Merge "Do not send compression as acceptable encoding"

releasenotes/notes/do-not-offer-compression-encoding-884ca8a7458cb096.yaml

@@ -0,0 +1,16 @@
+---
+fixes:
+  - |
+    Fixes unreliable behavior with ETag interactions with some BMCs as
+    opportunistic use of compressed responses may cause the BMC to change
+    an ETag response to "Weak", which is to be expected as an ETag represents
+    an absolute byte-by-byte response consistency, and compression cannot
+    reliably honor that contract. Introduction of a client perceiving a
+    "Weak" ETag may not be expected by the server, and the server may reject
+    responses because the ETag is not a "Strong" ETag when we respond or
+    interact with a resource.
+
+    As a result, requests no longer offer oppurtunistic compression
+    of responses as an acceptable possibility, which overall has minimal
+    impact, espescially when compared to the value of consistent BMC
+    behavior and interaction.

sushy/connector.py

@@ -50,6 +50,15 @@ class Connector(object):
         # By default, we ask HTTP server to shut down HTTP connection we've
         # just used.
         self._session.headers['Connection'] = 'close'
+        # NOTE(TheJulia): Depending on the BMC, offering compression as an
+        # acceptable response changes the ETag behavior to offering an
+        # automatic "weak" ETag response, which is appropriate because the
+        # body content *may* not be a byte for byte match given compression.
+        # Overall, the value of compression is less than the value of concise
+        # interaction with the BMC. Setting to identity basically means
+        # "without modification or compression". By default, python-requests
+        # indicates responses can be compressed.
+        self._session.headers['Accept-Encoding'] = 'identity'
 
         if username or password:
             LOG.warning('Passing username and password to Connector is '