[release/6.x] Respond with available snapshot rather than Bad Request error (#7415)

Author: eddyashton

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Stop passing nullptr to curl_multi_socket_action (#7371)
 
+### Changed
+
+- When `GET /node/snapshot/{snapshot_name}` requests a `Range` that extends beyond the snapshot's end, the node will now respond with the available sub-range rather than a Bad Request error.
+
 ## [6.0.15]
 
 [6.0.15]: https://github.com/microsoft/CCF/releases/tag/6.0.15

src/node/rpc/node_frontend.h

@@ -2092,14 +2092,12 @@ namespace ccf
 
                 if (range_end > total_size)
                 {
-                  ctx.rpc_ctx->set_error(
-                    HTTP_STATUS_BAD_REQUEST,
-                    ccf::errors::InvalidHeaderValue,
-                    fmt::format(
-                      "End of range {} is larger than total file size {}",
-                      range_end,
-                      total_size));
-                  return;
+                  LOG_DEBUG_FMT(
+                    "Requested snapshot range ending at {}, but file size is "
+                    "only {} - shrinking range end",
+                    range_end,
+                    total_size);
+                  range_end = total_size;
                 }
 
                 if (range_end < range_start)

tests/e2e_operations.py

@@ -352,7 +352,6 @@ def test_snapshot_access(network, args):
             ("foo-foo", "Unable to parse start of range value foo"),
             (f"foo-{b}", "Unable to parse start of range value foo"),
             (f"{b}-{a}", "out of order"),
-            (f"0-{total_size + 1}", "larger than total file size"),
             ("-1-5", "Invalid format"),
             ("-", "Invalid range"),
             ("-foo", "Unable to parse end of range offset value foo"),