Vianney FAIVRE

curl - How to get time spent details

2024-06-12T00:00:00+00:00

Here is how you can get some metrics when making a http request:

time spent establishing the http connection
time spent by the server (TTFB: Time to First Byte)

curl \
  --verbose  \
  --location  \
  --output /dev/null  \
  --silent  \
  --write-out 'Establish Connection: %{time_connect}s\nTTFB: %{time_starttransfer}s\nTotal: %{time_total}s\n'  \
  'https://vianneyfaivre.com'

That command will print out some tech details like what was required to establish the http connection or the size of the http response.

Timings will be printed out:

Establish Connection: 0.036697s
TTFB: 0.091912s
Total: 0.094491s

dig - How to get DNS config of a hostname

2024-06-12T00:00:00+00:00

Here is how you can see the IP Addresses that are assigned to a given hostname:

dig +short vianneyfaivre.com

Results:

199.110.153
199.109.153
199.108.153
199.111.153

Java - How to parse milliseconds

2024-01-23T00:00:00+00:00

Here is how you can parse milliseconds of a date-time with java.

public static void main(String[] args) {

    var pattern = "yyyy-MM-dd'T'HH:mm:ss[.SSS][.SS][.S]";
    var formatter = DateTimeFormatter.ofPattern(pattern);

    var dateWith0S = formatter.parse("2024-01-21T16:42:33");
    var dateWith1S = formatter.parse("2024-01-22T16:42:33.1");
    var dateWith2S = formatter.parse("2024-01-23T16:42:33.12");
    var dateWith3S = formatter.parse("2024-01-24T16:42:33.123");

    System.out.println(dateWith0S);
    System.out.println(dateWith1S);
    System.out.println(dateWith2S);
    System.out.println(dateWith3S);
}

TypeScript - tsconfig.json base files

2023-12-23T00:00:00+00:00

This github repository lists some basic config tsconfig.json files: Github - tsconfig

Spring - How to connect to RabbitMQ

2023-02-07T00:00:00+00:00

Here is a snippet to test the connectivity between your machine and a RabbitMQ instance.

public static void main(String[] args) {

    String queueName = "YOUR QUEUE";

    ConnectionFactory factory = new ConnectionFactory();
    factory.setUsername("YOUR USERNAME");
    factory.setPassword("YOUR PASSWORD");
    factory.setVirtualHost("/");
    factory.setHost("your-rabbit-host.com");
    factory.setPort(5672);

    try (Connection conn = factory.newConnection()) {
        Channel channel = conn.createChannel();

        AMQP.Queue.DeclareOk response = channel.queueDeclarePassive(queueName);
        int msgCount = response.getMessageCount();
        int consumerCount = response.getConsumerCount();

        System.out.println("msg="+msgCount+" consumers="+consumerCount);
    } catch (Exception e) {
        System.err.println(e.getMessage());
        e.printStackTrace();
    }
}

Tested with Spring Boot 2 and spring-rabbit version 1.7.4.RELEASE

How to test if a port is open

2022-12-17T00:00:00+00:00

You can use netcat aka nc to test if a port is open or not.

// Test on port 80 (open)
> nc vianneyfaivre.com 80 -v      
Connection to vianneyfaivre.com port 80 [tcp/http] succeeded!

// Test on port 81 (closed)
> nc vianneyfaivre.com 81 -v    
nc: connectx to vianneyfaivre.com port 81 (tcp) failed: Operation timed out

// Test on port 443 (open)
> nc vianneyfaivre.com 443 -v   
Connection to vianneyfaivre.com port 443 [tcp/https] succeeded!

// Bonus: get TLS info and certificates (if applicable)
> openssl s_client -connect vianneyfaivre.com:443

Spring - @Scheduled - How to get CRON next executions

2022-09-02T00:00:00+00:00

Here is a simple snippet that let you know the next time your @Scheduled annotated method will run.

// Sample for a @Scheduled(cron = "0 59 23 * * 7")

// seconds minutes hours day-of-month months day-of-week
String cronExpr = "0 59 23 * * 7";

CronSequenceGenerator cronTrigger = new CronSequenceGenerator(cronExpr);
Date exec1 = cronTrigger.next(new Date());
Date exec2 = cronTrigger.next(exec1);

System.out.println("Next execution: " + exec1);
System.out.println("Next execution: " + exec2);

Tested with Spring Boot 2.2.13.RELEASE (Quartz version: 2.3.2)

Spring Boot x Spring Cloud - Compatibility Grid

2022-05-14T00:00:00+00:00

To know which version of Spring Cloud you should use with your version of Spring Boot, you can check this compatibility grid:

"spring-cloud": {
      "Hoxton.SR12": "Spring Boot >=2.2.0.RELEASE and <2.4.0.M1",
      "2020.0.5": "Spring Boot >=2.4.0.M1 and <2.6.0-M1",
      "2021.0.0-M1": "Spring Boot >=2.6.0-M1 and <2.6.0-M3",
      "2021.0.0-M3": "Spring Boot >=2.6.0-M3 and <2.6.0-RC1",
      "2021.0.0-RC1": "Spring Boot >=2.6.0-RC1 and <2.6.1",
      "2021.0.2": "Spring Boot >=2.6.1 and <2.6.8-SNAPSHOT",
      "2021.0.3-SNAPSHOT": "Spring Boot >=2.6.8-SNAPSHOT and <3.0.0-M1",
      "2022.0.0-M1": "Spring Boot >=3.0.0-M1 and <3.0.0-M2",
      "2022.0.0-M2": "Spring Boot >=3.0.0-M2 and <3.1.0-M1"
}

Extracted from here in May 2022.

Ubuntu - How to enable touchpad vertical & horizontal scrolling

2021-08-09T00:00:00+00:00

Sometimes my pc freezes and when rebooting I can’t scroll via my touchpad anymore.

When going to the mouse settings it’s not showing the touchpad specific config as well.

That can be fixed by reconfiguring the touchpad input via its config file.

sudo gedit /usr/share/X11/xorg.conf.d/40-libinput.conf
find the Touchpad section
Add:
- Option "VerticalScrolling" "True"
- Option "HorizontalScrolling" "True"

You should end up with something like:

Section "InputClass"
    Identifier "libinput touchpad catchall"
    MatchIsTouchpad "on"
    MatchDevicePath "/dev/input/event*"
    Driver "libinput"
    Option "HorizontalScrolling" "True"
    Option "VerticalScrolling" "True"
EndSection

(This bugfix assumes you have libinput-tools installed)

Tested on Ubuntu 20.04 LTS

Spring Boot + Hibernate: how to log SQL Query and Parameters

2021-05-17T00:00:00+00:00

Here is how to enable SQL query logging (query + parameters) with Spring Boot + Hibernate.

spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.springframework.transaction=TRACE
logging.level.org.hibernate.type.descriptor.sql=TRACE

Tested with Spring Boot 2.4.4 (Hibernate version: 5.4.29.Final)