I have an Google Analytics Account that I want to automate some custom reports from, but I have some problems understanding what kind of Credentials I need. Most of the tutorials I have seen says I need to use OAuth client ID but the google developers console site says I need a Servide Account key.
What is the difference between the two? Using another Analytics Account I tried to setup a OAuth connection, and it worked, but I now got unsure about what kind of key I should use.
What I want to do is to just have a Python script set up to run at some times, and then to get the data I want to query for. The data is just the same as the one I can get from logging into the Google Analytics UI, so there is no need for any users to consent to giving me access to any personal data or what ever else the Consent form should be used for.
Can someone explain what the difference is between the two Credentials and what one would be the correct one to use for my project?
Both Service accounts and OAuth2 are used to access private user data. Private data is data that is accessible only by logging in. My posts on Google+ are public anyone can see them. The information in my Google Analytics is private owned by me only I can see it and those I grant access to it.
With Oauth2 access is granted at run time. The first time an application is run the user will be asked if your application can access their data. If the user accepts and grants your application access you will be given a refresh token. This refresh token can be then used to get an access token which is used to access the private user data. Access tokens are only good for about an hour. After the hour is up you use the refresh token to get access again. That's why I say access is granted at runtime. You only have to ask the user for access once to get the refresh token though.
Service accounts on the other hand are pre authenticated. Service accounts are like dummy users they have their own google drive account and google calendar account. Because if this it is possible to shire data with them like you would any other user. You take the service account email address and add it as a user under the admin section of google analytics at the ACCOUNT level it must be the ACCOUNT level. Then using the service account in your code, you will be able to access the data for that Google Analytics account without requesting authentication from a user the first time.
Service accounts are most often used by developers to grant others access to the data owned by the developer. Oauth2 on the other hand would be used to access data of your customers for whos accounts you the developer does not personally have access to.
Technically speaking you can use either for your project as long as you store the refresh token you could technically use Oauth2 for your project. However I would not recommend it refresh tokens can expire under certain circumstances, which I will not go into.
I would recommend using a service account in your case it will be much easer for you to administrate as you will only need to set it up once.
My tutorials on the subject: