a2conf 0.3.1

apache2 configuration file parser and query tool

a2conf

a2conf is python3 module which provides easy way to configure apache2. a2conf used by a2utils package, so you may use a2utils as examples.

For all examples we will use test config file examples/example.conf in source code. Use export PYTHONPATH=. to use module if it's not installed.

Create simple apache config

see examples/ex5_create.py for full code:

vhost = root.insert('<VirtualHost *:80>')
vhost.insert([
        '# This VirtualHost is auto-generated',
        'ServerName example.com', 
        'ServerAlias www.example.com', 
        '', 
        'DocumentRoot /var/www/example.com/'
        ])

Read apache config

list all SSL hosts (see examples/ex2_query.py for full code):

root = a2conf.Node(config)
for vhost in root.children('<VirtualHost>'):
    servername = vhost.first('servername').args # First query method, via first(). Not much fail-safe but short.

    try:
        ssl_option = next(vhost.children('sslengine')).args # Second query method, via children()
        if ssl_option.lower() == 'on':
            print("{} has SSL enabled".format(servername))
    except StopIteration:
        # No SSL Engine directive in this vhost
        pass

Get VirtualHost

        root = a2conf.Node(config)
        vh1 = root.find_vhost('example.com', '*:80')
        vh2 = root.find_vhost('www.example.com', '*:443')
        vh3 = root.find_vhost('example.example.com')

Node class

Properties

raw - text line as-is, with all spaces, tabs and with comments

cmd - cmd ('ServerName') without args or None (if section)

section - section (e.g. 'VirtualHost')

args - one text line args to cmd or section. for vhost args could be '*:80', for ServerAlias: 'example.com example.org'

name - name of node. cmd if node has cmd, or section name (in brackets) if this is section. e.g. 'ServerName' or ''

content - list of child nodes (possible empty). For container sections (VirtualHost) attribute content is list of children. For usual commands (e.g. ServerName) - empty list.

Methods

__init__(self, read=filename, raw=None, parent=None, name=None, path=None, line=None, includes=True) - In most cases you should not need to use any parameters here except includes and read. read is apache config filename to read. Use includes=False if you want read_file method to ignore Include* directives.

children(name=None, recursive=None) - Main query method, returns generator for all children nodes (e.g. for VirtualHost node). Generator is empty if no children. If name specified, generator will return only nodes with this name (e.g. 'servername' or ''). If recursive is On, generator will return nested nodes too (e.g. what is inside <IfModule> or <Directory> settings). To get just one first element use next(node.children('ServerName')). It will raise StopIteration if node has no such children elements.

first(name, recursive=None) - wrapper for children(). Returns only first element or None. Not raising exceptions.

read_file(filename) - Reads apache config. Called automatically from __init__ if you specified read argument.

dump(fh=sys.stdout, depth=0) - dump loaded config in unified format (indented). if fh not specified, just dumps to stdout()

write_file(filename) - opens file for writing and dump() to this file.

add(child) - add new child node to content of Node after all other nodes (including possible closing Node </VirtualHost>). Child is Node type, use add_raw(line) to add raw string.

insert(child, after) - smarter then add(). Add new child node, place it after last node with name after. e.g.:

doc_root = Node(raw='DocumentRoot /var/www/site1')
vhost.insert([doc_root], after=['ServerName','ServerAlias'])

child is list of Nodes to insert. But a2conf is friendly: if you pass single element, it will be converted to list with this element, and then if any element is string, it will be converted to node. So, this command woks well too:

vhost.insert('DocumentRoot /var/www/site1', after=['ServerName','ServerAlias'])

If after not specified, or not found, child is appended to end. If specified, method tries to insert new node after last found node in after.

In this example, new node will be inserted after ServerAlias (if it exists). If not, it will be inserted after ServerName (if it exists). And if all commands listed in after is not found, node will be inserted as last node, right before closing tag (e.g., right before </VirtualHost>).

Returns first inserted child. So you may write code like this:

# Create virtualhost for example.net
vhost = root.insert("<VirtualHost *:80>")
vhost.insert('ServerName example.net')

delete() - removes this Node from parent (e.g. remove vhost from apache config or remove directive from vhost). You should not call delete() while iterating over children() (unless you want to delete just one node). Proper usage:

    # Bad way, it will delete only one node:
    for n in vhost.children('Redirect'):
        n.delete() 

    # Proper way
    deleted=list()
    for n in vhost.children('Redirect'):
        deleted.append(n)
    for n in deleted:
        n.delete()

Examples

Just dump apache config

examples/ex1_dump.py just loads config and dumps its structure (without comments) as JSON:

#!/usr/bin/env python3
import sys
import a2conf
import json

root = a2conf.Node(sys.argv[1])

def section_dump(node):
    data = dict()

    for ch in node.children():
        if ch.section and not ch.section.startswith('/'):
            if ch.args:
                key = ch.section + ' ' + ch.args
            else:
                key = ch.section
            data[key] = section_dump(ch)
        elif ch.cmd:
            data[ch.cmd] = ch.args
    return data

data = section_dump(root)
print(json.dumps(data, indent=4))

Output:

$ examples/ex1_dump.py examples/example.conf
{
    "VirtualHost *:80": {
        "DocumentRoot": "/var/www/example",
        "ServerName": "example.com",
        "ServerAlias": "www.example.com example.com 1.example.com 2.example.com",
        "DirectoryIndex": "index.html index.htm default.htm index.php",
        "Options": "-Indexes +FollowSymLinks"
    },
    "VirtualHost *:443": {
        "DocumentRoot": "/var/www/example",
        "ServerName": "example.com",
        "ServerAlias": "www.example.com 1.example.com 2.example.com secure.example.com",
        "DirectoryIndex": "index.html index.htm default.htm index.php",
        "Options": "-Indexes +FollowSymLinks",
        "SSLEngine": "On",
        "SSLCertificateFile": "/etc/letsencrypt/live/example.com/fullchain.pem",
        "SSLCertificateKeyFile": "/etc/letsencrypt/live/example.com/privkey.pem",
        "SSLCertificateChainFile": "/etc/letsencrypt/live/example.com/chain.pem"
    }
}

Note - this is short example just for demo, it's not very good for production: if virtualhost has more then one directive (e.g. ServerAlias, RewriteRule, RewriteCond), only last one will be used.

Query

examples/ex2_query.py print all SSL sites from config:

#!/usr/bin/env python3
import sys
import a2conf
root = a2conf.Node(sys.argv[1])

for vhost in root.children('<VirtualHost>'):
    servername = vhost.first('servername').args # One query method, via first(). Not much fail-safe but short.

    try:
        ssl_option = next(vhost.children('sslengine')).args # Other query method, via children()
        if ssl_option.lower() == 'on':
            print("{} has SSL enabled".format(servername))
    except StopIteration:
        # No SSL Engine directive in this vhost
        continue

Output:

$ examples/ex2_query.py examples/example.conf
example.com has SSL enabled

Replace and delete

examples/ex3_replace_delete.py disables SSLEngine directive:

#!/usr/bin/env python3
import sys
import a2conf
root = a2conf.Node(sys.argv[1])

for vhost in root.children('<VirtualHost>'):
    if vhost.first('sslengine'):
        vhost.delete() # Delete SSL vhost
    else:
        # Modify DocumentRoot
        vhost.first('DocumentRoot').args = '/var/www/example2'
        vhost.first('DocumentRoot').suffix = '# New DocumentRoot!'
        # Delete ServerAlias
        vhost.first('ServerAlias').delete()

root.dump()

Output:

$ examples/ex3_replace_delete.py examples/example.conf
#
# Example config file for a2conf
#
<VirtualHost *:80>
    # Non-ssl site
    DocumentRoot /var/www/example2 # New DocumentRoot!
    ServerName example.com # .... OUR TEST SITE ....
    DirectoryIndex index.html index.htm default.htm index.php
    Options -Indexes +FollowSymLinks
</VirtualHost>