Google + Auth = GoogleAuth
A simple library to generate and retrieve OAuth2 tokens for use with Google Cloud Service accounts.
It can either retrieve tokens using service account credentials or from Google's metadata service for applications running on Google Cloud Platform.
- Add GoogleAuth to your list of dependencies in
mix.exs:
def deps do
[{:google_auth, "~> 1.1.0"}]
end- Pass in your credentials json downloaded from your GCE account:
config :google_auth,
json: "path/to/google/json/creds.json" |> File.read!Or, via an ENV var:
config :google_auth, json: {:system, "GCP_CREDENTIALS"}Or, via your own config module:
config :google_auth, config_module: MyConfigModdefmodule MyConfigMod do
use GoogleAuth.Config
def init(config) do
{:ok, Keyword.put(config, :json, System.get_env("MY_GCP_JSON_CREDENTIALS"))}
end
endYou can also use a JSON file containing an array of service accounts to be able to use different identities in your application. Each service
account will be identified by its client_email, which can be passed to GoogleAuth.Token.for_scope/1 to specify which service account to use.
For example, if your JSON file contains the following:
[
{
"client_email": "account1@myproject.iam.gserviceaccount.com",
...
},
{
"client_email": "account2@myproject.iam.gserviceaccount.com",
...
}
]You can use the following to get a token for the second service account:
def get_token do
{:ok, token} = GoogleAuth.Token.for_scope({
"account2@myproject.iam.gserviceaccount.com",
"https://www.googleapis.com/auth/cloud-platform.read-only"})
endYou can skip the last step if your application will run on a GCP or GKE instance with appropriate permissions.
If you need to set the email account to impersonate. For example when using service accounts
config :google_auth,
json: {:system, "GCP_CREDENTIALS"},
actor_email: "some-email@your-domain.com"Alternatively, you can pass your sub email on a per-call basis, for example:
GoogleAuth.Token.for_scope("https://www.googleapis.com/auth/pubsub",
"some-email@your-domain.com")If you need to disable GoogleAuth in certain environments, you can set a disabled
flag in your config:
config :google_auth,
disabled: trueThis initializes GoogleAuth with an empty config, so any attempts to actually generate tokens will fail.
Call Token.for_scope/1 passing in a string of scopes, separated by a space:
alias GoogleAuth.Token
{:ok, token} = Token.for_scope("https://www.googleapis.com/auth/pubsub")
#=>
%GoogleAuth.Token{
expires: 1453356568,
token: "ya29.cALlJ4ICWRvMkYB-WsAR-CZnExE459PA7QPqKg5nei9y2T9-iqmbcgxq8XrTATNn_BPim",
type: "Bearer"
}