Specs

fetch(map()) :: {:ok, t()} | {:error, Exception.t()}

Fetch the token from the Google API using the given config.

Config may contain the following keys:

• :source - See "Source" section below.

• :http_client - HTTP client configuration, defaults to using Goth.HTTPClient.Hackney. See Goth.HTTPClient for more information.

Source

Source can be one of:

Service account - {:service_account, credentials, options}

The credentials is a map and can contain the following keys:

• "private_key"

• "client_email"

The options is a keywords list and can contain the following keys:

• :url - the URL of the authentication service, defaults to: "https://www.googleapis.com/oauth2/v4/token"

• :scopes - the list of token scopes, defaults to ["https://www.googleapis.com/auth/cloud-platform"]

• :sub - an email of user being impersonated, defaults to nil

Refresh token - {:refresh_token, credentials, options}

The credentials is a map and can contain the following keys:

• "refresh_token"

• "client_id"

• "client_secret"

The options is a keywords list and can contain the following keys:

• :url - the URL of the authentication service, defaults to: "https://www.googleapis.com/oauth2/v4/token"

Google metadata server - {:metadata, options}

The options is a keywords list and can contain the following keys:

• :account - the name of the account to generate the token for, defaults to "default"

• :url - the URL of the metadata server, defaults to "http://metadata.google.internal"

Examples

Generate a token using a service account credentials file:

iex> credentials = "credentials.json" |> File.read!() |> Jason.decode!()
iex> Goth.Token.fetch(%{source: {:service_account, credentials, []}})
{:ok, %Goth.Token{...}}

You can generate a credentials file containing service account using gcloud utility like this:

gcloud iam service-accounts keys create --key-file-type=json --iam-account=... credentials.json

Retrieve the token using a refresh token:

iex> credentials = "credentials.json" |> File.read!() |> Jason.decode!()
iex> Goth.Token.fetch(%{source: {:refresh_token, credentials, []}})
{:ok, %Goth.Token{...}}

You can generate a credentials file containing refresh token using gcloud utility like this:

gcloud auth application-default login

Retrieve the token using the Google metadata server:

iex> Goth.Token.fetch(%{source: {:metadata, []}})
{:ok, %Goth.Token{...}}

See Storing and retrieving instance metadata for more information on metadata server.

Specs

for_scope(scope :: String.t(), sub :: String.t() | nil) ::
  {:ok, t()} | {:error, any()}

for_scope(info :: {String.t() | atom(), String.t()}, sub :: String.t() | nil) ::
  {:ok, t()} | {:error, any()}