), repeat the following command for each one:

```
# ./configure php --module=<prefix> --config=<script-name> --lib-path=<pathname>
```

where

   * `--module` sets the filename prefix for the Unit module specific to the
   PHP version (that is, the resulting module is called
   &lt;_prefix_&gt;.**unit.so**).

   * `--config` specifies the filename of the **php-config** script for the
   particular version of PHP.

   * `--lib-path` specifies the directory for the PHP library file to use.

For example, this command generates a module called **php70.unit.so** for
PHP&nbsp;7.0:

```
# ./configure php --module=php70  \
                  --config=/usr/lib64/php7.0/php-config  \
                  --lib-path=/usr/lib64/php7.0/lib64
configuring PHP module
checking for PHP ... found
 + PHP version: 7.0.22-0ubuntu0.16.04.1
 + PHP SAPI: [apache2handler embed cgi cli fpm]
checking for PHP embed SAPI ... found
 + PHP module: php70.unit.so
 ```

#### Configuring the Unit Source for Python

To configure a Unit module (called **python.unit.so**) for the most recent
version of Python that the `configure` script finds bundled with the operating
system, run this command.

```
# ./configure python
```

To configure Unit modules for other versions of Python (including versions you
have customized), repeat the following command for each one:

```
# ./configure python --module=<prefix> --config=<script-name>
```

where

   * `--module` sets the filename prefix for the Unit module specific to the
   Python version (that is, the resulting modules is called
   &lt;_prefix_&gt;.**unit.so**).

   * `--config` specifies the filename of the **python-config** script for the
   particular version of Python.

For example, this command generates a module called **py33.unit.so** for
Python&nbsp;3.3:

```
# ./configure php --module=py33  \
                  --config=python-config-3.3
configuring Python module
checking for Python ... found
checking for Python version ... 3.3
 + Python module: py33.unit.so
```

### Compiling Unit

To compile the Unit executable and all configured modules for PHP, Python, or
both, run this command:

```
# make all
```

To compile the packages for Go:

   1. Verify that the `GOPATH` environment variable is set correctly, or set
   the `GOPATH` variable.

   ```
   # go env GOPATH

   # export GOPATH=<path>
   ```

   2. Compile the packages:

   ```
   # make go
   ```

<!-- /section:4 -->

<!-- section:5 -->

## Installing Unit From Source

To install Unit with all modules and Go packages, run the following command:

```
# make install
```

<!-- /section:5 -->

<!-- section:6 -->

## Starting and Stopping Unit

To start the Unit daemon, run this command:

```
# unitd
```

<!-- /section:6 -->

<!-- section:7 -->

## Configuring Unit with the JSON API

By default, the Unit API is available in the control socket file
**unit.control.sock**.

### Configuring Application Objects

For each application, you use the API to define a JSON object in the
`applications` section of the Unit configuration. The JSON object defines
several characteristics of the application, including the language it's written
in, the number of application worker processes to run, the directory with
the file or files for the application, and parameters that vary by language.

This example runs three workers of the PHP application named **blogs** using the
files found in the **/www/blogs/scripts** directory. The default launch file
when the URL doesn't specify the PHP file is **index.php**.

   ```
   {
        ...
        "applications": {
            "blogs": {
                "type": "php",
                "workers": 20,
                "root": "/www/blogs/scripts",
                "index": "index.php"
            }
        }
   }
   ```

### Configuring Listener Objects

For an application to be accessible via HTTP, you must define at least
one listener for it in the `listeners` section of the Unit configuration. A
listener is an IP address and port on which Unit listens for client requests to
a named application. The IP address can be either a full address (for example,
`127.0.0.1:8300`) or a wildcard (for example, ``*:8300`).

In this example, requests received on port&nbsp;8300 are sent to the **blogs**
application:

    ```
    {
         "listeners": {
             "*:8300": {
                 "application": "blogs"
             }
         },
         ...
    }
    ```


For complete details about the JSON objects for each language, see
[JSON Specification for Listener and Application Objects](#json-specification-for-listener-and-application-objects).

### Minimum Configuration

The configuration must include at least one listener and associated
application, as in this example:

```
{
     "listeners": {
         "*:8300": {
             "application": "blogs"
         }
     },
     "applications": {
         "blogs": {
             "type": "php",
              "workers": 20,
              "root": "/www/blogs/scripts",
              "index": "index.php"
         }
     }
}
```

### Creating Configuration Objects

To create a configuration object, specify the JSON data for it in the body of
a `PUT` request. To reduce errors, it makes sense to write the JSON data in a
file and specify the file path with the `-d` option to the `curl` command.

#### Example: Create a Full Configuration

Create an initial configuration by uploading the contents of the **start.json**
file:

```
# curl -X PUT -d @/path/start.json  \
       --unix-socket ./control.unit.sock http://localhost:/

# curl -X PUT -d @start.json  \
       --unix-socket ./control.unit.sock http://localhost:/
```

#### Example: Create an Application Object

Create a new application object called **wiki** from the file **wiki.json**.

```
# curl -X PUT -d @wiki.json  \
       --unix-socket ./control.unit.sock http://localhost:/
```

The contents of **wiki.json** are:

```
"wiki": {
    "type": "python",
    "workers": 10,
    "module": "wsgi",
    "user": "www-wiki",
    "group": "www-wiki",
    "path": "/www/wiki"
}
```

### Displaying Configuration Objects

To display a configuration object, append its path to the `curl` URL.

#### Example: Display the Full Configuration

Display the complete configuration:

```
# curl --unix-socket ./control.unit.sock http://localhost:/
{
    "applications": {
       "blogs": {
          "type": "php",
          "user": "nobody",
          "group": "nobody",
          "workers": 20,
          "root": "/www/blogs/scripts",
          "index": "index.php"
       },

       "wiki": {
          "type": "python",
          "user": "nobody",
          "group": "nobody",
          "workers": 10,
          "path": "/www/wiki",
          "module": "wsgi"
       }
    },


   "listeners": {
      "*:8300": {
         "application": "blogs"
      },


      "*:8400": {
         "application": "wiki"
      }
   }
}
```

#### Example: Display One Object

Display the data for the **wiki** application:

```
# curl --unix-socket ./control.unit.sock http://localhost:/applications/wiki
{
    "type": "python",
    "workers": 10,
    "module": "wsgi",
    "user": "www",
    "group": "www",
    "path": "/www/wiki"
}
```

### Modifying Configuration Objects

To change a configuration object, use the `-d` option to the `curl` command to
specify the object's JSON data in the body of a `PUT` request.

#### Example: Change the Application for a Listener

Change the `application` object to **wiki-dev** for the listener on *:8400:

```
# curl -X PUT -d '"wiki-dev"' --unix-socket ./control.unit.sock  \
       'http://localhost:/listeners/*:8400/application'
{
    "success": "Reconfiguration done."
}
```

#### Example: Change the File Path for an Application

Change the `root` object for the **blogs** application to
**/www/blogs-dev/scripts**:

```
# curl -X PUT -d '"/www/blogs-dev/scripts"'  \
       --unix-socket ./control.unit.sock  \
       http://localhost:/applications/blogs/root
{
    "success": "Reconfiguration done."
}
```

### Deleting Configuration Objects

To delete a configuration object, make a `DELETE` request and append the
object's path to the `curl` URL.

#### Example: Delete a Listener

Delete the listener on *:8400:

```
# curl -X DELETE --unix-socket ./control.unit.sock  \
       'http://localhost:/listeners/*:8400'
{
    "success": "Reconfiguration done."
}
```

### JSON Specification for Listener and Application Objects

#### Listener

|  Object | Description |
| --- | --- |
| `<IP-address>:<port>`          | IP address and port on which Unit listens for requests to the named application. The IP address can be either a full address (`127.0.0.1:8300`) or a wildcard (`*:8300`).
| `application`                  | Application name.

Example:

```
"*:8300": {
           "application": "blogs"
          }
```

#### Go Application

|  Object | Description |
| --- | --- |
| `type`| Type of the application (`go`).
| `workers`           | Number of application workers.
| `executable`        | Full path to compiled Go app.
| `user` (optional)   | Username that runs the app process. <br/><br/>If not specified, `nobody` is used.
| `group` (optional)  | Group name that runs the app process. <br/><br/> If not specified, user's primary group is used.

Example:

```
"go_chat_app": {
            "type": "go",
            "executable": "/www/chat/bin/chat_app",
            "user": "www-go",
            "group": "www-go"
        }
```

#### PHP Application

|  Object | Description |
| --- | --- |
| `type`| Type of the application (`php`).
| `workers`           | Number of application workers.
| `root`              | Directory to search for PHP files.
| `index`             | Default launch file when the PHP file name is not specified in the URL.
| `script` (optional) | File that Unit runs for every URL, instead of searching for a file in the filesystem. The location is relative to the root.
| `user` (optional)   | Username that runs the app process. <br/><br/>If not specified, `nobody` is used.
| `group` (optional)  | Group name that runs the app process. <br/><br/> If not specified, user's primary group is used.

Example:

```
"blogs": {
            "type": "php",
            "workers": 20,
            "root": "/www/blogs/scripts",
            "index": "index.php",
            "user": "www-blogs",
            "group": "www-blogs"
        },
```

#### Python Application

|  Object | Description |
| --- | --- |
| `type`| Type of the application (`python`).
| `workers`           | Number of application workers.
| `path`             | Path to search for the **wsgi.py** file.
| `module`             | Required. Currently the only supported value is `wsgi`.
| `user` (optional)   | Username that runs the app process. <br/><br/>If not specified, `nobody` is used.
| `group` (optional)  | Group name that runs the app process. <br/><br/> If not specified, user's primary group is used.

Example:

```
"shopping_cart": {
             "type": "python",
             "workers": 10,
             "path": "/www/store/cart",
             "module": "wsgi",
             "user": "www",
             "group": "www"
            },
```

#### Full Example

```
{
    "listeners": {
        "*:8300": {
            "application": "blogs"
        },
        "*:8400": {
            "application": "wiki"
        },
        "*:8401": {
            "application": "shopping_cart"
        },
        "*:8500": {
            "application": "go_chat_app"
        }
    },
    "applications": {
        "blogs": {
            "type": "php",
            "workers": 20,
            "root": "/www/blogs/scripts",
            "user": "www-blogs",
            "group": "www-blogs",
            "index": "index.php"
        },
        "wiki": {
            "type": "python",
            "workers": 10,
            "user": "www-wiki",
            "group": "www-wiki",
            "path": "/www/wiki"
        },
        "shopping_cart": {
            "type": "python",
            "workers": 10,
            "module": "wsgi",
            "user": "www",
            "group": "www",
            "path": "/www/store/cart"
        },
        "go_chat_app": {
            "type": "go",
            "user": "www-chat",
            "group": "www-chat",
            "executable": "/www/chat/bin/chat_app"
        }
    }
}
```

<!-- /section:7 -->

<!-- section:8 -->

## License and Contributing Changes

NGINX Unit is released under the Apache 2.0 license.

To contribute changes, either submit them by email to <unit@nginx.org> or
submit a pull request in the https://github.com/nginx/unit repository.

<!-- /section:8 -->

<!-- section:9 -->

## Troubleshooting

**TBD**

<!-- /section:9 -->