如何在 Google 云上获取计算引擎实例的数量 运行

Question

在 Google 云文档中，获取 Google 云中项目 运行 的实例列表和数量的命令行如下所示：

gcloud compute instances list

或

GET https://compute.googleapis.com/compute/v1/projects/{project}/zones/{zone}/instances

如何使用 Google Cloud 在 Python 中获得等效功能？

Answer 1

此处有相关文档：https://cloud.google.com/compute/docs/tutorials/python-guide

简而言之：

import googleapiclient.discovery

project="your project"
zone="your zone"

compute = googleapiclient.discovery.build('compute', 'v1')
instances = compute.instances().list(project=project, zone=zone).execute()

for instance in instances:
    print(' - ' + instance['name'])

Answer 2

下面是我编写的一个示例，它使用 REST API 而没有使用 Google Cloud SDK 之一。

此示例将向您介绍服务帐户、授权、访问令牌和 Compute Engine REST 的底层详细信息API。

'''
This program lists lists the Google Compute Engine Instances in one zone
'''

import time
import json
import jwt
import requests
import httplib2

# Project ID for this request.
project = 'development-123456'

# The name of the zone for this request.
zone = 'us-west1-a'

# Service Account Credentials, Json format
json_filename = 'service-account.json'

# Permissions to request for Access Token
scopes = "https://www.googleapis.com/auth/cloud-platform"

# Set how long this token will be valid in seconds
expires_in = 3600   # Expires in 1 hour

def load_json_credentials(filename):
    ''' Load the Google Service Account Credentials from Json file '''

    with open(filename, 'r') as f:
        data = f.read()

    return json.loads(data)

def load_private_key(json_cred):
    ''' Return the private key from the json credentials '''

    return json_cred['private_key']

def create_signed_jwt(pkey, pkey_id, email, scope):
    '''
    Create a Signed JWT from a service account Json credentials file
    This Signed JWT will later be exchanged for an Access Token
    '''

    # Google Endpoint for creating OAuth 2.0 Access Tokens from Signed-JWT
    auth_url = "https://www.googleapis.com/oauth2/v4/token"

    issued = int(time.time())
    expires = issued + expires_in   # expires_in is in seconds

    # Note: this token expires and cannot be refreshed. The token must be recreated

    # JWT Headers
    additional_headers = {
            'kid': pkey_id,
            "alg": "RS256",
            "typ": "JWT"    # Google uses SHA256withRSA
    }

    # JWT Payload
    payload = {
        "iss": email,       # Issuer claim
        "sub": email,       # Issuer claim
        "aud": auth_url,    # Audience claim
        "iat": issued,      # Issued At claim
        "exp": expires,     # Expire time
        "scope": scope      # Permissions
    }

    # Encode the headers and payload and sign creating a Signed JWT (JWS)
    sig = jwt.encode(payload, pkey, algorithm="RS256", headers=additional_headers)

    return sig

def exchangeJwtForAccessToken(signed_jwt):
    '''
    This function takes a Signed JWT and exchanges it for a Google OAuth Access Token
    '''

    auth_url = "https://www.googleapis.com/oauth2/v4/token"

    params = {
        "grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
        "assertion": signed_jwt
    }

    r = requests.post(auth_url, data=params)

    if r.ok:
        return(r.json()['access_token'], '')

    return None, r.text

def gce_list_instances(accessToken):
    '''
    This functions lists the Google Compute Engine Instances in one zone
    '''

    # Endpoint that we will call
    url = "https://www.googleapis.com/compute/v1/projects/" + project + "/zones/" + zone + "/instances"

    # One of the headers is "Authorization: Bearer $TOKEN"
    headers = {
        "Host": "www.googleapis.com",
        "Authorization": "Bearer " + accessToken,
        "Content-Type": "application/json"
    }

    h = httplib2.Http()

    resp, content = h.request(uri=url, method="GET", headers=headers)

    status = int(resp.status)

    if status < 200 or status >= 300:
        print('Error: HTTP Request failed')
        return

    j = json.loads(content.decode('utf-8').replace('\n', ''))

    print('Compute instances in zone', zone)
    print('------------------------------------------------------------')
    for item in j['items']:
        print(item['name'])

if __name__ == '__main__':
    cred = load_json_credentials(json_filename)

    private_key = load_private_key(cred)

    s_jwt = create_signed_jwt(
            private_key,
            cred['private_key_id'],
            cred['client_email'],
            scopes)

    token, err = exchangeJwtForAccessToken(s_jwt)

    if token is None:
        print('Error:', err)
        exit(1)

    gce_list_instances(token)