Implement logging strategy (#444)

* Logging strategy and convert all prints() to logging invocations

trustgraph-flow/trustgraph/chunking/token/chunker.py

@@ -4,12 +4,16 @@ Simple decoder, accepts text documents on input, outputs chunks from the
 as text as separate output objects.
 """
 
+import logging
 from langchain_text_splitters import TokenTextSplitter
 from prometheus_client import Histogram
 
 from ... schema import TextDocument, Chunk
 from ... base import FlowProcessor
 
+# Module logger
+logger = logging.getLogger(__name__)
+
 default_ident = "chunker"
 
 class Processor(FlowProcessor):
@@ -53,12 +57,12 @@ class Processor(FlowProcessor):
             )
         )
 
-        print("Chunker initialised", flush=True)
+        logger.info("Token chunker initialized")
 
     async def on_message(self, msg, consumer, flow):
 
         v = msg.value()
-        print(f"Chunking {v.metadata.id}...", flush=True)
+        logger.info(f"Chunking document {v.metadata.id}...")
 
         texts = self.text_splitter.create_documents(
             [v.text.decode("utf-8")]
@@ -66,7 +70,7 @@ class Processor(FlowProcessor):
 
         for ix, chunk in enumerate(texts):
 
-            print("Chunk", len(chunk.page_content), flush=True)
+            logger.debug(f"Created chunk of size {len(chunk.page_content)}")
 
             r = Chunk(
                 metadata=v.metadata,
@@ -79,7 +83,7 @@ class Processor(FlowProcessor):
 
             await flow("output").send(r)
 
-        print("Done.", flush=True)
+        logger.debug("Document chunking complete")
 
     @staticmethod
     def add_args(parser):