Running PHP Applications

edit this page

Running PHP Applications

Running PHP Applications¶

When running PHP applications, edit the main config file to set the type property to php and select the PHP version to use:

# .symfony.cloud.yaml

# supported versions: 7.3, 7.4
# security-fix only versions: 7.2
# deprecated versions: 5.4, 5.5, 5.6, 7.0, 7.1
type: "php:7.4"

PHP code is executed using PHP-FPM and, as of PHP 7.1, SymfonyCloud uses the Zend Thread Safe (ZTS) version of PHP.

PHP Extensions¶

PHP extensions can be enabled/disabled under the runtime.extensions and runtime.disabled_extensions sections of the main config file:

# .symfony.cloud.yaml
runtime:
    extensions:
        - http
        - redis
        - ssh2
    disabled_extensions:
        - sqlite3

Default PHP Extensions¶

The following extensions are enabled by default:

bcmath
bz2 (not in 7.0)
calendar
ctype
curl
date
dba
dom
ereg (5.6 and earlier)
exif
fileinfo
filter
ftp
gd
gettext
hash
iconv
intl
json
libxml
mbstring
mcrypt (5.6 and earlier)
mhash (5.6 and earlier)
mysql (5.6 and earlier)
mysqli
mysqlnd
openssl
pcntl
pcre
pdo
pdo_mysql
pdo_sqlite
phar
posix
session
shmop (5.6 and earlier)
simplexml
soap
sockets
sqlite3
sysvmsg
sysvsem
sysvshm
tokenizer
wddx (5.6 and earlier)
xml
xmlreader
xmlwriter
zendopcache (5.4 only) / opcache (5.5 and later)
zip
zlib

Available PHP Extensions¶

This is the complete list of extensions supported by SymfonyCloud and the PHP versions where they can be enabled:

Extension	5.4	5.5	5.6	7.0	7.1	7.2	7.3	7.4
amqp
apc
apcu
apcu_bc
applepay
bcmath
blackfire
bz2
calendar
ctype
curl
dba
dom
enchant
event
exif
ffi
fileinfo
ftp
gd
gearman
geoip
gettext
gmp
http
iconv
igbinary
imagick
imap
interbase
intl
ioncube
json
ldap
mailparse
mbstring
mcrypt
memcache
memcached
mongo
mongodb
msgpack
mssql
mysql
mysqli
mysqlnd
newrelic
oauth
odbc
opcache
pdo
pdo_dblib
pdo_firebird
pdo_mysql
pdo_odbc
pdo_pgsql
pdo_sqlite
pdo_sqlsrv
pecl-http
pgsql
phar
pinba
posix
propro
pspell
pthreads
raphf
readline
recode
redis
shmop
simplexml
snmp
soap
sockets
sodium
sourceguardian
spplus
sqlite3
sqlsrv
ssh2
sysvmsg
sysvsem
sysvshm
tideways
tideways_xhprof
tidy
tokenizer
uuid
wddx
xcache
xdebug
xhprof
xml
xmlreader
xmlrpc
xmlwriter
xsl
yaml
zbarcode
zendopcache
zip

Note

Get the up-to-date complete list of extensions running this command after you SSH into your environment: ls /etc/php/*/mods-available (for PHP 5 run ls /etc/php5/mods-available).

Warning

Starting from PHP 7.4, the redis PECL extension is not longer included because this library had several API breaks. Instead, we recommend to use the php-ext-install script to install the exact version your application must use.

Custom PHP Extensions¶

You can also use a not-listed PHP extension by following these steps:

Download the .so file for the extension as part of your build hook using curl or similar.

Note

Alternatively, if the file is not publicly downloadable, you can also build the extension in your build section (although this means rebuilding the same extension on every deployment) or add the file to your Git repository (although committing large binary blobs to Git is generally not recommended).
Edit your php.ini file in the application root (as a sibling of your .symfony.cloud.yaml file) that loads the extension using its absolute path:
1 2
; php.ini extension=/app/myextension.so

Alternate Start Command¶

Although PHP runs using PHP-FPM by default, you can also start alternative processes if desired, such as if you’re running an Async PHP daemon, a thread-based worker process, etc. To do so, define an alternative start command in the main config file:

# .symfony.cloud.yaml
web:
    commands:
        start: 'php run.php'
    upstream:
        socket_family: tcp
        protocol: http

The above configuration will execute the run.php script in the application root when the container starts, but will not launch PHP-FPM. It will also tell the front-controller (Nginx) to connect to your application via a TCP socket, which will be specified in the PORT environment variable. Note that the start command must run in the foreground.

Note

Note that PHP-FPM cannot run simultaneously along with another persistent process (such as ReactPHP or Amp). If you need both they will have to run in separate containers.

PHP Worker Sizing Hints¶

The number of workers of a PHP runtime is set automatically and can be checked by running the following command:

$ symfony ssh -- find /etc/php -name php-fpm.conf -exec grep -e '^pm.max_children' {} \;
pm.max_children = 2

SymfonyCloud uses the following formula to calculate the number of workers:

              / Container Memory - Reserved Request Memory     \
workers = max|  ------------------------------------------- , 2 |
              \           Average Request Memory               /

Container Memory: The total memory available for the container, which depends on the size of the container.
Average Request Memory: The memory that an average request is expected to require. Default value: 45 MB.
Reserved Request Memory: The memory that should be reserved for things that are not specific to a request (memory for nginx, the op-code cache, some OS page cache, etc.) Default value: 70 MB.

You can tweak the default values if your application will typically consume more memory or if your application container is swapping a lot. To do so, set the following options in the main config file:

# .symfony.cloud.yaml
runtime:
    sizing_hints:
        # values are considered megabytes
        request_memory: 10
        reserved_memory: 70

The request_memory value must be 1 MB or higher and the reserved_memory value must be 70 MB or higher.

Measuring PHP Worker Memory Usage¶

To see how much memory your PHP worker processes are using, look at the PHP access log:

1	$ symfony log php.access

In the fifth column, you’ll see the peak memory usage that occurred while each request was handled. A good way to determine an optimal request memory is with the following command:

$ tail -n5000 /var/log/php.access.log | awk '{print $6}' | sort -n | uniq -c

This will print out a table of how many requests used how much memory, in KB, for the last 5,000 requests that reached PHP-FPM (increase that number if your site has lot of traffic). As an example, consider the following output:

This indicates that the majority of requests (4800) used 2048 KB of memory. In this case that’s likely application caching at work. Most requests used up to around 10 MB of memory, while a few used as much as 18 MB and a very few (6 requests) peaked at 131 MB.

A conservative approach would suggest an average request memory of 16 MB should be sufficient. A more aggressive stance would suggest 10 MB. The more aggressive approach would potentially allow for more concurrent requests at the risk of some requests needing to use swap memory, thus slowing them down.

Note

If you are running PHP 5.x then don’t bother adjusting the worker memory usage until you upgrade to PHP 7.x. PHP 7 is way more memory efficient and you will likely need less than half as much memory per process with PHP7.

PHP Configuration¶

There are three ways to customize php.ini values for your application.

Option 1. Create a file called php.ini in the root directory of the application. This is the recommended method:

; php.ini
memory_limit = 256M

Option 2. Use the variables.php property of the main config file:

# .symfony.cloud.yaml
variables:
    php:
        memory_limit: 256M

Option 3. Define the values as env vars for some specific environment. This method is mostly useful on development environments to enable error outputting, enable the Xdebug extension, etc.:

1	$ symfony var:set php:memory_limit=256M

Settings defined as environment variables have precedence over the ones defined in .symfony.cloud.yaml, which has precedence over the ones defined in php.ini.

Error Handling¶

By default, display_errors is set to On to ease setting up your project. We strongly recommend providing a custom error handler in your application or setting this value to Off before you make your site live and this is done automatically for you during initial configuration using the project:init command:

INI
1 2
; php.ini display_errors=Off

YAML

# .symfony.cloud.yaml
variables:
    php:
        display_errors: Off

PHP Timezone¶

You can change the timezone of the PHP runtime with the following configuration:

INI

; php.ini
date.timezone="Europe/Paris

YAML

# .symfony.cloud.yaml
variables:
    php:
        "date.timezone": "Europe/Paris"

Check out the main Timezone article to learn more about setting the timezone of other services.

Runtime configuration¶

In addition to PHP Configuration, SymfonyCloud also lets you configure the PHP-FPM runtime via the runtime section on the .symfony.cloud.yaml file. The following options are configurable:

request_terminate_timeout: The timeout for serving a single request after which the PHP-FPM worker process will be killed. This option should be used when the max_execution_time ini option does not stop script execution for some reason.
1 2 3
# .symfony.cloud.yaml runtime: request_terminate_timeout: 300

sizing_hints: Hints given to SymfonyCloud to compute the optimal number of workers serving HTTP requests. See PHP Worker Sizing Hints for more information.

# .symfony.cloud.yaml
runtime:
    sizing_hints:
        # values are considered megabytes
        request_memory: 10
        reserved_memory: 70

Debug PHP-FPM¶

Use the env:fpm:status command to inspect what’s going on with PHP-FPM:

$ symfony env:fpm:status

pool:                 web
process manager:      ondemand
start time:           10/Jan/2019:08:55:43 +0000
start since:          365469
accepted conn:        17329
listen queue:         0
max listen queue:     0
listen queue len:     0
idle processes:       0
active processes:     1
total processes:      1
max active processes: 2
max children reached: 102
slow requests:        0

************************
pid:                  20216
state:                Running
start time:           14/Jan/2019:14:26:14 +0000
start since:          38
requests:             3
request duration:     155
request method:       GET
request URI:          /-/status?&full
content length:       0
user:                 -
script:               -
last request cpu:     0.00
last request memory:  0

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.