Cope with connection errors to cloud backend during output operation

Author: dflook

image/tools/convert_output.py

@@ -40,11 +40,27 @@ def convert_to_github(outputs: Dict) -> Iterable[Union[Mask, Output]]:
 
             yield Output(name, str(value))
 
+def read_input(s: str) -> dict:
+    """
+    If there is a problem connecting to terraform, the output contains junk lines we need to skip over
+    """
+
+    # Remove any lines that don't start with a {
+    # This is because terraform sometimes outputs junk lines
+    # before the JSON output
+    lines = s.splitlines()
+    while lines and not lines[0].startswith('{'):
+        lines.pop(0)
+
+    jstr = '\n'.join(lines)
+    return json.loads(jstr)
+
+
 if __name__ == '__main__':
 
     input_string = sys.stdin.read()
     try:
-        outputs = json.loads(input_string)
+        outputs = read_input(input_string)
         if not isinstance(outputs, dict):
             raise Exception('Unable to parse outputs')
     except:

tests/test_output.py

@@ -1,5 +1,5 @@
 import json
-from convert_output import convert_to_github, Mask, Output
+from convert_output import convert_to_github, Mask, Output, read_input
 
 
 def test_string():
@@ -40,9 +40,11 @@ def test_number():
         }
     }
 
-    expected_output = [Output(name='int', value='123'),
- Mask(value='123'),
- Output(name='sensitive_int', value='123')]
+    expected_output = [
+        Output(name='int', value='123'),
+        Mask(value='123'),
+        Output(name='sensitive_int', value='123')
+    ]
 
     output = list(convert_to_github(input))
     assert output == expected_output
@@ -305,3 +307,44 @@ def test_compound():
 
     output = list(convert_to_github(input))
     assert output == expected_output
+
+
+def test_read_input_with_junk_lines():
+    input_string = ''' There was an error connecting to Terraform Cloud. Please do not exit
+Terraform to prevent data loss! Trying to restore the connection...
+
+Still trying to restore the connection... (3s elapsed)
+Still trying to restore the connection... (5s elapsed)
+{
+    "output1": {"type": "string", "value": "value1", "sensitive": false}
+}'''
+    result = read_input(input_string)
+    assert result == {
+        "output1": {"type": "string", "value": "value1", "sensitive": False}
+    }
+
+def test_read_input_without_junk_lines():
+    input_string = '''{
+    "output1": {"type": "string", "value": "value1", "sensitive": false}
+}'''
+    result = read_input(input_string)
+    assert result == {
+        "output1": {"type": "string", "value": "value1", "sensitive": False}
+    }
+
+def test_read_input_empty_string():
+    input_string = ''
+    try:
+        read_input(input_string)
+        assert False, "Expected an exception"
+    except json.JSONDecodeError:
+        pass
+
+def test_read_input_invalid_json():
+    input_string = '''{
+    "output1": {"type": "string", "value": "value1", "sensitive": false'''
+    try:
+        read_input(input_string)
+        assert False, "Expected an exception"
+    except json.JSONDecodeError:
+        pass