如何在Ubuntu上使用Python查找Apache2的配置错误？

Question

I'm following a Digital Ocean tutorial for installing Python on my laptop's Apache2 server. Ubuntu 14.04 LTS, Python 3.4.3, MySQL 14.14.

Updating the Apache config seems straightforward:

<VirtualHost *:80>
    <Directory /var/www/test>
        Options +ExecCGI
        DirectoryIndex index.py
    </Directory>
    AddHandler cgi-script .py
    ...
    DocumentRoot /var/www/test
    ...

I can restart Apache w/o issues.

The Python test script at /var/www/test/index.py also seems straightforward. I can run it from the command line w/o problems, and chmod'd the file to 755 afterwards.

#!/usr/bin/python

# Turn on debug mode.
import cgitb
cgitb.enable()

# Print necessary headers.
print("Content-Type: text/html")
print()

# Connect to the database.
import pymysql
conn = pymysql.connect(
    db='example',
    user='root',
    passwd='your_root_mysql_password',
    host='localhost')
c = conn.cursor()

# Insert some example data.
c.execute("INSERT INTO numbers VALUES (1, 'One!')")
c.execute("INSERT INTO numbers VALUES (2, 'Two!')")
c.execute("INSERT INTO numbers VALUES (3, 'Three!')")
conn.commit()

# Print the contents of the database.
c.execute("SELECT * FROM numbers")
print([(r[0], r[1]) for r in c.fetchall()])

Apache is consistently bombing out with a "500", and the access log doesn't provide further detail. I know this is something simple and there's nobody else in my office with any expertise.

Hints?

Answer 1

Try this one:

#!/usr/bin/python
import os, logging


def customLogger(name):
    logger = logging.getLogger(name)
    logger.setLevel(logging.DEBUG)
    handler = logging.FileHandler(os.path.join('/var/log/', name + '.log'), 'a')
    logger.addHandler(handler)
    return logger

error_logger = customLogger('errors_python')


# Turn on debug mode.
import cgitb
cgitb.enable()
try:
    # Print necessary headers.
    print("Content-Type: text/html")
    print()

    # Connect to the database.
    import pymysql
    conn = pymysql.connect(
        db='example',
        user='root',
        passwd='your_root_mysql_password',
        host='localhost')
    c = conn.cursor()

    # Insert some example data.
    c.execute("INSERT INTO numbers VALUES (1, 'One!')")
    c.execute("INSERT INTO numbers VALUES (2, 'Two!')")
    c.execute("INSERT INTO numbers VALUES (3, 'Three!')")
    conn.commit()

    # Print the contents of the database.
    c.execute("SELECT * FROM numbers")
    print([(r[0], r[1]) for r in c.fetchall()])
except Exception as e:
    error_logger.exception("Error")

Open in browser and then check /var/log/errors_python.log file. If file empty then looks like wrong apache2 configuration. In other scenario you will see all errors.

Answer 2

Well, that was weird.

I noticed that a related SO question omitted the parens after the 2nd print statement. Apparently it's related to Apache throwing an error if a blank line is not included after the header. (Props to @robertklep for the insight.)

Refreshing the page after the edit revealed a 'missing module' error. Fixed via a sudo pip install, and I'm back in business. Thanks all!