From 9dc58a233dfe3c8664b77c681865aae40817f1f7 Mon Sep 17 00:00:00 2001
From: Lucas Pedroza <lucas.pedroza@fauna.com>
Date: Thu, 10 Oct 2024 14:20:45 +0200
Subject: [PATCH] feat: add debug logging

---
 README.md                  | 17 ++++++++++++++
 fauna/client/client.py     |  6 ++++-
 fauna/http/httpx_client.py | 46 +++++++++++++++++++++++++++++++++-----
 3 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 9f848615..44f19f50 100644
--- a/README.md
+++ b/README.md
@@ -568,6 +568,23 @@ options = ChangeFeedOptions(
 client.change_feed(fql('Product.all().toStream()'), options)
 ```
 
+## Logging
+
+Debug logging is handled by the standard logging package in under the `fauna` namespace. We will log the request with body, excluding the Authorization header, as well as the full response.
+
+In your application, you can enable debug logging with the following. Given this is a standard convention in Python, you may want more fine-grained control over which libraries log. See Python's how-to at https://docs.python.org/3/howto/logging.html.
+```python
+import logging
+from fauna.client import Client
+from fauna import fql
+
+logging.basicConfig(
+    level=logging.DEBUG
+)
+c = Client()
+c.query(fql("42"))
+```
+
 ## Setup
 
 ```bash
diff --git a/fauna/client/client.py b/fauna/client/client.py
index d1cac5c8..d1834e0b 100644
--- a/fauna/client/client.py
+++ b/fauna/client/client.py
@@ -1,3 +1,4 @@
+import logging
 from dataclasses import dataclass
 from datetime import timedelta
 from typing import Any, Dict, Iterator, Mapping, Optional, Union, List
@@ -14,6 +15,8 @@
 from fauna.query import Query, Page, fql
 from fauna.query.models import StreamToken
 
+logger = logging.getLogger("fauna")
+
 DefaultHttpConnectTimeout = timedelta(seconds=5)
 DefaultHttpReadTimeout: Optional[timedelta] = None
 DefaultHttpWriteTimeout = timedelta(seconds=5)
@@ -217,7 +220,8 @@ def __init__(
                     max_keepalive_connections=DefaultMaxIdleConnections,
                     keepalive_expiry=idle_timeout_s,
                 ),
-            ))
+            ),
+            logger)
         fauna.global_http_client = c
 
       self._session = fauna.global_http_client
diff --git a/fauna/http/httpx_client.py b/fauna/http/httpx_client.py
index c317d7fa..2ca06593 100644
--- a/fauna/http/httpx_client.py
+++ b/fauna/http/httpx_client.py
@@ -1,4 +1,5 @@
 import json
+import logging
 from contextlib import contextmanager
 from json import JSONDecodeError
 from typing import Mapping, Any, Optional, Iterator
@@ -50,9 +51,10 @@ def close(self) -> None:
 
 class HTTPXClient(HTTPClient):
 
-  def __init__(self, client: httpx.Client):
+  def __init__(self, client: httpx.Client, logger: logging.Logger):
     super(HTTPXClient, self).__init__()
     self._c = client
+    self._logger = logger
 
   def request(
       self,
@@ -69,14 +71,25 @@ def request(
           json=data,
           headers=headers,
       )
+
+      if self._logger.isEnabledFor(logging.DEBUG):
+        headers_to_log = request.headers.copy()
+        headers_to_log.pop("Authorization")
+        self._logger.debug(f"query.request method={request.method} url={request.url} headers={headers_to_log} data={data}")
+
     except httpx.InvalidURL as e:
       raise ClientError("Invalid URL Format") from e
 
     try:
-      return HTTPXResponse(self._c.send(
+      response = self._c.send(
           request,
           stream=False,
-      ))
+      )
+
+      if self._logger.isEnabledFor(logging.DEBUG):
+        self._logger.debug(f"query.response status_code={response.status_code} headers={response.headers} data={response.text}")
+
+      return HTTPXResponse(response)
     except (httpx.HTTPError, httpx.InvalidURL) as e:
       raise NetworkError("Exception re-raised from HTTP request") from e
 
@@ -87,14 +100,35 @@ def stream(
       headers: Mapping[str, str],
       data: Mapping[str, Any],
   ) -> Iterator[Any]:
-    with self._c.stream(
-        "POST", url=url, headers=headers, json=data) as response:
+    request = self._c.build_request(
+      method="POST",
+      url=url,
+      headers=headers,
+      json=data,
+    )
+
+    if self._logger.isEnabledFor(logging.DEBUG):
+      headers_to_log = request.headers.copy()
+      headers_to_log.pop("Authorization")
+      self._logger.debug(f"stream.request method={request.method} url={request.url} headers={headers_to_log} data={data}")
+
+    response = self._c.send(
+      request=request,
+      stream=True,
+    )
+
+    try:
       yield self._transform(response)
+    finally:
+      response.close()
 
   def _transform(self, response):
     try:
       for line in response.iter_lines():
-        yield json.loads(line)
+        loaded = json.loads(line)
+        if self._logger.isEnabledFor(logging.DEBUG):
+          self._logger.debug(f"stream.data data={loaded}")
+        yield loaded
     except httpx.ReadTimeout as e:
       raise NetworkError("Stream timeout") from e
     except (httpx.HTTPError, httpx.InvalidURL) as e: