docs: new capability to advertise session IDs
In future patches, we will add the ability for Git servers and clients
to advertise unique session IDs via protocol capabilities. This
allows for easier debugging when both client and server logs are
available.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index ba869a7..9dfade9 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -27,8 +27,8 @@
(push to server) process.
The 'ofs-delta' and 'side-band-64k' capabilities are sent and recognized
-by both upload-pack and receive-pack protocols. The 'agent' capability
-may optionally be sent in both protocols.
+by both upload-pack and receive-pack protocols. The 'agent' and 'session-id'
+capabilities may optionally be sent in both protocols.
All other capabilities are only recognized by the upload-pack (fetch
from server) process.
@@ -365,3 +365,16 @@
fetch-pack may send "filter" commands to request a partial clone
or partial fetch and request that the server omit various objects
from the packfile.
+
+session-id=<session id>
+-----------------------
+
+The server may advertise a session ID that can be used to identify this process
+across multiple requests. The client may advertise its own session ID back to
+the server as well.
+
+Session IDs should be unique to a given process. They must fit within a
+packet-line, and must not contain non-printable or whitespace characters. The
+current implementation uses trace2 session IDs (see
+link:api-trace2.html[api-trace2] for details), but this may change and users of
+the session ID should not rely on this fact.
