Profiling a PHP script with XDebug

Jawira Portugal — Tue, 07 Jun 2022 20:01:07 +0000

Software profiling is a powerful technique when you want to optimize your code. Among other things, a profile snapshot will show you which parts of your software are the slower.

In this article I will explain how to create a profile snapshot for a PHP script.

Requirements

I assume you are using Ubuntu and you already have PHP installed. Please also install XDebug 3 and KCachegrind:

$ apt install php-xdebug
$ apt install kcachegrind

Create profile file

As an example, I will profile tests from jawira/plantuml-encoding.

$ git clone https://github.com/jawira/plantuml-encoding.git
$ cd plantuml-encoding
$ php tests/vanilla.php

Execute the following command to profile tests/vanilla.php:

$  php -dxdebug.mode=profile -dxdebug.output_dir=. tests/vanilla.php

After the execution is finished, a new profile snapshot will be created. This profile file has the following name pattern cachegrind.out.xxxxx (where xxxxx is a number).

XDebug can be configured in php.ini. Here we have configured XDebug on-the-fly passing php.ini configuration through the terminal.

-dxdebug.mode=profile: This option makes profile mode enabled for this command.
-dxdebug.output_dir=.: Save profile snapshots in current dir ".", otherwise snapshots are saved in /tmp.

In our case profiling mode is ephemeral, but it can be a problem if you are activating profiling by other means (for example directly editing php.ini file). Profile snapshots can take a LOT of disk space, never leave profile mode permanently enabled.

Opening profile file

To visualize your profile snapshot, simply open the snapshot (in our case cachegrind.out.14476) with KCachegrind.

The reading and interpretation of profiling files are beyond the scope of this article, yet I recommend you to see this video https://www.youtube.com/watch?v=h-0HpCblt3A presenting KCachegrind.

Conclusion

Creating a profile snapshot is easy if you understand how to configure XDebug properly. Using -d options is very convenient technique to enable profiling from the terminal.

Resources

Defining dynamic Host rule in Traefik v2

Jawira Portugal — Mon, 02 May 2022 18:44:42 +0000

Traefik is a reverse http proxy, it works specially well with docker and docker-compose environments. Traefik will receive all your incoming web requests and redirect them to Docker containers.

In order to redirect your requests, Traefik will use a router to identify the appropriate web server.

In this article I show you how I configured a default "Host rule" for my development environment. This rule will automatically add a rule for any service.

http://<service>.<project>.localhost

I assume you already have some experience with Docker and Traefik.

Traefik configuration

First install Traefik. Let's create a new project with the following structure:

traefik/
└── docker-compose.yaml

You only need one single file to start using Traefik. This is the content of traefik/docker-compose.yaml:

version: '3.7'
services:

  traefik:
    image: traefik:v2.7
    restart: always
    command:
      - '--api.insecure=true'
      - '--providers.docker.exposedByDefault=false'
      - '--providers.docker.network=traefik_default'
      - '--providers.docker.defaultRule=Host(`{{ index .Labels "com.docker.compose.service" }}.{{ index .Labels "com.docker.compose.project" }}.localhost`)'
    labels:
      - 'traefik.http.services.traefik-traefik.loadBalancer.server.port=8080'
      - 'traefik.enable=true'
    ports:
      - '80:80'
      - '8080:8080'
    volumes:
      - '/var/run/docker.sock:/var/run/docker.sock'
    networks:
      - default

networks:
  default:

This is the most important command option when creating dynamic rules:

- '--providers.docker.defaultRule=Host(`{{ index .Labels "com.docker.compose.service" }}.{{ index .Labels "com.docker.compose.project" }}.localhost`)'

Let's see what the previous line does:

--providers.docker.defaultRule: this is the rule to be used if container doesn't define one.
Host(): the requested domain will be used for routing.
{{ index .Labels "com.docker.compose.service" }}: this represents the service name, the one you define in docker-compose.yaml.
{{ index .Labels "com.docker.compose.project" }}: this placeholder will be replaced with project name. By default, the project name is the directory name, you can also specify this value with -p <project> option.
Finally .localhost is a reserved domain, it will always point to the loopback address 127.0.0.1. Using .localhost, you will not need to add your development domains to /etc/hosts.

Start Traefik with the following command:

$ docker compose -p traefik up -d

Traefik is up and running now.

Creating a sample project

We will create a demo project to check if our dynamic rules work properly. This is the structure of foo project:

foo/
└── docker-compose.yaml

We define an Apache server within foo/docker-compose.yaml:

version: "3.7"
services:

  web:
    image: httpd
    labels:
      - traefik.enable=true
    networks:
      - default
      - traefik_default

networks:
  default:
  traefik_default:
    external: true

Let's execute our demo project:

$ docker compose -p foo up -d

Now, if we open http://web.foo.localhost we will see Apache's welcome message:

Using a custom rule

We can also specify a custom rule for a service, this custom rule will override the default rule.

For example we want to use my-foo.localhost, to do so we simple add a new label:

# ...
  web:
    image: httpd
    labels:
      - traefik.enable=true
+     - traefik.http.routers.foo-project.rule=Host(`my-foo.localhost`)
# ...

To make changes take effect we have to launch again our project using docker compose -p foo up -d. This is the result:

As you can see everything works as expected.

Conclusion

Traefik is a highly configurable reverse proxy. You only need one line of code to have dynamic domains, these domains are well suited for development environments.

If you use .localhost tld, you won't need to declare your domains within /etc/hosts.

Forem: Jawira Portugal

Profiling a PHP script with XDebug

Requirements

Create profile file

Opening profile file

Conclusion

Resources

Defining dynamic Host rule in Traefik v2

Traefik configuration

Creating a sample project

Using a custom rule

Conclusion