[英]Running a python script on Google Cloud Compute Engine
[英]How to get number of compute engine instances running on Google Cloud
在 Google Cloud 文檔中,獲取在 Google Cloud 中的項目上運行的實例列表和數量的命令行如下所示:
gcloud compute instances list
或者
GET https://compute.googleapis.com/compute/v1/projects/{project}/zones/{zone}/instances
如何使用 Google Cloud 在 Python 中獲得等效的 function?
這里有關於此的文檔: https://cloud.google.com/compute/docs/tutorials/python-guide
簡而言之:
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'])
下面是我編寫的一個示例,它使用 REST API 並且不使用 Google Cloud SDK 之一。
此示例將教您服務帳戶、授權、訪問令牌和 Compute Engine REST API 的低級詳細信息。
'''
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)
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