Deprecate snapshots.read_only_directory configuration option (#7800)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: eddyashton <6000239+eddyashton@users.noreply.github.com>
Co-authored-by: Amaury Chamayou <amchamay@microsoft.com>

Author: 3 people

CHANGELOG.md

@@ -18,6 +18,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - The `ConsensusCommittedEndpointFunction` callback signature now receives a `CommittedTxInfo&` struct (containing `rpc_ctx`, `tx_id`, `status`, `write_set_digest`, `commit_evidence`, `claims_digest`) instead of individual arguments. This enables commit callbacks to construct receipts inline (#7785).
 - `ccf::endpoints::default_respond_on_commit_func` has been removed from the public API. A sample implementation is provided in the logging and basic sample apps (#7785).
 
+### Deprecated
+
+- `snapshots.read_only_directory` configuration option is deprecated and will be removed in a future release. A warning will be logged if this option is set at startup. Use `snapshots.backup_fetch` to have backup nodes automatically fetch snapshots from the primary node instead.
+
 ## [7.0.0-rc0]
 
 [7.0.0-rc0]: https://github.com/microsoft/CCF/releases/tag/ccf-7.0.0-rc0

doc/host_config_schema/cchost_config.json

@@ -507,7 +507,7 @@
         },
         "read_only_directory": {
           "type": ["string", "null"],
-          "description": "Path to read-only snapshots directory"
+          "description": "Path to read-only snapshots directory. Deprecated: this option is deprecated and will be removed in a future release. Use join.fetch_recent_snapshot and snapshots.backup_fetch to have joining and/or backup nodes automatically fetch snapshots from the primary node instead."
         },
         "backup_fetch": {
           "type": "object",

src/host/run.cpp

@@ -615,6 +615,12 @@ namespace ccf
       config.ledger.read_only_directories);
     ledger.register_message_handlers(buffer_processor.get_dispatcher());
 
+    if (config.snapshots.read_only_directory.has_value())
+    {
+      LOG_INFO_FMT(
+        "snapshots.read_only_directory is deprecated and will be removed in a "
+        "future release");
+    }
     snapshots::SnapshotManager snapshots(
       config.snapshots.directory,
       writer_factory,