Add support for stage logs option (#25)

Author: ayushr2

README.md

@@ -43,6 +43,8 @@ stages = [{
   "privileged": True,
   # the number of seconds until the container is killed (optional, defaults to 30)
   "timeout": 30,
+  # enable saving the logs from this stage
+  "logs": False,
   # container environment additions/overrides (optional, defaults to none)
   "env": {
     "VAR1": "1"

chainlink/__init__.py

@@ -108,11 +108,12 @@ async def _run_stage(self, stage, mount, environ):
         result = {
             "data": self.client.api.inspect_container(container.id)["State"],
             "killed": killed,
-            "logs": {
-                "stdout": container.logs(stderr=False, timestamps=True),
-                "stderr": container.logs(stdout=False, timestamps=True),
-            },
+            "logs": {"stdout": None, "stderr": None},
         }
+        if stage.get("logs", True):
+            result["logs"]["stdout"] = container.logs(stderr=False, timestamps=True)
+            result["logs"]["stderr"] = container.logs(stdout=False, timestamps=True)
+
         result["success"] = (not killed) and (result["data"]["ExitCode"] == 0)
         container.remove()