Display PHP-FPM (FastCGI Process Manager) pool information using UNIX socket and Python script. I thought it would be easy to write a simple FCGI client. Apparently not, but it was an exciting and rewarding experience.
I have already described how to enable the PHP-FPM status page, so I will skip this step today.
Look at the end of this blog post for additional information, including FastCGI specification.
Python script
It is the most straightforward implementation without external dependencies.
#!/usr/bin/env python
import sys
import socket
import struct
class FCGIStatusClient:
# FCGI protocol version
FCGI_VERSION = 1
# FCGI record types
FCGI_BEGIN_REQUEST = 1
FCGI_PARAMS = 4
# FCGI roles
FCGI_RESPONDER = 1
# FCGI header length
FCGI_HEADER_LENGTH = 8
def __init__(self, socket_path = "/var/run/php/php7.0-fpm.sock", socket_timeout = 5.0, status_path = "/status" ):
self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.socket_path = socket_path
self.set_socket_timeout(socket_timeout)
self.status_path = status_path
self.request_id = 1
self.params = {
"SCRIPT_NAME": status_path,
"SCRIPT_FILENAME": status_path,
"QUERY_STRING": "",
"REQUEST_METHOD": "GET",
}
def set_socket_timeout(self, timeout):
self.socket_timeout = timeout
self.socket.settimeout(self.socket_timeout)
def connect(self):
try:
self.socket.connect(self.socket_path)
except:
print(sys.exc_info()[1])
sys.exit(1)
def close(self):
self.socket.close()
def define_begin_request(self):
fcgi_begin_request = struct.pack("!HB5x", self.FCGI_RESPONDER, 0)
fcgi_header = struct.pack("!BBHHBx", self.FCGI_VERSION, self.FCGI_BEGIN_REQUEST, self.request_id, len(fcgi_begin_request), 0)
self.fcgi_begin_request = fcgi_header + fcgi_begin_request
def define_parameters(self):
parameters = []
for name, value in self.params.items():
parameters.append(chr(len(name)) + chr(len(value)) + name + value)
parameters = ''.join(parameters)
parameters_length = len(parameters)
parameters_padding_req = parameters_length & 7
parameters_padding = b'\x00' * parameters_padding_req
fcgi_header_start = struct.pack("!BBHHBx", self.FCGI_VERSION, self.FCGI_PARAMS, self.request_id, parameters_length , parameters_padding_req)
fcgi_header_end = struct.pack("!BBHHBx", self.FCGI_VERSION, self.FCGI_PARAMS, self.request_id, 0, 0)
self.fcgi_params = fcgi_header_start + parameters.encode() + parameters_padding + fcgi_header_end
def execute(self):
try:
self.socket.send(self.fcgi_begin_request)
self.socket.send(self.fcgi_params)
header = self.socket.recv(self.FCGI_HEADER_LENGTH)
fcgi_version, request_type, request_id, request_length, request_padding = struct.unpack("!BBHHBx", header)
if request_type == 6:
self.raw_status_data=self.socket.recv(request_length)
else:
self.raw_status_data = ""
if request_type == 7:
raise Exception("Received an error packet.")
else:
raise Exception("Received unexpected packet type.")
except:
print(sys.exc_info()[1])
sys.exit(2)
self.status_data = self.raw_status_data.decode().split("\r\n\r\n")[1]
def make_request(self):
self.define_begin_request()
self.define_parameters()
self.connect()
self.execute()
self.close()
def print_status(self):
print(self.status_data)
fcgi_client = FCGIStatusClient( socket_path = "/var/run/php/php7.0-fpm.sock", status_path = "/status" )
fcgi_client.make_request()
fcgi_client.print_status()
Sample usage
This script returns pool statistics and can be easily extended to report data using the desired format.
$ sudo -u www-data /usr/local/bin/fcgi_status.py pool: www process manager: dynamic start time: 15/Aug/2018:14:29:57 +0000 start since: 114173 accepted conn: 392 listen queue: 0 max listen queue: 0 listen queue len: 0 idle processes: 1 active processes: 1 total processes: 2 max active processes: 2 max children reached: 0 slow requests: 0