Add --output option to pbench-generate-token

This option makes it a bit easier to script the invocation of
`pbench-generate-token` where username and/or password prompts are
required (the prompt does not get mixed up into the token output).

lib/pbench/cli/agent/commands/generate_token.py

@@ -38,7 +38,11 @@ def execute(self):
             payload = {"message": response.text}
 
         if response.ok and "auth_token" in payload:
-            click.echo(payload["auth_token"])
+            if not self.context.output:
+                click.echo(payload["auth_token"])
+            else:
+                with open(self.context.output, "w") as ofp:
+                    ofp.write(f"{payload['auth_token']}\n")
             return 0
 
         click.echo(
@@ -70,11 +74,17 @@ def execute(self):
     show_default=True,
     help="number of seconds",
 )
+@click.option(
+    "--output",
+    required=False,
+    help="Output file to which to write the generated token",
+)
 @pass_cli_context
-def main(context, username, password, token_duration):
+def main(context, username, password, token_duration, output):
     context.username = username
     context.password = password
     context.token_duration = token_duration
+    context.output = output
 
     try:
         rv = GenerateToken(context).execute()

lib/pbench/test/unit/agent/task/test_generate_token.py

@@ -1,4 +1,5 @@
 from http import HTTPStatus
+from pathlib import Path
 
 from click.testing import CliRunner
 import requests
@@ -11,6 +12,7 @@ class TestGenerateToken:
 
     USER_SWITCH = "--username"
     PSWD_SWITCH = "--password"
+    OUTPUT_SWITCH = "--output"
     USER_PROMPT = "Username: "
     PSWD_PROMPT = "Password: "
     USER_TEXT = "test_user"
@@ -37,6 +39,15 @@ def add_badlogin_mock_response():
             json={"message": "Bad login"},
         )
 
+    @staticmethod
+    def add_notjson_mock_response():
+        responses.add(
+            responses.POST,
+            TestGenerateToken.URL + TestGenerateToken.ENDPOINT,
+            status=HTTPStatus.FORBIDDEN,
+            body="NOT Jason",
+        )
+
     @staticmethod
     def add_connectionerr_mock_response():
         responses.add(
@@ -149,6 +160,24 @@ def test_bad_login():
         assert not result.stdout
         assert result.stderr == "Bad login\n"
 
+    @staticmethod
+    @responses.activate
+    def test_not_json():
+        TestGenerateToken.add_notjson_mock_response()
+        runner = CliRunner(mix_stderr=False)
+        result = runner.invoke(
+            generate_token.main,
+            args=[
+                TestGenerateToken.USER_SWITCH,
+                TestGenerateToken.USER_TEXT,
+                TestGenerateToken.PSWD_SWITCH,
+                TestGenerateToken.PSWD_TEXT,
+            ],
+        )
+        assert result.exit_code == 1
+        assert not result.stdout
+        assert result.stderr == "NOT Jason\n"
+
     @staticmethod
     @responses.activate
     def test_connection_failed():
@@ -169,3 +198,27 @@ def test_connection_failed():
         assert -1 != str(result.stderr).find(
             "Cannot connect to 'http://pbench.example.com/api/v1/login'"
         )
+
+    @staticmethod
+    @responses.activate
+    def test_output_file(tmp_path):
+        output_d = tmp_path / "test_output_file"
+        output_d.mkdir()
+        output_file = output_d / "token.file"
+        TestGenerateToken.add_success_mock_response()
+        runner = CliRunner(mix_stderr=False)
+        result = runner.invoke(
+            generate_token.main,
+            args=[
+                TestGenerateToken.USER_SWITCH,
+                TestGenerateToken.USER_TEXT,
+                TestGenerateToken.PSWD_SWITCH,
+                TestGenerateToken.PSWD_TEXT,
+                TestGenerateToken.OUTPUT_SWITCH,
+                str(output_file),
+            ],
+        )
+        assert result.exit_code == 0
+        assert result.stdout == ""
+        assert not result.stderr_bytes
+        assert Path(output_file).read_text() == f"{TestGenerateToken.TOKEN_TEXT}\n"