Support pickle model import on API server (#34)

* rename knn_classifier to classifier

* remove deprecated file

* support changing classifier type

* add classifier type flag

* update readme

* linting

* Add method to import persisted model and allow user to set env variable

* pickle is not needed anymore in the server file

* add workaround for using pickle with gunicorn

* linting

---------

Co-authored-by: Tarun <[email protected]>

api_server.py

@@ -1,7 +1,6 @@
 import os
 import json
 import falcon
-
 from multi_classifier import MultiClassifier
 from build_db import (
     open_block_db,
@@ -17,12 +16,21 @@
     count_false_positives,
     count_false_negatives,
 )
+import __main__
+from classifier import (
+    Classifier,
+    import_classifier,
+)
+
+__main__.Classifier = Classifier
+
 
 DATA_DIR = "./data/mainnet/training"
 BLOCK_DB = os.environ.get("BLOCK_DB") or "./block_db.sqlite"
 BN_URL = "http://localhost:5052"
 SELF_URL = "http://localhost:8000"
 DISABLE_CLASSIFIER = "DISABLE_CLASSIFIER" in os.environ
+MODEL_PATH = os.environ.get("MODEL_PATH") or ""
 
 
 class Classify:
@@ -202,9 +210,22 @@ def on_get(self, req, resp, client, start_slot, end_slot=None):
 
 classifier = None
 if not DISABLE_CLASSIFIER:
-    print("Initialising classifier, this could take a moment...")
-    classifier = MultiClassifier(DATA_DIR) if not DISABLE_CLASSIFIER else None
-    print("Done")
+    if MODEL_PATH != "":
+        if MODEL_PATH.endswith(".pkl"):
+            classifier = import_classifier(MODEL_PATH)
+
+        else:
+            print("model path must end with .pkl")
+            exit(0)
+
+    else:
+        print("Initialising classifier, this could take a moment...")
+        classifier = MultiClassifier(DATA_DIR) if not DISABLE_CLASSIFIER else None
+        print("Done")
+
+if classifier is None:
+    print("The classifier was not loaded")
+    exit(0)
 
 block_db = open_block_db(BLOCK_DB)
 

classifier.py

@@ -290,6 +290,18 @@ def persist_classifier(classifier: Classifier, name: str) -> None:
         print(f"Failed to persist classifier due to {e}")
 
 
+def import_classifier(model_path: str) -> Classifier:
+    print(f"""Loading classifier from {model_path}""")
+
+    try:
+        classifier = pickle.load(open(model_path, "rb"))
+        print("Loaded classifier into memory")
+        return classifier
+
+    except Exception as e:
+        print(f"Failed to import classifier due to {e}")
+
+
 def main():
     args = parse_args()
     data_dir = args.data_dir