Recently had the chance to look into the awesome book “Give and Take” by Adam Grant. Here are two good presentations on slideshare on the book summary:
Give and Take
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Author Archives: shafiulcse
PHP Conference Asia 2015 Recap
The First Pan-Asian PHP conference happened in Singapore on last 22 – 23 September, 2015. Many international and regional speakers presented their valuable speeches in the event.
Group Picture from PHPConfAsia
While in USA, EU lots of community events happens through the year, comparatively very few events happen in Asia! Now at least some people has taken the initiative to organize this great event. Heartiest thanks to Michael Cheng (@coderkungfu) and other people who worked hard to make the conference smooth & enjoyable.
It was really an awesome experience being in the conference.
At Widespace, we use PHP (specifically Laravel) for several platforms, two of us from our Dhaka office joined the event.
Events on Tuesday:
- Rasmus Lerdorf started the conference with his keynote presentation. It was mostly about upcoming PHP 7. Listening about the next PHP version from the PHP creator was really exciting. He showed some new feature coming with PHP 7, compatibility and also provided performance comparison of PHP7 with other PHP versions and HHVM for different projects. You can get the rich presentation slides here.
- After the tea break, Stéphane Boisvert came into stage with his in-depth discussion about WordPress Security. He discussed different security topics like sql injection, csrf attack, sanitization, authorization in wordpress. Thanks Stéphane for providing nice ‘WordPress’ branded Sunglasses 🙂 His talk will be very valuable for WordPress developers.
- Later came a storyteller, telling a faily tale with animation! Well, Steven Cooper described PayPal and Braintree API’s and how they can be integrated into code with the help of fairy tale. You can enjoy his fairy tale here.
- Before Lunch, the last session was about application (Magento) performance improvement by Harald Zeitlhofer from Austria. He gave an example how a magento installation performance issues were detected and corrected with the help of Dynatrace performance monitoring tool.
- First session after awesome lunch was by Jack Lenox. He has shown the way of combining React development techniques with a more traditional PHP workflow. His lecture can be found here.
- After that Bagus Aji Santoso came into stage telling about Panada Framework, Simple but High Performance PHP Framework from Indonesia. He was a bit shy, presenting for the first time in front of international audience 🙂 Panada framework seems to be popular in Indonesia powering up several popular local sites. See features about Panada in presentation here.
- Edwin Ong then gave a lightning talk about PHP streams. PHP Streams were introduced with PHP 4.3.0 as a way of generalizing file, network, data compression, and other operations which share a common set of functions and uses. He discussed how we use it knowingly or unknowingly regularly.
- Before the tea break, last talk was given by Sam Yong, a student from NUS, with topic: Go Reinvent The Wheel. It is certainly true that reinventing the wheel in software industry drives numerous innovations which we see today.
- Pierre Joye, PHP Core Developer and OSS contributor, then gave rich talk about PHP7, HHVM and Co. Besides showing performance statistics, new features about PHP 7, he also talked about Zephir and alternate PHP implementations including HHVM. See his presentation.
- Premshree Pillai explained how they built a scalable system for tracking shipping packages for Etsy. He shared their architecture in Etsy and interested audience also asked several questions about their implementation. His presentation is shared in slideshare.
- The last session of first day was with the topic ‘Why Your Test Suite Sucks’ given by Ciaran McNulty, Senior Trainer, Inviqa. He has nicely shown how to evolve from no-test to TDD state. He also showed several code snippet and how to improve the code in those cases. We should really follow the practices that Ciaran mentions in this nice presentation.
Events on day 2 will be published soon…
Performance of yield vs built-in range function
Just out of curiosity, tried to benchmark the memory used by PHP generator(yield) and range function.
Code used here:
function xrange($start, $limit, $step = 1) {
if ($start < $limit) {
if ($step <= 0) {
throw new LogicException('Step must be positive');
}
for ($i = $start; $i <= $limit; $i += $step) { yield $i; } } else { if ($step >= 0) {
throw new LogicException('Step must be negative');
}
for ($i = $start; $i >= $limit; $i += $step) {
yield $i;
}
}
}
$preMemory = memory_get_usage(true);
echo 'Before: ' . $preMemory/1024;
$total = 0;
foreach(xrange(1, 1000000) as $i) {
$total += $i;
}
echo "\nYield Took: " . (memory_get_usage(true) - (float)$preMemory)/1024;
$preMemory = memory_get_usage(true);
$total = 0;
foreach(range(1, 1000000) as $i) {
$total += $i;
}
echo "\nrange() Took: " . (memory_get_usage(true) - (float)$preMemory)/1024;
Result is (in kilobyte):
Before: 256 Yield Took: 0 range() Took: 768
Increasing the loop 10 times, makes the range() cause stack overflow!
Resolving GuestAdditions version mismatch in vagrant/homestead vm (failed to mount shared folders / modprobe vboxsf failed)
While trying to install homestead machine for Laravel, got some annoying issue: failed to mount shared folders. I had vagrant installed earlier with different version than homestead, causing the problem.
The output from ‘homestead up’ was:
$ homestead up /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/pre-rubygems.rb:31: warning: Insecure world writable dir /usr/local in PATH, mode 040777 /opt/vagrant/embedded/gems/gems/bundler-1.10.5/lib/bundler/shared_helpers.rb:78: warning: Insecure world writable dir /usr/local in PATH, mode 040777 Bringing machine 'default' up with 'virtualbox' provider... ==> default: Checking if box 'laravel/homestead' is up to date... ==> default: Clearing any previously set forwarded ports... ==> default: Clearing any previously set network interfaces... ==> default: Preparing network interfaces based on configuration... default: Adapter 1: nat default: Adapter 2: hostonly ==> default: Forwarding ports... default: 443 => 44300 (adapter 1) default: 3306 => 33060 (adapter 1) default: 5432 => 54320 (adapter 1) default: 80 => 8080 (adapter 1) default: 81 => 8181 (adapter 1) default: 86 => 8686 (adapter 1) default: 82 => 8282 (adapter 1) default: 22 => 2222 (adapter 1) ==> default: Running 'pre-boot' VM customizations... ==> default: Booting VM... ==> default: Waiting for machine to boot. This may take a few minutes... default: SSH address: 127.0.0.1:2222 default: SSH username: vagrant default: SSH auth method: private key default: Warning: Connection timeout. Retrying... ==> default: Machine booted and ready! Got different reports about installed GuestAdditions version: Virtualbox on your host claims: 5.0.4 VBoxService inside the vm claims: 4.3.6 Going on, assuming VBoxService is correct... GuestAdditions seems to be installed (4.3.6) correctly, but not running. Got different reports about installed GuestAdditions version: Virtualbox on your host claims: 5.0.4 VBoxService inside the vm claims: 4.3.6 Going on, assuming VBoxService is correct... Starting the VirtualBox Guest Additions ...fail! (modprobe vboxsf failed) Got different reports about installed GuestAdditions version: Virtualbox on your host claims: 5.0.4 VBoxService inside the vm claims: 4.3.6 Going on, assuming VBoxService is correct... Removing existing VirtualBox DKMS kernel modules ...done. Removing existing VirtualBox non-DKMS kernel modules ...done. Building the VirtualBox Guest Additions kernel modules The headers for the current running kernel were not found. If the following module compilation fails then this could be the reason. Building the main Guest Additions module ...done. Building the shared folder support module ...fail! (Look at /var/log/vboxadd-install.log to find out what went wrong) Doing non-kernel setup of the Guest Additions ...done. Restarting VM to apply changes... ==> default: Attempting graceful shutdown of VM... ==> default: Booting VM... ==> default: Waiting for machine to boot. This may take a few minutes... default: SSH address: 127.0.0.1:2222 default: SSH username: vagrant default: SSH auth method: private key default: Warning: Connection timeout. Retrying... ==> default: Machine booted and ready! ==> default: Checking for guest additions in VM... default: The guest additions on this VM do not match the installed version of default: VirtualBox! In most cases this is fine, but in rare cases it can default: prevent things such as shared folders from working properly. If you see default: shared folder errors, please make sure the guest additions within the default: virtual machine match the version of VirtualBox you have installed on default: your host and reload your VM. default: default: Guest Additions Version: 5.0.4 default: VirtualBox Version: 4.3 ==> default: Setting hostname... ==> default: Configuring and enabling network interfaces... ==> default: Mounting shared folders... default: /vagrant => /Users/shafiul/source/ws_ui_vagrant Failed to mount folders in Linux guest. This is usually because the "vboxsf" file system is not available. Please verify that the guest additions are properly installed in the guest and can work properly. The command attempted was: mount -t vboxsf -o uid=`id -u vagrant`,gid=`getent group vagrant | cut -d: -f3`, vagrant /vagrant mount -t vboxsf -o uid=`id -u vagrant`,gid=`id -g vagrant`, vagrant /vagrant The error output from the last command was: /sbin/mount.vboxsf: mounting failed with the error: No such device
Digging into the error message, found clue in below lines:
Virtualbox on your host claims: 5.0.4 VBoxService inside the vm claims: 4.3.6
So, I decided to install VBoxGuestAdditions 5.0.4 in both host and guest.
In some cases, it has been observed that only running the below command solves the problem:
$ vagrant plugin install vagrant-vbguest
and then run homestead up again.
In case, the error persists, then follow the below steps, which I had to follow to run my homestead machine.
Though the mounting of shared folder failed while starting vm, but vm started successfully. I needed to ssh into vm by homestead ssh and run the following commands inside vm to install dependencies for VBoxGuestAdditions:
$ sudo apt-get update && sudo apt-get install linux-generic $ sudo apt-get install dkms build-essential linux-headers-$(uname -r) $ sudo apt-get install binutils gcc make patch libgomp glibc-headers glibc-devel kernel-headers $ sudo apt-get install kernel-devel $ sudo apt-get install kernel-pae-devel $ sudo apt-get install virtualbox-guest-dkms $ sudo apt-get install xserver-xorg xserver-xorg-core
I am not sure if the last line was needed, please try without it, and see if you get error in next step.
Inside the vm:
$ cd /opt $ ls VBoxGuestAdditions-4.3.6 VBoxGuestAdditions-5.0.4
but the later was empty. So I needed to download and install it.
$ cd /opt/ $ sudo wget http://download.virtualbox.org/virtualbox/5.0.4/VBoxGuestAdditions_5.0.4.iso $ sudo mount VBoxGuestAdditions_5.0.4.iso -o loop /mnt $ sudo sh VBoxLinuxAdditions.run Output should be like below: Verifying archive integrity... All good. Uncompressing VirtualBox 5.0.4 Guest Additions for Linux............ VirtualBox Guest Additions installer Removing installed version 4.3.6 of VirtualBox Guest Additions... Copying additional installer modules ... Installing additional modules ... Removing existing VirtualBox DKMS kernel modules ...done. Removing existing VirtualBox non-DKMS kernel modules ...done. Building the VirtualBox Guest Additions kernel modules ...done. Doing non-kernel setup of the Guest Additions ...done. You should restart your guest to make sure the new modules are actually used $ cd /opt/ $ sudo umount /mnt $ rm -rf *.iso
In my host mac(yosemite), I had to install the new GuestAdditions
$ sudo wget http://download.virtualbox.org/virtualbox/5.0.4/VBoxGuestAdditions_5.0.4.iso $ sudo mv /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso ~/.homestead $ sudo cp VBoxGuestAdditions_5.0.4.iso /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso
You can remove VBoxGuestAdditions.iso in ~/.homestead dir.
Next step is updating the vagrant version to 5.0.4. Link to installer: http://download.virtualbox.org/virtualbox/5.0.4/VirtualBox-5.0.4-102546-OSX.dmg
And then finally homestead machine ran successfully.
Running/executing PHP from command line
Sometimes we need to check the result of small snippet of code. We can check it easily from command line. I prefer to use the following 2 options:
- PsySH: I think its the best REPL for PHP. It has tab completion, documentation and lot of other features. In its site, it says about it: A runtime developer console, interactive debugger and REPL for PHP.
- PHP Interactive mode: PHP has an interactive mode, which can be opened running by command #
php -a. Command line will show:php >. Then you can run php statements from there - Boris: tiny but useful REPL for PHP. You can find here Boris Installation Guide.
Some useful commands:
php -f filename.php-> to run php filephp -f filename.php param=value-> to run php file and send query string to script, get using $_GET[‘param’]php -m -> to get all installed modules list- php -i -> check php.ini configs. For example you can see the timezone set in config using:
php -i | grep timezone - php –rf function_name -> quickly check function information
Accidentally deleted cron jobs :( How to recover?
I don’t know exactly, why on earth crontab default key for edit(-e) and remove(-r) was designed sitting next to each other. Accidentally all cron jobs may be removed by entering -r, while trying to edit. So be careful!
How to recover:
- If you have backups, that’s great, restore from there.
- If no backup, find the cron jobs from log file using command:$
cat /var/log/cron | grep -v your_command.
- Repeatedly recover commands from log file.
Future Proof:
Always maintain a file containing all crontab entries and keep it in code repository(e.g git). Then at any time, you can get from repo and re-store in unix.
Welcome to Coding Beauty
Here there will be posts on coding related topics. Stay tuned 🙂
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