How to get a GCP identity-token programmatically with python - python

What is the python programmatic alternative to the gcloud command line gcloud auth print-identity-token?
I am trying to invoke Google Cloud Function by http trigger (only for auth users) and i need to pass the identity token in the Authentication header. I have method which works great when i run the code on GCP app engine. However, i struggle to find a way to get this identity token when i run the program on my own machine (where i can create the token with gcloud command line gcloud auth print-identity-token)
I found how to create access-token according to this answer but i didn't managed to understand how can i create identity-token.
Thank you in advance!

Great topic! And it's a long long way, and months of tests and discussion with Google.
TL;DR: you can't generate an identity token with your user credential, you need to have a service account (or to impersonate a service) to generate an identity token.
If you have a service account key file, I can share a piece of code to generate an identity token, but generating and having a service account key file is globally a bad practice.
I released an article on this and 2 merge requests to implement an evolution in the Java Google auth library (I'm more Java developer that python developer even if I also contribute to python OSS project) here and here. You can read them if you want to understand what is missing and how works the gcloud command today.
On the latest merge request, I understood that something is coming from google, internally, but up to now, I didn't see anything...

If you have a service account you can impersonate this is one way to get an ID token in Python from a local/dev machine.
import google.auth
from google.auth.transport.requests import AuthorizedSession
def impersonated_id_token():
credentials, project = google.auth.default(scopes=['https://www.googleapis.com/auth/cloud-platform'])
authed_session = AuthorizedSession(credentials)
sa_to_impersonate = "<SA_NAME>#<GCP_PROJECT>.iam.gserviceaccount.com"
request_body = {"audience": "<SOME_URL>"}
response = authed_session.post( f'https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/{sa_to_impersonate}:generateIdToken',request_body)
return response
if __name__ == "__main__":
print(impersonated_id_token().json())

Related

Get access token from google.oauth2.Credentials

Currently, I am building the async frontend to my TF2 model. Now it works as two services, 1st service is a twisted service, and 2nd service is a TensorFlow serving.
The async web client is being used to query the model asynchronously. For practical reasons, I've deployed the model into the GCP AI Platform, and I can get data from it using the python code from examples, and it is okay.
But the thing is that the Google API client is synchronous, and I would like to use the asynchronous client. Since, AFAIK, there are no actively supported async clients for GCP, I tried to get straightforward and use REST. The model input is the same on TensorFlow serving (GCP AI Platform uses TensorFlow serving internally, I believe).
To perform the async call, I need to have:
Model URL. (I have it)
Input data. (I also have it)
Access token.
I saw some examples that are:
import googleapiclient.discovery
credentials = service_account.Credentials.from_service_account_file(
'/path/to/key.json',
scopes=['https://www.googleapis.com/auth/cloud-platform'])
But the issue is that credential.token is None, so I can't use it.
So I have a question: how could I get the access token to use in the rest request then?
Or maybe there is another but better way of doing that?
I already saw the following question: How to get access token from instance of google.oauth2.service_account.Credentials object?
but I am think that it is slightly irrelevant.
The following code sets up the data structures for managing credentials (OAuth tokens) from a service account. No tokens are requested at this point.
credentials = service_account.Credentials.from_service_account_file(
'/path/to/key.json',
scopes=['https://www.googleapis.com/auth/cloud-platform'])
Tokens are not requested from the Google auth server until required. There are several reasons: a) network calls take time - a significant amount of time for network failures; b) tokens expire; c) tokens are cached until they (almost) expire.
To generate a token, call the refresh() method:
import google.auth.transport.requests
request = google.auth.transport.requests.Request()
credentials.refresh(request)
credential.token will now contain an OAuth Access Token else an exception will be thrown (network error, etc.).
Just focusing on "How do I get an access token?", you will need to:
Create a Service Account
Use the Google Auth library
Run code
NOTE If you're running the code off-GCP (i.e. not on App Engine, Compute Engine, GKE etc.), then you will need to create a Key for the Service Account and you will need to export GOOGLE_APPLICATION_CREDENTIALS=path/to/your/key.json. Application Default Credentials (see below) simplify auth.
See: Authenticating as a Service Account
And:
import google.auth
from googleapiclient.discovery import build
SCOPES = ["https://www.googleapis.com/auth/cloud-platform"]
creds, project_id = google.auth.default(scopes=SCOPES)
service = build(GOOGLE_API, GOOGLE_API_VERSION, credentials=creds)

Can I check if a script is running inside a Compute Engine or in a local environment?

I just wanted to know if there is a way to check whether a Python script is running inside a Compute Engine or in a local environment?
I want to check that in order to know how to authenticate, for example when a script runs on a Compute Engine and I want to initiate a BigQuery client I do not need to authenticate but when it comes to running a script locally I need to authenticate using a service account JSON file.
If I knew whether a script is running locally or in a Compute Engine I would be able to initiate Google services accordingly.
I could put initialization into a try-except statement but maybe there is another way?
Any help is appreciated.
If I understand your question correctly, I think a better solution is provided by Google called Application Default Credentials. See Best practices to securely auth apps in Google Cloud (thanks #sethvargo) and Application Default Credentials
Using this mechanism, authentication becomes consistent regardless of where you run your app (on- or off-GCP). See finding credentials automatically
When you run off-GCP, you set GOOGLE_APPLICATION_CREDENTIALS to point to the Service Account. When you run on-GCP (and, to be clear, you are still authenticating, it's just transparent), you don't set the environment variable because the library obtains the e.g. Compute Engine instance's service account for you.
So I read a bit on the Google Cloud authentication and came up with this solution:
import google.auth
from google.oauth2 import service_account
try:
credentials, project = google.auth.default()
except:
credentials = service_account.Credentials.from_service_account_file('/path/to/service_account_json_file.json')
client = storage.Client(credentials=credentials)
What this does is it tries to retrieve the default Google Cloud credentials (in environments such as Compute Engine) and if it fails it tries to authenticate using a service account JSON file.
It might not be the best solution but it works and I hope it will help someone else too.

How can I grant a Cloud Run service access to service account's credentials without the key file?

I'm developing a Cloud Run Service that accesses different Google APIs using a service account's secrets file with the following python 3 code:
from google.oauth2 import service_account
credentials = service_account.Credentials.from_service_account_file(SECRETS_FILE_PATH, scopes=SCOPES)
In order to deploy it, I upload the secrets file during the build/deploy process (via gcloud builds submit and gcloud run deploy commands).
How can I avoid uploading the secrets file like this?
Edit 1:
I think it is important to note that I need to impersonate user accounts from GSuite/Workspace (with domain wide delegation). The way I deal with this is by using the above credentials followed by:
delegated_credentials = credentials.with_subject(USER_EMAIL)
Using the Secret Manager might help you, as you can manage the multiple secrets you have and not have them stored as files, as you are doing right now. I would recommend you to take a look at this article here, so you can get more information on how to use it with Cloud Run, to improve the way you manage your secrets.
In addition to that, as clarified in this similar case here, you have two options: use default service account that comes with it or deploy another one with the Service Admin role. This way, you won't need to specify keys with variables - as clarified by a Google developer in this specific answer.
To improve the security, the best way is to never use service account key file, locally or on GCP (I wrote an article on this). To achieve this, Google Cloud service have an automatically loaded service account, either this one by default or, when possible, a custom one.
On Cloud Run, the default service account is the Compute Engine default service account (I recommend you to never use it, it has editor role on the project, it's too wide!), or you can specify the service account to use (--service-account= parameter)
Then, in your code, simply use the ADC mechanism (Application Default Credential) to get your credentials, like this in Python
import google.auth
credentials, project_id = google.auth.default(scopes=SCOPES)
I've found one way to solve the problem.
First, as suggested by guillaume blaquiere answer, I used google.auth ADC mechanism:
import google.auth
credentials, project_id = google.auth.default(scopes=SCOPES)
However, as I need to impersonate GSuite's (now Workspace) accounts, this method is not enough, as the credentials object generated from this method does not have the with_subject property. This led me to this similar post and specific answer which works a way to convert google.auth.credentials into the Credential object returned by service_account.Credentials.from_service_account_file. There was one problem with his solution, as it seemed that an authentication scope was missing.
All I had to do is add the https://www.googleapis.com/auth/cloud-platform scope to the following places:
The SCOPES variable in the code
Google Admin > Security > API Controls > Set client ID and scope for the service account I am deploying with
At the OAuth Consent Screen of my project
After that, my Cloud Run had access to credentials that were able to impersonate user's accounts without using key files.

How to Create Python Code with Google API Client

I have code below that was given to me to list Google Cloud Service Accounts for a specific Project.
import os
from googleapiclient import discovery
from gcp import get_key
"""gets all Service Accounts from the Service Account page"""
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = get_key()
service = discovery.build('iam', 'v1')
project_id = 'projects/<google cloud project>'
request = service.projects().serviceAccounts().list(name=project_id)
response = request.execute()
accounts = response['accounts']
for account in accounts:
print(account['email'])
This code works perfectly and prints the accounts as I need them. What I'm trying to figure out is:
Where can I go to see how to construct code like this? I found a site that has references to the Python API Client, but I can't seem to figure out how to make the code above from it. I can see the Method to list the Service Accounts, but it's still not giving me enough information.
Is there somewhere else I should be going to educate myself. Any information you have is appreciated so I don't pull out the rest of my hair.
Thanks, Eric
Let me share with you this documentation page, where there is a detailed explanation on how to build a script such as the one you shared, and what does each line of code mean. It is extracted from the documentation of ML Engine, not IAM, but it is using the same Python Google API Client Libary, so just ignore the references to ML and the rest will be useful for you.
In any case, here it is a commented version of your code, so that you understand it better:
# Imports for the Client API Libraries and the key management
import os
from googleapiclient import discovery
from gcp import get_key
# Look for an environment variable containing the credentials for Google Cloud Platform
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = get_key()
# Build a Python representation of the REST API
service = discovery.build('iam', 'v1')
# Define the Project ID of your project
project_id = 'projects/<google cloud project>'
"""Until this point, the code is general to any API
From this point on, it is specific to the IAM API"""
# Create the request using the appropriate 'serviceAccounts' API
# You can substitute serviceAccounts by any other available API
request = service.projects().serviceAccounts().list(name=project_id)
# Execute the request that was built in the previous step
response = request.execute()
# Process the data from the response obtained with the request execution
accounts = response['accounts']
for account in accounts:
print(account['email'])
Once you understand the first part of the code, the last lines are specific to the API you are using, which in this case is the Google IAM API. In this link, you can find detailed information on the methods available and what they do.
Then, you can follow the Python API Client Library documentation that you shared in order to see how to call the methods. For instance, in the code you shared, the method used depends on service, which is the Python representation of the API, and then goes down the tree of methods in the last link as in projects(), then serviceAccounts() and finally the specificlist() method, which ends up in request = service.projects().serviceAccounts().list(name=project_id).
Finally, just in case you are interested in the other available APIs, please refer to this page for more information.
I hope the comments I made on your code were of help, and that the documentation shared makes it easier for you to understand how a code like that one could be scripted.
You can use ipython having googleapiclient installed - with something like:
sudo pip install --upgrade google-api-python-client
You can go to interactive python console and do:
from googleapiclient import discovery
dir(discovery)
help(discovery)
dir - gives all entries that object has - so:
a = ''
dir(a)
Will tell what you can do with string object. Doing help(a) will give help for string object. You can do dipper:
dir(discovery)
# and then for instance
help(discovery.re)
You can call your script in steps, and see what is result print it, do some research, having something - do %history to printout your session, and have solution that can be triggered as a script.

Using Google Calendar API v 3 with Python

Can someone please give me a clear explanation of how to get the Google Calendar API v3 working with the Python Client? Specifically, the initial OAuth stage is greatly confusing me. All I need to do is access my own calendar, read it, and make changes to it. Google provides this code for configuring my app:
import gflags
import httplib2
from apiclient.discovery import build
from oauth2client.file import Storage
from oauth2client.client import OAuth2WebServerFlow
from oauth2client.tools import run
FLAGS = gflags.FLAGS
# Set up a Flow object to be used if we need to authenticate. This
# sample uses OAuth 2.0, and we set up the OAuth2WebServerFlow with
# the information it needs to authenticate. Note that it is called
# the Web Server Flow, but it can also handle the flow for native
# applications
# The client_id and client_secret are copied from the API Access tab on
# the Google APIs Console
FLOW = OAuth2WebServerFlow(
client_id='YOUR_CLIENT_ID',
client_secret='YOUR_CLIENT_SECRET',
scope='https://www.googleapis.com/auth/calendar',
user_agent='YOUR_APPLICATION_NAME/YOUR_APPLICATION_VERSION')
# To disable the local server feature, uncomment the following line:
# FLAGS.auth_local_webserver = False
# If the Credentials don't exist or are invalid, run through the native client
# flow. The Storage object will ensure that if successful the good
# Credentials will get written back to a file.
storage = Storage('calendar.dat')
credentials = storage.get()
if credentials is None or credentials.invalid == True:
credentials = run(FLOW, storage)
# Create an httplib2.Http object to handle our HTTP requests and authorize it
# with our good Credentials.
http = httplib2.Http()
http = credentials.authorize(http)
# Build a service object for interacting with the API. Visit
# the Google APIs Console
# to get a developerKey for your own application.
service = build(serviceName='calendar', version='v3', http=http,
developerKey='YOUR_DEVELOPER_KEY')
But (a) it makes absolutely no sense to me; the comment explanations are terrible, and (b) I don't know what to put in the variables. I've registered my program with Google and signed up for a Service Account key. But all that gave me was an encrypted key file to download, and a client ID. I have no idea what a "developerKey" is, or what a "client_secret" is? Is that the key? If it is, how do I get it, since it is actually contained in an encrypted file? Finally, given the relatively simple goals of my API use (i.e., it's not a multi-user, multi-access operation), is there a simpler way to be doing this? Thanks.
A simple (read: way I've done it) way to do this is to create a web application instead of a service account. This may sound weird since you don't need any sort of web application, but I use this in the same way you do - make some queries to my own calendar/add events/etc. - all from the command line and without any sort of web-app interaction. There are ways to do it with a service account (I'll tinker around if you do in fact want to go on that route), but this has worked for me thus far.
After you create a web application, you will then have all of the information indicated above (side note: the sample code above is based on a web application - to use a service account your FLOW needs to call flow_from_clientsecrets and further adjustments need to be made - see here). Therefore you will be able to fill out this section:
FLOW = OAuth2WebServerFlow(
client_id='YOUR_CLIENT_ID',
client_secret='YOUR_CLIENT_SECRET',
scope='https://www.googleapis.com/auth/calendar',
user_agent='YOUR_APPLICATION_NAME/YOUR_APPLICATION_VERSION')
You can now fill out with the values you see in the API console (client_id = the entire Client ID string, client_secret = the client secret, scope is the same and the user_agent can be whatever you want). As for the service line, developerKey is the API key you can find under the Simple API Access section in the API console (label is API key):
service = build(serviceName='calendar', version='v3', http=http,
developerKey='<your_API_key>')
You can then add in a simple check like the following to see if it worked:
events = service.events().list(calendarId='<your_email_here>').execute()
print events
Now when you run this, a browser window will pop up that will allow you to complete the authentication flow. What this means is that all authentication will be handled by Google, and the authentication response info will be stored in calendar.dat. That file (which will be stored in the same directory as your script) will contain the authentication info that the service will now use. That is what is going here:
storage = Storage('calendar.dat')
credentials = storage.get()
if credentials is None or credentials.invalid == True:
credentials = run(FLOW, storage)
It checks for the existence of valid credentials by looking for that file and verifying the contents (this is all abstracted away from you to make it easier to implement). After you authenticate, the if statement will evaluate False and you will be able to access your data without needing to authenticate again.
Hopefully that shines a bit more light on the process - long story short, make a web application and use the parameters from that, authenticate once and then forget about it. I'm sure there are various points I'm overlooking, but hopefully it will work for your situation.
Google now has a good sample application that gets you up and running without too much fuss. It is available as the "5 minute experience - Quickstart" on their
Getting Started page.
It will give you a URL to visit directly if you are working on a remote server without a browser.

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