Add support for authentication with Earthdata login token only

CHANGELOG.md

@@ -39,6 +39,10 @@ and this project uses [Semantic Versioning](https://semver.org/spec/v2.0.0.html)
 - `download` now returns Path consistently.
   ([#595])(https://github.com/nsidc/earthaccess/issues/595)
   ([@Sherwin-14](https://github.com/Sherwin-14))
+- Users may now authenticate with an existing Earthdata login token with
+  environment variable `EARTHDATA_TOKEN`
+  ([#484](https://github.com/nsidc/earthaccess/issues/484))
+  ([@kgrimes2](https://github.com/kgrimes2))
 
 ### Removed
 

docs/howto/authenticate.md

@@ -31,6 +31,9 @@ use:
 auth = earthaccess.login(strategy="environment")
 ```
 
+Alternatively, you can use an existing Earthdata Login token by setting the environment
+variable `EARTHDATA_TOKEN` to it and using the same "environment" strategy, above.
+
 If you wish to enter your Earthdata Login credentials when prompted, with
 optional persistence to your `.netrc` file (see below), specify the interactive
 strategy:
@@ -54,7 +57,8 @@ credentials in two locations:
    used throughout documentation primarily for convenience.  The only
    requirement is that the *contents* of the file adhere to the
    [`.netrc` file format](https://www.gnu.org/software/inetutils/manual/html_node/The-_002enetrc-file.html).
-2. `EARTHDATA_USERNAME` and `EARTHDATA_PASSWORD` environment variables
+2. `EARTHDATA_USERNAME` and `EARTHDATA_PASSWORD` environment variables (or, optionally, `EARTHDATA_TOKEN`
+   to use an existing Earthdata Login token)
 
 If neither of these options are configured, you can authenticate by calling the
 `earthaccess.login()` method and manually entering your EDL account credentials.

earthaccess/api.py

@@ -184,7 +184,9 @@ def login(
             * **"all"**: (default) try all methods until one works
             * **"interactive"**: enter username and password.
             * **"netrc"**: retrieve username and password from ~/.netrc.
-            * **"environment"**: retrieve username and password from `$EARTHDATA_USERNAME` and `$EARTHDATA_PASSWORD`.
+            * **"environment"**: retrieve either a username and password pair from
+              the `EARTHDATA_USERNAME` and `EARTHDATA_PASSWORD` environment variables,
+              or an Earthdata login token from the `EARTHDATA_TOKEN` environment variable.
         persist: will persist credentials in a .netrc file
         system: the Earthdata system to access, defaults to PROD
 

earthaccess/auth.py

@@ -110,8 +110,11 @@ def login(
                 * **"interactive"**: Enter a username and password.
                 * **"netrc"**: (default) Retrieve a username and password from ~/.netrc.
                 * **"environment"**:
-                    Retrieve a username and password from $EARTHDATA_USERNAME and $EARTHDATA_PASSWORD.
-            persist: Will persist credentials in a `.netrc` file.
+                    Retrieve either a username and password pair from the
+                    `EARTHDATA_USERNAME` and `EARTHDATA_PASSWORD` environment variables,
+                    or an Earthdata login token from the `EARTHDATA_TOKEN` environment
+                    variable.
+            persist: Will persist username and password credentials in a `.netrc` file.
             system: the EDL endpoint to log in to Earthdata, defaults to PROD
 
         Returns:
@@ -245,7 +248,7 @@ def _interactive(
     ) -> bool:
         username = input("Enter your Earthdata Login username: ")
         password = getpass.getpass(prompt="Enter your Earthdata password: ")
-        authenticated = self._get_credentials(username, password)
+        authenticated = self._get_credentials(username, password, None)
         if authenticated:
             logger.debug("Using user provided credentials for EDL")
             if persist_credentials:
@@ -282,7 +285,7 @@ def _netrc(self) -> bool:
                 f"Password not found in .netrc file {netrc_loc}"
             )
 
-        authenticated = self._get_credentials(username, password)
+        authenticated = self._get_credentials(username, password, None)
 
         if authenticated:
             logger.debug("Using .netrc file for EDL")
@@ -292,21 +295,27 @@ def _netrc(self) -> bool:
     def _environment(self) -> bool:
         username = os.getenv("EARTHDATA_USERNAME")
         password = os.getenv("EARTHDATA_PASSWORD")
+        token = os.getenv("EARTHDATA_TOKEN")
 
-        if not username or not password:
+        if (not username or not password) and not token:
             raise LoginStrategyUnavailable(
-                "EARTHDATA_USERNAME and EARTHDATA_PASSWORD are not set in the current environment, try "
-                "setting them or use a different strategy (netrc, interactive)"
+                "Either the environment variables EARTHDATA_USERNAME and "
+                "EARTHDATA_PASSWORD must both be set, or EARTHDATA_TOKEN must be set for "
+                "the 'environment' login strategy."
             )
 
         logger.debug("Using environment variables for EDL")
-        return self._get_credentials(username, password)
+        return self._get_credentials(username, password, token)
 
     def _get_credentials(
         self,
         username: Optional[str],
         password: Optional[str],
+        user_token: Optional[str],
     ) -> bool:
+        if user_token is not None:
+            self.token = {"access_token": user_token}
+            self.authenticated = True
         if username is not None and password is not None:
             token_resp = self._find_or_create_token(username, password)
 

tests/unit/test_auth.py

@@ -1,5 +1,6 @@
 # package imports
 import logging
+import os
 import unittest
 from unittest import mock
 
@@ -74,6 +75,18 @@ def test_auth_can_create_proper_credentials(self, user_input, user_password):
         self.assertEqual(auth.password, "password")
         self.assertEqual(auth.token, json_response)
 
+    @responses.activate
+    def test_auth_can_parse_existing_user_token(self):
+        user_token = "ABCDEFGHIJKLMNOPQ"
+        os.environ["EARTHDATA_TOKEN"] = user_token
+        json_response = {"access_token": user_token}
+
+        # Test
+        auth = Auth()
+        auth.login(strategy="environment")
+        self.assertEqual(auth.authenticated, True)
+        self.assertEqual(auth.token, json_response)
+
     @responses.activate
     @mock.patch("getpass.getpass")
     @mock.patch("builtins.input")