added ability to provide schema in config (#14)

Co-authored-by: Josh Lloyd <jlloyd@ip-10-0-0-10.ec2.internal>

README.md

@@ -89,7 +89,7 @@ provided at the top-level will be the default values for each stream.:
 Parameters that appear at the stream-level
 will overwrite their top-level counterparts except where noted below:
 - `name`: required: name of the stream.
-- `path`: optional: the path appeneded to the `api_url`.
+- `path`: optional: the path appended to the `api_url`.
 - `params`: optional: an object of objects that provide the `params` in a `requests.get` method.
   Stream level params will be merged with top-level params with stream level params overwriting 
   top-level params with the same key.
@@ -104,6 +104,9 @@ will overwrite their top-level counterparts except where noted below:
   turned into a json string and processed in that format. This is also automatically done for any lists within the records; therefore,
   records are not duplicated for each item in lists.
 - `num_inference_keys`: optional: number of records used to infer the stream's schema. Defaults to 50.
+- `scheam`: optional: A valid Singer schema or a path-like string that provides
+  the path to a `.json` file that contains a valid Singer schema. If provided, 
+  the schema will not be inferred from the results of an api call.
 
 ## Pagination
 Pagination is a complex topic as there is no real single standard, and many different implementations.  Unless options are provided, both the request and results stype default to the `default`, which is the pagination style originally implemented.

tap_rest_api_msdk/tap.py

@@ -1,6 +1,7 @@
 """rest-api tap class."""
 
 import copy
+import json
 from typing import Any, List
 
 import requests
@@ -143,6 +144,19 @@ class TapRestApiMsdk(Tap):
             "name", th.StringType, required=True, description="name of the stream"
         ),
     )
+    stream_properties.append(
+        th.Property(
+            "schema",
+            th.CustomType(
+                {"anyOf": [{"type": "string"}, {"type": "null"}, {"type:": "object"}]}
+            ),
+            required=False,
+            description="A valid Singer schema or a path-like string that provides "
+            "the path to a `.json` file that contains a valid Singer "
+            "schema. If provided, the schema will not be inferred from "
+            "the results of an api call.",
+        ),
+    )
 
     # add streams schema to top-level properties
     top_level_properties.append(
@@ -177,6 +191,33 @@ def discover_streams(self) -> List[DynamicStream]:  # type: ignore
             params = {**self.config.get("params", {}), **stream.get("params", {})}
             headers = {**self.config.get("headers", {}), **stream.get("headers", {})}
 
+            schema = {}
+            schema_config = stream.get("schema")
+            if isinstance(schema_config, str):
+                self.logger.info("Found path to a schema, not doing discovery.")
+                with open(schema_config, "r") as f:
+                    schema = json.load(f)
+
+            elif isinstance(schema_config, dict):
+                self.logger.info("Found schema in config, not doing discovery.")
+                builder = SchemaBuilder()
+                builder.add_schema(schema_config)
+                schema = builder.to_schema()
+
+            else:
+                self.logger.info("No schema found. Inferring schema from API call.")
+                schema = self.get_schema(
+                    records_path,
+                    except_keys,
+                    stream.get(
+                        "num_inference_records",
+                        self.config["num_inference_records"],
+                    ),
+                    path,
+                    params,
+                    headers,
+                )
+
             streams.append(
                 DynamicStream(
                     tap=self,
@@ -196,17 +237,7 @@ def discover_streams(self) -> List[DynamicStream]:  # type: ignore
                     pagination_request_style=self.config["pagination_request_style"],
                     pagination_response_style=self.config["pagination_response_style"],
                     pagination_page_size=self.config.get("pagination_page_size"),
-                    schema=self.get_schema(
-                        records_path,
-                        except_keys,
-                        stream.get(
-                            "num_inference_records",
-                            self.config["num_inference_records"],
-                        ),
-                        path,
-                        params,
-                        headers,
-                    ),
+                    schema=schema,
                 )
             )
 

tests/schema.json

@@ -0,0 +1,26 @@
+{
+  "$schema": "http://json-schema.org/schema#",
+  "type": "object",
+  "properties": {
+    "key1": {
+      "type": "string"
+    },
+    "key2": {
+      "type": "string"
+    },
+    "key3": {
+      "type": "string"
+    },
+    "field1": {
+      "type": "string"
+    },
+    "field2": {
+      "type": "integer"
+    }
+  },
+  "required": [
+    "key1",
+    "key2",
+    "key3"
+  ]
+}

tests/test_tap.py

@@ -1,7 +1,12 @@
+import json
+
 from tap_rest_api_msdk.tap import TapRestApiMsdk
 
 from tests.test_streams import config, setup_api
 
+with open("tests/schema.json", "r") as f:
+    BASIC_SCHEMA = json.load(f)
+
 
 def test_schema_inference(requests_mock):
     setup_api(requests_mock)
@@ -10,18 +15,25 @@ def test_schema_inference(requests_mock):
         0
     ]
 
-    assert stream0.schema == {
-        "$schema": "http://json-schema.org/schema#",
-        "required": ["key1", "key2", "key3"],
-        "type": "object",
-        "properties": {
-            "field1": {"type": "string"},
-            "field2": {"type": "integer"},
-            "key1": {"type": "string"},
-            "key2": {"type": "string"},
-            "key3": {"type": "string"},
-        },
-    }
+    assert stream0.schema == BASIC_SCHEMA
+
+
+def test_schema_from_file():
+    configs = config()
+    configs["streams"][0]["schema"] = "tests/schema.json"
+
+    s0 = TapRestApiMsdk(config=configs, parse_env_config=True).discover_streams()[0]
+
+    assert s0.schema == BASIC_SCHEMA
+
+
+def test_schema_from_object():
+    configs = config()
+    configs["streams"][0]["schema"] = BASIC_SCHEMA
+
+    s0 = TapRestApiMsdk(config=configs, parse_env_config=True).discover_streams()[0]
+
+    assert s0.schema == BASIC_SCHEMA
 
 
 def test_multiple_streams(requests_mock):