How can I set default values for SafeConfigParser?

Question

I have a config file as follows:

[job]
mailto=bob
logFile=blahDeBlah.txt

I want to read the options using SafeConfigParser:

values = {} 
config = ConfigParser.SafeConfigParser()
try:
    config.read(configFile)
    jobSection = 'job'

    values['mailto'] = config.get( jobSection, 'mailto' )
    values['logFile'] = config.get( jobSection, 'logFile' )
    # it is not there
    values['nothingThere'] = config.get( jobSection, 'nothingThere' )
.... # rest of code

The last line of course will throw an error. How can I specify a default value for the config.get() method?

Then again, if I have an options file as follows:

[job1]
mailto=bob
logFile=blahDeBlah.txt

[job2]
mailto=bob
logFile=blahDeBlah.txt

There seems to be no way to specify default options for job1 different from the default options in section job2.

These are actually two separate questions. – Niels Bom Sep 04 '15 at 13:42 — Niels Bom, Sep 04 '15 at 13:42

score 23 · Answer 1 · answered May 24 '11 at 08:00

23

Use the defaults parameter to the constructor:

# class ConfigParser.SafeConfigParser([defaults[, dict_type]]) 
#
config = ConfigParser.SafeConfigParser({'nothingThere': 'lalalalala'})
...
...
# If the job section has no "nothingThere", "lalalalala" will be returned
# 
config.get(jobSection, 'nothingThere')

answered May 24 '11 at 08:00

Eli Bendersky

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Todah, I was confused that there seems to be no way to specify the [section] name for the default. I'll try it today. – Martlark May 24 '11 at 22:28
12

I do not understand how this answers the question. What if defaults should be different for job1 and job2? – CPBL Mar 07 '16 at 15:35
This won't actually work because "nothingThere" automatically gets lowercased to "nothingthere". If you want option names to be case-sensitive you need to do config.optionxform=str, then config.set('DEFAULT', 'nothingThere', 'lalalalala') – timidpueo Dec 09 '16 at 22:48

score 22 · Accepted Answer · edited Jul 02 '23 at 01:55

22

You can also use a default ".ini" file and read it before your actual config file.

default.ini:

[job1]
mailto=jack
logfile=default.log

[job2]
mailto=john
logfile=default.log

config.ini:

[job1]
mailto=sparrow
logfile=blah.log

[job2]
logfile=blah2.log

parsing:

import ConfigParser  # For Python 3 use the configparser module instead (all lowercase)

config = ConfigParser.SafeConfigParser()
config.read('default.ini')
config.read('config.ini')

print config.get('job1', 'mailto')
# -> sparrow (from config.ini)

print config.get('job1', 'logfile')
# -> blah.log (from config.ini)

print config.get('job2', 'mailto')
# -> john (from default.ini)

print config.get('job2', 'logfile')
# -> blah2.log (from config.ini)

edited Jul 02 '23 at 01:55

Wenuka

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answered Dec 08 '16 at 14:51

Manokha

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I think this is the best answer to the OP question – Luke101 Jun 06 '18 at 17:50
@Luke101 it's kind of awkward when distributing a package though. You have to distribute the default.ini in the package data and jump through some hoops to read it back when you need it. – Ben Farmer Jan 25 '23 at 00:17
@Ben Farmer - In that case you can embed your default ini inside the program as a multiline string and replace `config.read('default.ini')` with `config.read_string(mydefaultstring)` – Chris Maurer Aug 30 '23 at 20:02

Andy White · Answer 3 · 2017-04-26T15:40:03.577

18

In Python 3 you can provide a fallback value to the get() method as follows:

values['nothingThere'] = config.get('job', 'nothingThere', fallback=0)
print(values['nothingThere'])
# -> 0

edited Apr 26 '17 at 15:40

answered Apr 26 '17 at 13:14

Andy White

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The default value is already provided by the second argument, and I have never seen a `fallback` argument. Can you point to some documentation? – Mad Physicist Apr 26 '17 at 13:48
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Note that this is the parser-level get method, not the section's get method, hence the second argument is the key, not a default value. Documentation here - https://docs.python.org/3/library/configparser.html#fallback-values – Andy White Apr 26 '17 at 15:25
@MadPhysicist It depends how you use the ConfigParser. You can either call it with `config["my_section"].get("my_option", "fallback_value")` (and here, indeed the second argument "fallback_value" will be the default value) or with `config.get("my_section", "my_option", fallback="fallback_value")` (and here the two first arguments are to specify which option of which section you want to get) – Florentin Le Moal Feb 27 '18 at 10:21
This is exactly what I want. Thanks. – EsmaeelE Feb 16 '21 at 13:53

score 11 · Answer 4 · edited Sep 04 '15 at 13:44

11

You can use the [DEFAULT] section to set default values for the properties you haven't defined in any other section(s).

E.g.

[DEFAULT]
checkout_root: /data/workspace

[pingpong]
name: Ping Pong App
checkout_root: /home/pingpong
src: %(checkout_root)s/src

[dingdong]
name: Ding Dong App
src: %(checkout_root)s/dingdong_src

For the ding ding app, the value of src will be /data/workspace/dingdong_src

edited Sep 04 '15 at 13:44

Niels Bom

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answered Mar 11 '12 at 22:08

Kaushalya

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This answer is the answer to the second question of OP. – Niels Bom Sep 04 '15 at 13:44

How can I set default values for SafeConfigParser?

4 Answers4