Author: masnun

Linux

Debugging MongoDB Connection Issues

Post author By masnun
Post date March 8, 2014

I am working on a project where I connect to MongoDB from PHP using the PECL extension. Regardless of your stack, we might time to time face strange issues when our clients can’t connect to the mongodb server. In this post, I would document what I did in my case.

First test if the mongodb server can be connected to. Use the “mongo” shell client.

mongo --host localhost:27017

1	mongo --host localhost:27017

If the connection succeeds, then the server is definitely reachable. You have made some mistakes in configuring your client. A very common mistake is having a malformed connection URI. So double check if you typed in your host, port and other details properly in the connection string.

If the above fails, that means the server is not responding. To begin with, try restarting it.

sudo service mongodb restart

1	sudo service mongodb restart

If the server started well, try again. Still connection failed? OK, the server might be damaged. How about checking the log files?

tail -f /var/log/mongodb/mongodb.log

1	tail -f /var/log/mongodb/mongodb.log

Nothing interesting? Or do not understand the format? Well, then let’s try blindly repairing the server:

sudo rm /var/lib/mongodb/mongod.lock   
sudo -u mongodb mongod -f /etc/mongodb.conf --repair 
sudo service mongodb start

sudo rm /var/lib/mongodb/mongod.lock

sudo -u mongodb mongod -f /etc/mongodb.conf --repair

sudo service mongodb start

Your problem should be resolved by now. But if it doesn’t solve the issue, your problem is not a common one. Try Googling further or asking on StackOverflow or other programming forums.

PHP

Using PhpStorm from Command Line

Post author By masnun
Post date February 23, 2014
2 Comments on Using PhpStorm from Command Line

I know the title is not so interesting because we all know PhpStorm can be launched from the command line just using the “pstorm” command. Like this:

pstorm

pstorm

But I love the word “storm” more than “pstorm”, so I did this in my .zshrc:

alias storm=pstorm

1	alias storm=pstorm

How do we open a directory in PhpStorm? Just like the usual:

storm .

storm .

Ah, that will open the current directory in PS 🙂

But what if the command line tool was not installed properly? What if, while upgrading, the tool broke? Or if like me, you install EAPs all the time to try out new features and the command line tool can’t find the EAP version’s path? Well, in this blog post, I will share the python script that is actually installed as the “pstorm” tool. I will also tell you what to modify in case it can’t find your PhpStorm. And of course, we will see how to install it.

So first, the python script. If it’s installed on your system, you can view the content:

cat `which pstorm`

1	cat `which pstorm`

Or to edit it with your preferred text editor (in my case vim):

vim `which pstorm`

1	vim `which pstorm`

If you don’t have the script installed, here’s mine:

#!/usr/bin/python

import socket
import struct
import sys
import os
import time

# see com.intellij.idea.SocketLock for the server side of this interface

RUN_PATH = '/Applications/PhpStorm EAP.app'
CONFIG_PATH = '/Users/masnun/Library/Preferences/WebIde70'

args = []
skip_next = False
for i, arg in enumerate(sys.argv[1:]):
    if arg == '-h' or arg == '-?' or arg == '--help':
        print(('Usage:\n' + \
               '  {0} -h |-? | --help\n' + \
               '  {0} [-l|--line line] file[:line]\n' + \
               '  {0} diff file1 file2').format(sys.argv[0]))
        exit(0)
    elif arg == 'diff' and i == 0:
        args.append(arg)
    elif arg == '-l' or arg == '--line':
        args.append(arg)
        skip_next = True
    elif skip_next:
        args.append(arg)
        skip_next = False
    else:
        if ':' in arg:
            filepath, line_number = arg.rsplit(':', 1)
            if line_number.isdigit():
              args.append('-l')
              args.append(line_number)
              args.append(os.path.abspath(filepath))
            else:
              args.append(os.path.abspath(arg))
        else:
            args.append(os.path.abspath(arg))

def launch_with_port(port):
    found = False

    s = socket.socket()
    s.settimeout(0.3)
    try:
        s.connect(('127.0.0.1', port))
    except:
        return False
   
    while True:
        try:
            path_len = struct.unpack(">h", s.recv(2))[0]
            path = s.recv(path_len)
            path = os.path.abspath(path)
            if os.path.abspath(path) == os.path.abspath(CONFIG_PATH):
                found = True
                break
        except:
            break
    
    if found:
        if args:
            cmd = "activate " + "\0".join(args)
            encoded = struct.pack(">h", len(cmd)) + cmd
            s.send(encoded)
            time.sleep(0.5)   # don't close socket immediately
        return True

    return False

port = -1
try:
    f = open(os.path.join(CONFIG_PATH, 'port'))
    port = int(f.read())
except Exception:
    type, value, traceback = sys.exc_info()
    print(value)
    port = -1

if port == -1:
    # SocketLock actually allows up to 50 ports, but the checking takes too long
    for port in range(6942, 6942+10):
        if launch_with_port(port): exit()
else:
    if launch_with_port(port): exit()

if sys.platform == "darwin":
    # Mac OS: RUN_PATH is *.app path
    if len(args):
        args.insert(0, "--args")
    os.execvp("open", ["-a", RUN_PATH] + args)
else:
    # unix common
    bin_dir, bin_file = os.path.split(RUN_PATH)
    os.chdir(bin_dir)
    os.execv(bin_file, [bin_file] + args)

#!/usr/bin/python

import socket

import struct

import sys

import os

import time

# see com.intellij.idea.SocketLock for the server side of this interface

RUN_PATH = '/Applications/PhpStorm EAP.app'

CONFIG_PATH = '/Users/masnun/Library/Preferences/WebIde70'

args = []

skip_next = False

for i, arg in enumerate(sys.argv[1:]):

if arg == '-h' or arg == '-?' or arg == '--help':

print(('Usage:\n' + \

' {0} -h |-? | --help\n' + \

' {0} [-l|--line line] file[:line]\n' + \

' {0} diff file1 file2').format(sys.argv[0]))

exit(0)

elif arg == 'diff' and i == 0:

args.append(arg)

elif arg == '-l' or arg == '--line':

args.append(arg)

skip_next = True

elif skip_next:

args.append(arg)

skip_next = False

else:

if ':' in arg:

filepath, line_number = arg.rsplit(':', 1)

if line_number.isdigit():

args.append('-l')

args.append(line_number)

args.append(os.path.abspath(filepath))

else:

args.append(os.path.abspath(arg))

else:

args.append(os.path.abspath(arg))

def launch_with_port(port):

found = False

s = socket.socket()

s.settimeout(0.3)

try:

s.connect(('127.0.0.1', port))

except:

return False

while True:

try:

path_len = struct.unpack(">h", s.recv(2))[0]

path = s.recv(path_len)

path = os.path.abspath(path)

if os.path.abspath(path) == os.path.abspath(CONFIG_PATH):

found = True

break

except:

break

if found:

if args:

cmd = "activate " + "\0".join(args)

encoded = struct.pack(">h", len(cmd)) + cmd

s.send(encoded)

time.sleep(0.5) # don't close socket immediately

return True

return False

port = -1

try:

f = open(os.path.join(CONFIG_PATH, 'port'))

port = int(f.read())

except Exception:

type, value, traceback = sys.exc_info()

print(value)

port = -1

if port == -1:

# SocketLock actually allows up to 50 ports, but the checking takes too long

for port in range(6942, 6942+10):

if launch_with_port(port): exit()

else:

if launch_with_port(port): exit()

if sys.platform == "darwin":

# Mac OS: RUN_PATH is *.app path

if len(args):

args.insert(0, "--args")

os.execvp("open", ["-a", RUN_PATH] + args)

else:

# unix common

bin_dir, bin_file = os.path.split(RUN_PATH)

os.chdir(bin_dir)

os.execv(bin_file, [bin_file] + args)

If you know Python, feel free to read and understand what’s actually doing. Now, this script needs to know two things:

— The path to PhpStorm directory (where the executable is)
— The preferences directory

You should be able to find the first trying to locate where PhpStorm is installed. For the second, it’s actually platform dependent. On OS X, it’s inside the “Home” > “Library” > “Preferences” > “WebIde**” directory.

The preference directories are named with a zero appended to the major version of PhpStorm. So, for PS 7.x it’s WebIde70. For 6.x, it’s WebIde60.

Just configure the two variables in the script. Then copy it to your path, in my case, I have “~/.bin” added to my PATH. So I did this:

cp pstorm ~/.bin/pstorm
chmod a+x ~/.bin/pstorm

1 2	cp pstorm ~/.bin/pstorm chmod a+x ~/.bin/pstorm

The last line makes it executable. Now open a new terminal and try the “pstorm” command.

Python

Embed a Python REPL in your program

Post author By masnun
Post date January 9, 2014

So you love the Django shell? The interactive prompt that has your Django stuff loaded and ready for some quick prototyping? You always wanted to embed something similar in your Python apps too? Well, it’s painlessly simple with the “code” module. It offers us the “InteractiveConsole” class which we can extend to quickly get a REPL which is basically the Python REPL with our customizations. The code is heavily documented. Going through it should be adequate to understand whats going on:

from code import InteractiveConsole

# Our own console implementation
# Subclasses object since we want to use new style classes

class MySuperCoolConsole(InteractiveConsole, object):

    # Redefine interact method to add our own banners
    # Subclassing was necessary, we could pass it to
    # a new InteractiveConsole instance directly

    def interact(self):
        banner = "=====" * 3 + "\n" + "SUPER COOL CONSOLE" + "\n" + "VERSION: 0.1" + "\n" + "=====" * 3
        super(MySuperCoolConsole, self).interact(banner)

    # Customize the prompt
    def raw_input(self, prompt=""):
        prompt = "[=>] "
        return raw_input(prompt)


# We want to inject some preset variables ("names" in Python)
# Grab the locals(), add our own to it
local_names = locals()
local_names['name'] = 'masnun'
local_names['email'] = 'masnun@transcendio.net'

# Pass the modified locals, call interact to launch REPL
console = MySuperCoolConsole(locals=local_names)
console.interact()

from code import InteractiveConsole

# Our own console implementation

# Subclasses object since we want to use new style classes

class MySuperCoolConsole(InteractiveConsole, object):

# Redefine interact method to add our own banners

# Subclassing was necessary, we could pass it to

# a new InteractiveConsole instance directly

def interact(self):

banner = "=====" * 3 + "\n" + "SUPER COOL CONSOLE" + "\n" + "VERSION: 0.1" + "\n" + "=====" * 3

super(MySuperCoolConsole, self).interact(banner)

# Customize the prompt

def raw_input(self, prompt=""):

prompt = "[=>] "

return raw_input(prompt)

# We want to inject some preset variables ("names" in Python)

# Grab the locals(), add our own to it

local_names = locals()

local_names['name'] = 'masnun'

local_names['email'] = 'masnun@transcendio.net'

# Pass the modified locals, call interact to launch REPL

console = MySuperCoolConsole(locals=local_names)

console.interact()

What did we do? We subclassed InteractiveConsole to create our own implementation. And then ran it 🙂

Test run outputs:

~/Codes/py ⮀ python test.py
===============
SUPER COOL CONSOLE
VERSION: 0.1
===============
[=>] email
'masnun@transcendio.net'
[=>] name
'masnun'
[=>] print 'those were injected'
those were injected
[=>] print 'nice, no?'
nice, no?
[=>] 2 + 3
5
[=>] ^D
 ~/Codes/py ⮀

~/Codes/py ⮀ python test.py

===============

SUPER COOL CONSOLE

VERSION: 0.1

===============

[=>] email

'masnun@transcendio.net'

[=>] name

'masnun'

[=>] print 'those were injected'

those were injected

[=>] print 'nice, no?'

nice, no?

[=>] 2 + 3

[=>] ^D

~/Codes/py ⮀

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