HOCON parser for Python
https://github.com/typesafehub/config/blob/master/HOCON.md
It is available on pypi so you can install it as follows:
$ pip install pyhocon
The parsed config can be seen as a nested dictionary (with types automatically inferred) where values can be accessed using normal
dictionary getter (e.g., conf['a']['b'] or using paths like conf['a.b']) or via the methods get, get_int (throws an exception
if it is not an int), get_string, get_list, get_float, get_bool, get_config.
from pyhocon import ConfigFactory
conf = ConfigFactory.parse_file('samples/database.conf')
host = conf.get_string('databases.mysql.host')
same_host = conf.get('databases.mysql.host')
same_host = conf['databases.mysql.host']
same_host = conf['databases']['mysql.host']
port = conf['databases.mysql.port']
username = conf['databases']['mysql']['username']
password = conf.get_config('databases')['mysql.password']
password = conf.get('databases.mysql.password', 'default_password') # use default value if key not found
//
// You can use # or // for comments
//
{
databases {
# MySQL
active = true
enable_logging = false
resolver = null
# you can use substitution with unquoted strings. If it it not found in the document, it defaults to environment variables
home_dir = ${HOME} # you can substitute with environment variables
"mysql" = {
host = "abc.com" # change it
port = 3306 # default
username: scott // can use : or =
password = tiger, // can optionally use a comma
// number of retries
retries = 3
}
}
// multi line support
motd = """
Hello "man"!
How is it going?
"""
// this will be appended to the databases dictionary above
databases.ips = [
192.168.0.1 // use white space or comma as separator
"192.168.0.2" // optional quotes
192.168.0.3, # can have a trailing , which is ok
]
# you can use substitution with unquoted strings
retries_msg = You have ${databases.mysql.retries} retries
# retries message will be overriden if environment variable CUSTOM_MSG is set
retries_msg = ${?CUSTOM_MSG}
}
// dict merge
data-center-generic = { cluster-size = 6 }
data-center-east = ${data-center-generic} { name = "east" }
// list merge
default-jvm-opts = [-XX:+UseParNewGC]
large-jvm-opts = ${default-jvm-opts} [-Xm16g]
We provide a conversion tool to convert from HOCON to the JSON, .properties and YAML formats.
usage: pyhocon [-h] [-i INPUT] [-o OUTPUT] [-f FORMAT]
pyhocon tool
optional arguments:
-h, --help show this help message and exit
-i INPUT, --input INPUT FILE
-o OUTPUT, --output OUTPUT FILE
-f FORMAT, --format FORMAT
output format: json, properties or yaml
If -i is omitted, the tool will read from the standard input. If -o is omitted, the result will be written to the standard output.
$ cat samples/database.conf | pyhocon -f json
{
"databases": {
"active": true,
"enable_logging": false,
"resolver": null,
"home_dir": "/Users/darthbear",
"mysql": {
"host": "abc.com",
"port": 3306,
"username": "scott",
"password": "tiger",
"retries": 3
},
"ips": [
"192.168.0.1",
"192.168.0.2",
"192.168.0.3"
]
},
"motd": "\n Hello \"man\"!\n How is it going?\n ",
"retries_msg": "You have 3 retries"
}
$ cat samples/database.conf | pyhocon -f properties
databases.active = true
databases.enable_logging = false
databases.home_dir = /Users/darthbear
databases.mysql.host = abc.com
databases.mysql.port = 3306
databases.mysql.username = scott
databases.mysql.password = tiger
databases.mysql.retries = 3
databases.ips.0 = 192.168.0.1
databases.ips.1 = 192.168.0.2
databases.ips.2 = 192.168.0.3
motd = \
Hello "man"\!\
How is it going?\
retries_msg = You have 3 retries
$ cat samples/database.conf | pyhocon -f yaml
databases:
active: true
enable_logging: false
resolver: None
home_dir: /Users/darthbear
mysql:
host: abc.com
port: 3306
username: scott
password: tiger
retries: 3
ips:
- 192.168.0.1
- 192.168.0.2
- 192.168.0.3
motd: |
Hello "man"!
How is it going?
retries_msg: You have 3 retries
We support the include semantics using one of the followings:
include "test.conf"
include "http://abc.com/test.conf"
include "https://abc.com/test.conf"
include "file://abc.com/test.conf"
include file("test.conf")
include url("http://abc.com/test.conf")
include url("https://abc.com/test.conf")
include url("file://abc.com/test.conf")
When one uses a relative path (e.g., test.conf), we use the same directory as the file that includes the new file as a base directory. If the standard input is used, we use the current directory as a base directory.
For example if we have the following files:
cat.conf:
{
garfield: {
say: meow
}
}
dog.conf:
{
mutt: {
say: woof
hates: {
garfield: {
notes: I don't like him
say: meeeeeeeooooowww
}
include "cat.conf"
}
}
}
animals.conf:
{
cat : {
include "cat.conf"
}
dog: {
include "dog.conf"
}
}
Then evaluating animals.conf will result in the followings:
$ pyhocon -i samples/animals.conf
{
"cat": {
"garfield": {
"say": "meow"
}
},
"dog": {
"mutt": {
"say": "woof",
"hates": {
"garfield": {
"notes": "I don't like him",
"say": "meow"
}
}
}
}
}
As you can see, the attributes in cat.conf were merged to the ones in dog.conf. Note that the attribute "say" in dog.conf got overwritten by the one in cat.conf.
| Items | Status |
|---|---|
| Comments | ✅ |
| Omit root braces | ✅ |
| Key-value separator | ✅ |
| Commas | ✅ |
| Whitespace | ✅ |
| Duplicate keys and object merging | ✅ |
| Unquoted strings | ✅ |
| Multi-line strings | ✅ |
| String value concatenation | ✅ |
| Array concatenation | ✅ |
| Object concatenation | ✅ |
| Arrays without commas | ✅ |
| Path expressions | ✅ |
| Paths as keys | ✅ |
| Substitutions | ✅ |
| Self-referential substitutions | ❌ |
The += separator |
❌ |
| Includes | ✅ |
| Include semantics: merging | ✅ |
| Include semantics: substitution | ✅ |
| Include semantics: missing files | ❌ |
| Include semantics: file formats and extensions | ❌ |
| Include semantics: locating resources | ❌ |
| Include semantics: preventing cycles | ❌ |
| Conversion of numerically-index objects to arrays | ❌ |
| API Recommendations | Status |
|---|---|
| Conversion of numerically-index objects to arrays | ❌ |
| Automatic type conversions | ❌ |
| Units format | ❌ |
| Duration format | ❌ |
| Size in bytes format | ❌ |
| Config object merging and file merging | ❌ |
| Java properties mapping | ❌ |