refactor: update get_osm_extracts func for clarity

src/backend/app/projects/project_crud.py

@@ -576,6 +576,12 @@ def remove_z_dimension(coord):
 
 
 def get_osm_extracts(boundary: str):
+    """Request an extract from raw-data-api and extract the file contents.
+
+    - The query is posted to raw-data-api and job initiated for fetching the extract.
+    - The status of the job is polled every few seconds, until 'SUCCESS' is returned.
+    - The resulting zip file is downloaded, extracted, and data returned.
+    """
     # Filters for osm extracts
     query = {
         "filters": {
@@ -587,43 +593,54 @@ def get_osm_extracts(boundary: str):
         }
     }
 
+    # Boundary to extract data for
     json_boundary = json.loads(boundary)
-
     if json_boundary.get("features", None) is not None:
         query["geometry"] = json_boundary
         # query["geometry"] = json_boundary["features"][0]["geometry"]
-
     else:
         query["geometry"] = json_boundary
 
+    # Filename to generate
+    query["fileName"] = "extract"
+    # File format to generate
+    query["outputType"] = "geojson"
+    extract_filename = f'{query["fileName"]}.{query["outputType"]}'
+    log.debug(f"Setting data extract file name to: {extract_filename}")
+
+    log.debug(f"Query for raw data api: {query}")
     base_url = settings.UNDERPASS_API_URL
     query_url = f"{base_url}/snapshot/"
     headers = {"accept": "application/json", "Content-Type": "application/json"}
 
+    # Send the request to raw data api
     result = requests.post(query_url, data=json.dumps(query), headers=headers)
 
     if result.status_code == 200:
         task_id = result.json()["task_id"]
     else:
         return False
 
+    # Check status of task (PENDING, or SUCCESS)
     task_url = f"{base_url}/tasks/status/{task_id}"
-    # extracts = requests.get(task_url)
     while True:
         result = requests.get(task_url, headers=headers)
         if result.json()["status"] == "PENDING":
-            time.sleep(1)
+            # Wait 2 seconds before polling again
+            time.sleep(2)
         elif result.json()["status"] == "SUCCESS":
             break
 
+    # TODO update code to generate fgb file format
+    # then input the download_url directly into our database
+    # (no need to download the file and extract)
     zip_url = result.json()["result"]["download_url"]
-    zip_url
     result = requests.get(zip_url, headers=headers)
     # result.content
     fp = BytesIO(result.content)
     zfp = zipfile.ZipFile(fp, "r")
-    zfp.extract("Export.geojson", "/tmp/")
-    data = json.loads(zfp.read("Export.geojson"))
+    zfp.extract(extract_filename, "/tmp/")
+    data = json.loads(zfp.read(extract_filename))
 
     for feature in data["features"]:
         properties = feature["properties"]