Create JSON array from python list

Question

I am currently trying to write something to convert an Ansible inventory file into a JSON array which would allow it to be pulled into awx/tower however I have struggled to build a brand new array from the current inventory file format. I am avoiding use of any of the Ansible python API modules as there is no guarantee that future updates won't break these. One solution I found no longer works as there appears to be a change to the Ansible InventoryParser python module so I'm trying to come up with a Python 2.7 solution.

Example inventory file;

[test]
host1
host2
[test1]
host3
host4

The [] signify groups and the other entries are the hosts which will be the key:value relationship. I have converted this to a list in python and I am then attempting to format this into a key:value setup using the [] as where to split the key from the values.

both = []
f = open(filename, "r")
line = f.readline().strip()
while line:
    both.append(line)
    line = f.readline().strip()
f.close()

start = '['
end = ']'
json_dict = {'all': [dict(item.split(start)[1].split(end)[0] for item in 
both)]}

print json.dumps(json_dict)

Unfortunately this returns the error: ValueError: dictionary update sequence element #0 has length 4; 2 is required

Although truth be told I'm not sure this will return what I am looking for regardless.

Hoping someone can point me in the right direction or highlight where I've gone wrong so far.

Cheers

EDIT: Adding some code for what output is actually expected;

{
[test]: {
    'hosts': ['host1', 'host2'],
    },
[test1]: {
    'hosts': ['host3', 'host4'],
    }
}

A more detailed output example of what I'm trying to achieve;

{
    "databases"   : {
        "hosts"   : [ "host1.example.com", "host2.example.com" ],
        "vars"    : {
            "a"   : true
        }
    },
    "webservers"  : [ "host2.example.com", "host3.example.com" ],
    "atlanta"     : {
        "hosts"   : [ "host1.example.com", "host4.example.com", 
"host5.example.com" ],
        "vars"    : {
            "b"   : false
        },
    },
    "marietta"    : [ "host6.example.com" ],
    "5points"     : [ "host7.example.com" ]
}

So we have a key which holds the group names and within that there are key:value pairs for hosts and vars.

After some more study I am closer to the output I desire with the following code;

both = {}
group = None

with open(filename, "r") as f:
    line = f.readline().strip()
    while line:
        if line.startswith('#') or line.startswith(';') or len(line) == 0:
            continue

        if line.startswith("["):
            # is a group
            group = line
            both[group] = {}
        elif not line.startswith("["):
            host = line
            both[group][host] = {}
        line = f.readline().strip()
f.close()

return both

Which returns the following which isn't quite what I'm after but I feel like I am making progress;

{
  "[test2]": {
    "host1": {}, 
    "host2": {}
  }, 
  "[test3]": {
    "host3": {}
  }, 
  "[test]": {
    "host4": {}, 
    "host5": {}
  }    
}

Do I understand you correctly, you want to get ['host1', 'host2', 'host3', 'host4']? — L3viathan
– L3viathan, Commented Dec 13, 2017 at 13:00
What's the actual output you're after like? You're passing an iterable of strings to dict(), which expects an iterable of iterables of length 2. Also, this seems like an XY problem. — Ilja Everilä
– Ilja Everilä, Commented Dec 13, 2017 at 13:06
I've updated the question with the expected output I am trying to achieve. — Caidran
– Caidran, Commented Dec 13, 2017 at 14:54

sanjusci · Accepted Answer · 2017-12-13 13:36:44Z

1

It's may help you.

import json
both = {}
start = '['
end = ']'
with open(filename, "r") as f:
    line = f.readline().strip()
    while line:
        if start in line or end in line:
           line = line.split(start)[1].split(end)[0]
        both[line] = line
        line = f.readline().strip()
json_dict = {'all': [both]}

print(json.dumps(json_dict))

answered Dec 13, 2017 at 13:36

sanjusci

1872 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Create JSON array from python list

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related