Introduction

As an example, we will explain how to operate the Compute Engine API with the API Client Library for Python. The flow should be similar for other languages and the Google Cloud API.

Assumed environment

Redhat Linux / MacOSX * For debian, the tool installation method should be slightly different.
Python 2.6, 2.7, 3.3, or 3.4 (as of September 2015) and pip have been installed
The verification environment used to write this article is as follows

$ cat /etc/redhat-release
CentOS Linux release 7.1.1503 (Core)
$ python -V
Python 2.7.5
$ pip -V
pip 7.1.0 from /usr/lib/python2.7/site-packages (python 2.7)

Preparation

Install API Client Library for Python.

$ sudo pip install --upgrade google-api-python-client

(Optional) Install the Google Cloud SDK.

$ sudo curl https://sdk.cloud.google.com | bash
→ All questions in the middle can be left with Y or the default value.
$ exec -l $SHELL

In your project's Google Developer Console, select "API and Authentication-API-API Library"-"Compute Engine API" and make sure the API is enabled (if disabled, enable the API " A button will appear, click it to enable it).

Authentication

I will explain two methods.

1. How to use a service account

How to create an application account instead of your google account. Of course, it is a mechanism for the application that you (they) use, so be careful not to distribute it to people.

In your project's Google Developer Console, select "Add Credentials-Service Account" from "APIs and Authentication-Credentials".
Specify "JSON" as the key type and select "Create".
The credential file will be downloaded with the name "project name-xxx.json", so save it in any path of the host that uses the API Client Library (* Handling precautions *).
Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the path of the credential file. If necessary, it is good to describe it in .bash_profile and others.

$ export GOOGLE_APPLICATION_CREDENTIALS='/xxx/xxx/Project name-xxx.json'

2. How to authenticate with gcloud command

How to authenticate with your google account and save your credentials on the host.

Execute the following command to set the authentication information on the host.

$ gcloud auth login
Go to the following link in your browser:

    https://accounts.google.com/o/oauth2/auth?redirect_uri=xxx...
→ Connect to the displayed URL with a web browser logged in with a google account that has access rights to your project.

Enter verification code:* Enter the authentication code displayed at the above URL
Saved Application Default Credentials.

Operation check

Save the sample code below.
Shebang line changed according to the environment
You can copy the 3rd to 6th lines.
From the 8th line onward, a sample that only acquires instance information using the Compute Engine API

`sample.py`


 1  #!/usr/bin/python
 2
 3  from oauth2client.client import GoogleCredentials
 4  from googleapiclient.discovery import build
 5
 6  credentials = GoogleCredentials.get_application_default()
 7  
 8  compute = build('compute', 'v1', credentials=credentials)
 9  project = 'Project ID'
10  zone = 'Zone name'
11  
12  print compute.instances().list(project=project, zone=zone).execute()

Execute and check the operation when the GCE instance information is displayed in a staggered manner.
I'm not afraid of anything when I get here. Just write a nice code while referring to the Reference as appropriate.

Digression and supplement

The gcloud command is sufficient for small operations, but sometimes you may want to do something nifty.
However, the OAuth authentication procedure required for that was troublesome to the extent that there were a certain number of people who gave up, but this story (http://googlecloudplatform-japan.blogspot.jp) /2015/07/application-default-credentials-google.html) I'm grateful that it has become much easier since then.
This content is as of September 2015. Since google related changes quickly, please do not rush to get the latest primary information even if something changes.

References https://cloud.google.com/compute/docs/tutorials/python-guide https://developers.google.com/api-client-library/python/?hl=ja

[Google Cloud Platform] Use Google Cloud API using API Client Library