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This tutorial demonstrates how to implement a “hello world” HTTP interface using OpenResty.

screenshot 1

First of all, we make sure we are using OpenResty’s nginx.

export PATH=/usr/local/openresty/nginx/sbin:$PATH
which nginx

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It’s usually in this path.

And then we go to the home directory.

cd ~/

Create and switch to a directory named ‘hello’ for our example.

mkdir hello
cd hello

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Create the boilerplate sub-directories for the OpenResty application.

mkdir logs conf
ls

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Then let’s create a simple nginx.conf file under the ‘conf’ sub-directory. Here we use vim.

vim conf/nginx.conf
  1. Let’s enable a single nginx worker process for simplicity.
  2. We enable at most 1024 per-worker connections.
  3. And here we configure an HTTP server.
  4. Listen to the 8080 port with ‘reuseport’ enabled.
  5. Finally we add a root location to this server.
  6. We set the default MIME type to text/plain.
  7. We embed some Lua code to emit a response with the body ‘Hello World’.
worker_processes 1;

events {
    worker_connections 1024;
}

http {
    server {
        listen 8080 reuseport;

        location / {
            default_type text/plain;
            content_by_lua_block {
                ngx.say("Hello World")
            }
        }
    }
}

Now let’s test if the configuration is correct with the ‘-t’ option.

nginx -p $PWD/ -t

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Looking good!

Now let’s start this OpenResty application for real.

nginx -p $PWD/

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And check if the nginx processes are running.

ps aux|grep nginx|grep -v /tmp/

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Nice. They are up. One master and one worker.

We can now send a test HTTP request to this server with the ‘curl’ command-line utility.

curl 'http://127.0.0.1:8080/'

We’re indeed getting the response body ‘Hello World’.

screenshot 23

We can also try accessing the / URI in a web browser.

screenshot 25

As we can see, it also displays “Hello World” as expected.

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About The Author

Yichun Zhang (Github handle: agentzh), is the original creator of the OpenResty® open-source project and the CEO of OpenResty Inc..

Yichun is one of the earliest advocates and leaders of “open-source technology”. He worked at many internationally renowned tech companies, such as Cloudflare, Yahoo!. He is a pioneer of “edge computing”, “dynamic tracing” and “machine coding”, with over 22 years of programming and 16 years of open source experience. Yichun is well-known in the open-source space as the project leader of OpenResty®, adopted by more than 40 million global website domains.

OpenResty Inc., the enterprise software start-up founded by Yichun in 2017, has customers from some of the biggest companies in the world. Its flagship product, OpenResty XRay, is a non-invasive profiling and troubleshooting tool that significantly enhances and utilizes dynamic tracing technology. And its OpenResty Edge product is a powerful distributed traffic management and private CDN software product.

As an avid open-source contributor, Yichun has contributed more than a million lines of code to numerous open-source projects, including Linux kernel, Nginx, LuaJIT, GDB, SystemTap, LLVM, Perl, etc. He has also authored more than 60 open-source software libraries.