I built a rest api using flask restplus and I tested it using the swagger documentation, and it seems to be fully functional and working just fine. I now want to test the API using the python requests library, but I'm getting the following error:
Invalid IAP credentials: empty token
I imagine this is because I did not authorize using the credentials. I do have access to the service account credentials json file, but just wondering how I pass this into requests?
Code Example:
url = 'https://crosssellapi-project-id.appspot.com/auth/login'
r = requests.get(url, headers={'accept': 'application/json'})
Thanks in advance.
I think the best way to accomplish this is using the google-auth library for python.
$ pip install google-auth
I suggest to create a service account, give it the role IAP-secured Web App User and then download the JSON key for that service account.
Go to API's & Services > Credentials and copy the Client ID of the OAuth 2.0 client you want to use for your API.
Finally use this code snippet to make a request:
from google.oauth2 import service_account
from google.auth.transport.requests import AuthorizedSession
SERVICE_FILENAME = '/path/to/your/service_account_key.json'
API_URL = 'https://YOUR_API_URL'
AUDIENCE = 'YOUR_OAUTH_CLIENT_ID'
credentials = service_account.IDTokenCredentials.from_service_account_file(SERVICE_FILENAME, target_audience=AUDIENCE)
session = AuthorizedSession(credentials)
r = session.get(API_URL, headers={'accept': 'application/json'})
print(r.text)
If you want to know more about google-auth check this.
I cant use OAuth2 authentication for accessing Google cloud print as I can't have a browser redirection for account selection. So I am trying out Google service account for accessing Google cloud print (suggested method for these scenarios). But under the googleapiclient.discovery , I am unable to find a key word for cloud printing. This is the code snippet which I tried.
from google.oauth2 import service_account
import requests
SCOPES = ['https://www.googleapis.com/auth/cloudprint']
SERVICE_ACCOUNT_FILE = 'secret.json'
credentials = service_account.Credentials.from_service_account_file(
SERVICE_ACCOUNT_FILE, scopes=SCOPES)
sqladmin = googleapiclient.discovery.build('sqladmin', 'v1beta3', credentials=credentials)
I am confused at 2 places in the above code snippet.
1. If the scope provided is valid
2. What is the alternative for argument sqladmin in googleapiclient.discovery.build() function for Google cloud print.
gcloud auth print-access-token gives me a Bearer token that I can use later on; however, this is a shell command. How would I obtain one programmatically via the Google Cloud Python API?
I see a prior example using oauth2client, but oauth2client is now deprecated. How would I do this with google.auth and oauthlib?
While the above answer is quite informative, it misses one important point - credentials object obtained from google.auth.default() or compute_engine.Credentials() will not have token in it. So back to the original question of what is the programmatic alternative to gcloud auth print-access-token, my answer would be:
import google.auth
import google.auth.transport.requests
creds, project = google.auth.default()
# creds.valid is False, and creds.token is None
# Need to refresh credentials to populate those
auth_req = google.auth.transport.requests.Request()
creds.refresh(auth_req)
# Now you can use creds.token
I'm using the official google-auth package and default credentials, which will get you going both in local dev and on remote GCE/GKE app.
Too bad this is not properly documented and I had to read google-auth code to figure our how to obtain the token.
The answer depends on your environment and how you want to create / obtain credentials.
What are Google Cloud Credentials?
Google Cloud credentials are an OAuth 2.0 token. This token has at a minimum an Access Token and optionally a Refresh Token, Client ID Token, and supporting parameters such as expiration, Service Account Email or Client Email, etc.
The important item in Google Cloud APIs is the Access Token. This token is what authorizes access to the cloud. This token can be used in programs such as curl, software such as python, etc and does not require an SDK. The Access Token is used in the HTTP Authorization header.
What is an Access Token?
An access token is an opaque value generated by Google that is derived from a Signed JWT, more correctly called JWS. A JWT consists of a header and claims (the payload) Json structures. These two Json structures are signed with the Service Account's Private Key. These values are base64 encoded and concatenated to create the Access Key.
The format of an Access Token is: base64(header) + '.' + base64(payload) + '.' + base64(signature).
Here is an example JWT:
Header:
{
"alg": "RS256",
"typ": "JWT",
"kid": "42ba1e234ac91ffca687a5b5b3d0ca2d7ce0fc0a"
}
Payload:
{
"iss": "myservice#myproject.iam.gserviceaccount.com",
"iat": 1493833746,
"aud": "myservice.appspot.com",
"exp": 1493837346,
"sub": "myservice#myproject.iam.gserviceaccount.com"
}
Using an Access Token:
Example that will start a VM instance. Replace PROJECT_ID, ZONE and INSTANCE_NAME. This example is for Windows.
curl -v -X GET -H "Authorization: Bearer <access_token_here>" ^
https://www.googleapis.com/compute/v1/projects/%PROJECT_ID%/zones/%ZONE%/instances/%INSTANCE_NAME%/start
Compute Engine Service Account:
Dustin's answer is correct for this case, but I will include for completeness with some additional information.
These credentials are automatically created for you by GCP and are obtained from the VM Instance metadata. Permissions are controlled by Cloud API access scopes in the Google Console.
However, these credentials have some limitations. To modify the credentials you must stop the VM Instance first. Additionally, not all permissions (roles) are supported.
from google.auth import compute_engine
cred = compute_engine.Credentials()
Service Account Credentials:
Until you understand all of the types of credentials and their use cases, these are the credentials that you will use for everything except for gcloud and gsutil. Understanding these credentials will make working with Google Cloud much simpler when writing programs. Obtaining credentials from a Google Service Account Json file is easy. The only item to make note of is that credentials expire (typically 60 minutes) and either need to be refreshed or recreated.
gcloud auth print-access-token is NOT recommended. Service Account Credentials are the recommended method by Google.
These credentials are created by the Console, gcloud or via programs / APIs. Permissions are assigned to the creditials by IAM and function inside Compute Engine, App Engine, Firestore, Kubernetes, etc. as well as other environments outside of Google Cloud. These credentials are downloaded from Google Cloud and stored in a Json file. Notice the scopes parameter. This defines permissions that are granted to the resulting credentials object.
SCOPES = ['https://www.googleapis.com/auth/sqlservice.admin']
SERVICE_ACCOUNT_FILE = 'service-account-credentials.json'
from google.oauth2 import service_account
cred = service_account.Credentials.from_service_account_file(
SERVICE_ACCOUNT_FILE, scopes=SCOPES)
Google OAuth 2.0 Credentials:
These credentials are derived from a full OAuth 2.0 flow. These credentials are generated when your browser is launched to access Google Accounts for authorizing access. This process is much more complicated and requires a fair amount of code to implement and requires a built-in web server for the callback for authorization.
This method provides additional features such as being able to run everything in a browser, example you can create a Cloud Storage File Browser, but be careful that you understand the security implications. This method is the technique used to support Google Sign-In, etc. I like to use this method to authenticate users before allowing posting on websites, etc. The possibilities are endless with correctly authorized OAuth 2.0 identities and scopes.
Example code using google_auth_oauthlib:
from google_auth_oauthlib.flow import InstalledAppFlow
flow = InstalledAppFlow.from_client_secrets_file(
'client_secrets.json',
scopes=scope)
cred = flow.run_local_server(
host='localhost',
port=8088,
authorization_prompt_message='Please visit this URL: {url}',
success_message='The auth flow is complete; you may close this window.',
open_browser=True)
Example code using the requests_oauthlib library:
from requests_oauthlib import OAuth2Session
gcp = OAuth2Session(
app.config['gcp_client_id'],
scope=scope,
redirect_uri=redirect_uri)
# print('Requesting authorization url:', authorization_base_url)
authorization_url, state = gcp.authorization_url(
authorization_base_url,
access_type="offline",
prompt="consent",
include_granted_scopes='true')
session['oauth_state'] = state
return redirect(authorization_url)
# Next section of code after the browser approves the request
token = gcp.fetch_token(
token_url,
client_secret=app.config['gcp_client_secret'],
authorization_response=request.url)
In some cases, it's not possible to set environment variables on the server or container while needing a Bearer access token to call Google cloud APIs. I present the following to solve such problem:
# pip3 install google-auth
# pip3 install requests
import google.auth
import google.auth.transport.requests
from google.oauth2 import service_account
credentials = service_account.Credentials.from_service_account_file('/home/user/secrets/hil-test.json', scopes=['https://www.googleapis.com/auth/cloud-platform'])
auth_req = google.auth.transport.requests.Request()
credentials.refresh(auth_req)
credentials.token
The last line would print the access token for calling Google cloud APIs. Replace ya29<REDACTED> in the following curl command with the printed token from python as a test:
curl https://example.googleapis.com/v1alpha1/projects/PROJECT_ID/locations -H "Authorization: Bearer ya29<REDACTED>"
It may not make sense to execute python to get the token then curl in BASH to call an API. The purpose is to demonstrate getting the token to call Google cloud Alpha API which may not have any Python client library but REST API. Developers can then use Python requests HTTP library to call the APIs.
import google.auth
import google.auth.transport.requests
# getting the credentials and project details for gcp project
credentials, your_project_id = google.auth.default(scopes=["https://www.googleapis.com/auth/cloud-platform"])
#getting request object
auth_req = google.auth.transport.requests.Request()
print(credentials.valid) # prints False
credentials.refresh(auth_req) #refresh token
#cehck for valid credentials
print(credentials.valid) # prints True
print(credentials.token) # prints token
This may not be the recommended way but for Rest API in my application this was an easy way to get the token.
from subprocess import PIPE, Popen
def cmdline(command):
process = Popen(
args=command,
stdout=PIPE,
shell=True
)
return process.communicate()[0]
token = cmdline("gcloud auth application-default print-access-token")
print("Token:"+token)
I found myself here when looking for a way to use the python SDK without creating a service account. I wanted a way to locally develop a script that would run in the cloud. I was able to achieve this by using an artifact of the gcloud command:
export GOOGLE_APPLICATION_CREDENTIALS=~/.config/gcloud/legacy_credentials/<me>/adc.json
Merging suggestions from this post and the google cloud documentation, I wrote an auxiliary function that returns a token. It generates a token if possible, and if not takes it from the environment, then checks that it's valid.
import google
import os
import requests
GOOGLE_APPLICATION_CREDENTIALS = "GOOGLE_APPLICATION_CREDENTIALS"
GCS_OAUTH_TOKEN = "GCS_OAUTH_TOKEN"
SCOPE = "https://www.googleapis.com/auth/cloud-platform"
URL = "https://www.googleapis.com/oauth2/v1/tokeninfo"
PAYLOAD = "access_token={}"
HEADERS = {"content-type": "application/x-www-form-urlencoded"}
OK = "OK"
def get_gcs_token():
"""
Returns gcs access token.
Ideally, this function generates a new token, requries that GOOGLE_APPLICATION_CREDENTIALS be set in the environment
(os.environ).
Alternatively, environment variable GCS_OAUTH_TOKEN could be set if a token already exists
"""
if GOOGLE_APPLICATION_CREDENTIALS in os.environ:
# getting the credentials and project details for gcp project
credentials, your_project_id = google.auth.default(scopes=[SCOPE])
# getting request object
auth_req = google.auth.transport.requests.Request()
credentials.refresh(auth_req) # refresh token
token = credentials.token
elif GCS_OAUTH_TOKEN in os.environ:
token = os.environ[GCS_OAUTH_TOKEN]
else:
raise ValueError(
f"""Could not generate gcs token because {GOOGLE_APPLICATION_CREDENTIALS} is not set in the environment.
Alternatively, environment variable {GCS_OAUTH_TOKEN} could be set if a token already exists, but it was not"""
)
r = requests.post(URL, data=PAYLOAD.format(token), headers=HEADERS)
if not r.reason == OK:
raise ValueError(
f"Could not verify token {token}\n\nResponse from server:\n{r.text}"
)
if not r.json()["expires_in"] > 0:
raise ValueError(f"token {token} expired")
return token
Official documentation code example
I followed this official documentation for Cloud Functions, which works for any GCP API:
auth_req = google.auth.transport.requests.Request()
id_token = google.oauth2.id_token.fetch_id_token(
auth_req,
# This is an OAuth authorisation scope that you must pass
# depending on the API.
# You can see an example of the need for this scope here: https://cloud.google.com/bigquery/docs/reference/rest/v2/jobs/insert#authorization-scopes
"https://www.googleapis.com/auth/bigquery"
)
Now, you can use id_token in the Authorisation header:
headers = {'Authorization': f'Bearer {id_token}'}
I'm using the python google.cloud api
For example using the metrics module
from google.cloud import monitoring
client = monitoring.Client()
client.query(my/gcp/metric, minutes=10)
For my GOOGLE_APPLICATION_CREDENTIALS im using a service account that has specific access to a gcp project.
Does google.cloud have any modules that can let me derive the project from the service account (like get what project the service account is in)?
This would be convenient because each service account only has access to a single project, so I could set my service account and be able to reference that project in code.
Not sure if this will work, you may need to tweak it:
from googleapiclient import discovery
from oauth2client.client import GoogleCredentials
credentials = GoogleCredentials.get_application_default()
service = discovery.build('yourservicename', credentials=credentials)
request = service.projects().list()[0]
Google Cloud Identity and Access Management (IAM) API has ‘serviceAccounts.get’ method and which shows the projects associated with a service account as shown here. You need to have proper permissions on the projects for the API to work.
The method google.auth.default return a tuple (project_id, credentials) if that information is available on the environment.
Also, the client object knows to which project it is linked from (either client.project or client.project_id, I'm not sure which one for the Monitoring API).
If you set the service account manually with the GOOGLE_APPLICATION_CREDENTIALS env var, you can open the file and load its json. One of the parameters in a service account key file is the project id.
This is a follow-up question for this question:
I have successfully created a private key and have read the various pages of Google documentation on the concepts of server to server authentication.
I need to create a JWT to authorize my App Engine application (Python) to access the Google calendar and post events in the calendar. From the source in oauth2client it looks like I need to use oauth2client.client.SignedJwtAssertionCredentials to create the JWT.
What I'm missing at the moment is a stylised bit of sample Python code of the various steps involved to create the JWT and use it to authenticate my App Engine application for Google Calendar. Also, from SignedJwtAssertionCredentials source it looks like I need some App Engine compatible library to perform the signing.
Can anybody shed some light on this?
After some digging I found a couple of samples based on the OAuth2 authentication. From this I cooked up the following simple sample that creates a JWT to access the calendar API:
import httplib2
import pprint
from apiclient.discovery import build
from oauth2client.client import SignedJwtAssertionCredentials
# Get the private key from the Google supplied private key file.
f = file("your_private_key_file.p12", "rb")
key = f.read()
f.close()
# Create the JWT
credentials = SignedJwtAssertionCredentials(
"xxxxxxxxxx#developer.gserviceaccount.com", key,
scope="https://www.googleapis.com/auth/calendar"
)
# Create an authorized http instance
http = httplib2.Http()
http = credentials.authorize(http)
# Create a service call to the calendar API
service = build("calendar", "v3", http=http)
# List all calendars.
lists = service.calendarList().list(pageToken=None).execute(http=http)
pprint.pprint(lists)
For this to work on Google App Engine you will need to enable PyCrypto for your app. This means adding the following to your app.yaml file:
libraries:
- name: pycrypto
version: "latest"