Add exceptions

.circleci/config.yml

@@ -16,7 +16,7 @@ jobs:
             mkdir -p ~/.virtualenvs
             python3 -m venv ~/.virtualenvs/singer-python
             source ~/.virtualenvs/singer-python/bin/activate
-            pip install -U pip setuptools
+            pip install -U 'pip<19.2' 'setuptools<51.0.0'
             make install
       - run:
           name: 'Run tests'

singer/__init__.py

@@ -73,6 +73,14 @@
     get_currently_syncing,
 )
 
+from singer.exceptions import (
+    SingerConfigurationError,
+    SingerDiscoveryError,
+    SingerError,
+    SingerRetryableRequestError,
+    SingerSyncError,
+)
+
 if __name__ == "__main__":
     import doctest
     doctest.testmod()

singer/exceptions.py

@@ -0,0 +1,30 @@
+"""
+The exceptions module contains Exception subclasses whose instances might be
+raised by the singer library or taps that use the singer library.
+"""
+
+class SingerError(Exception):
+    """The base Exeception class for singer"""
+    def __init__(self, message):
+        """Create an exeception with a multiline error message
+
+        The first line is the error's class name. The subsequent lines are
+        the message that class was created with.
+        """
+        super().__init__('{}\n{}'.format(self.__class__.__name__, message))
+
+
+class SingerConfigurationError(SingerError):
+    """The base class of errors encountered before discovery and before sync mode"""
+
+
+class SingerDiscoveryError(SingerError):
+    """The base class of errors encountered in discovery mode"""
+
+
+class SingerSyncError(SingerError):
+    """The base class of errors encountered in sync mode"""
+
+
+class SingerRetryableRequestError(SingerError):
+    """This error is meant to be thrown when a tap encounters a retryable request"""

tests/test_exceptions.py

@@ -0,0 +1,68 @@
+import unittest
+
+from singer.exceptions import SingerConfigurationError
+from singer.exceptions import SingerDiscoveryError
+from singer.exceptions import SingerError
+from singer.exceptions import SingerRetryableRequestError
+from singer.exceptions import SingerSyncError
+
+class TestSingerErrors(unittest.TestCase):
+    def test_SingerError_prints_correctly(self):
+        error_text = "An error occured"
+
+        with self.assertRaises(SingerError) as test_run:
+            raise SingerError(error_text)
+
+        expected_text = "SingerError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))
+
+    def test_SingerConfigurationError_prints_correctly(self):
+        error_text = "An error occured"
+
+        with self.assertRaises(SingerConfigurationError) as test_run:
+            raise SingerConfigurationError(error_text)
+
+        expected_text = "SingerConfigurationError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))
+
+    def test_SingerDiscoveryError_prints_correctly(self):
+        error_text = "An error occured"
+
+        with self.assertRaises(SingerDiscoveryError) as test_run:
+            raise SingerDiscoveryError(error_text)
+
+        expected_text = "SingerDiscoveryError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))
+
+    def test_SingerSyncError_prints_correctly(self):
+        error_text = "An error occured"
+
+        with self.assertRaises(SingerSyncError) as test_run:
+            raise SingerSyncError(error_text)
+
+        expected_text = "SingerSyncError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))
+
+    def test_SingerRetryableRequestError_prints_correctly(self):
+        error_text = "An error occured"
+
+        with self.assertRaises(SingerRetryableRequestError) as test_run:
+            raise SingerRetryableRequestError(error_text)
+
+        expected_text = "SingerRetryableRequestError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))
+
+    def test_SingerError_prints_multiple_lines_correctly(self):
+        error_text = "\n".join(["Line 1", "Line 2", "Line 3"])
+
+        with self.assertRaises(SingerError) as test_run:
+            raise SingerError(error_text)
+
+        expected_text = "SingerError\n" + error_text
+        self.assertEquals(expected_text,
+                          str(test_run.exception))