Minimal Python module for using the GNS3 API for both v2 and v3

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Currently I use both GNS3 v2.2 and v3.0(beta). When using the API I would like to use the same python module supporting both versions. So I created a tiny one, that just fulfills my basic needs.

It get initialized by api = gns3api_mini.GNS3Api(gns3_server_url, user, password). It creates a connection to the server and automatically detect the API version (available in api.version).

The main method is api.request(method, path, args=None, timeout=60). It automatically converts the Python data to JSON and vice versa.

In addition, the module contains the get, put, post, and delete functions, which are wrappers around api.request and call the API with the appropriate method.

If the path is a list or a tuple, the components are concatenated with "/" as the separator. If the path doesn't start with a "/" the version ("/v2/" or "/v3/") is prefixed. Of course, this prefixing makes only sense for API methods, that are available both in v2 and v3 and use similar parameters.

The API module even supports image I/O. For uploading the args parameter must be either a byte string containing the image or a file type object. For downloading api.request returns a file type object with the image data.

Here the API module gns3api_mini.py.txt, remove the txt extension after downloading.

And here a test program:

#!/usr/bin/env python3

import argparse
import io
import json
import gns3api_mini

parser = argparse.ArgumentParser(description='%(prog)s tests gns3api_mini')
parser.add_argument('-u', '--user', default='', metavar='user:pass',
                    help='user authentication')
parser.add_argument('url', metavar='URL', help='GNS3 server URL')
args = parser.parse_args()
user, *password = args.user.split(":", 1)
password = (password + [''])[0]

api = gns3api_mini.GNS3Api(args.url, user, password)
print(f"Version = {api.version}")

print()
print('GET templates')
templates = api.get('templates')
print(json.dumps(templates[0:2], indent=4, separators=(',', ': ')))

# v2 specific image I/O
if api.version.startswith("2."):
    print()
    print('GET /v2/compute/qemu/images/empty8G.qcow2')
    resp = api.get('/v2/compute/qemu/images/empty8G.qcow2')
    data = resp.read()
    print(f"Data size: {len(data)}")

    print()
    print('POST /v2/compute/qemu/images/test_upload.img')
    with io.BytesIO(data) as img_file:
        api.post('/v2/compute/qemu/images/test_upload.img', img_file)
    print(f"Status: {api.status_code}")

# v3 specific image I/O
if api.version.startswith("3."):
    print()
    try:
        print('DELETE /v3/images/test_upload.img')
        api.delete('/v3/images/test_upload.img')
    except gns3api_mini.HTTPResponseError as err:
        print(str(err))
    print('POST /v3/images/upload/test_upload.img')
    with io.BytesIO(b'Test\nLine 2\n') as img_file:
        status = api.post('/v3/images/upload/test_upload.img', img_file)
        print(json.dumps(status, indent=4, separators=(',', ': ')))

print()
print('GET version')
data = api.get('version')
print(data['version'])