docs(logs): address PR feedback on canister logs extensions

Author: mraszyk

docs/references/ic-interface-spec/abstract-behavior.md

@@ -4236,7 +4236,7 @@ S with
 
 #### Canister out of cycles
 
-Once a canister runs out of cycles, its code is uninstalled (cf. [IC Management Canister: Code uninstallation](#rule-uninstall)), the canister changes in the canister history are dropped (their total number is preserved), and the allocations are set to zero:
+Once a canister runs out of cycles, its code is uninstalled (cf. [IC Management Canister: Code uninstallation](#rule-uninstall)), the canister changes in the canister history are dropped (their total number is preserved), and the allocations and the canister log memory limit are set to zero:
 
 Conditions  
 

docs/references/ic-interface-spec/management-canister.md

@@ -960,7 +960,7 @@ A snapshot may be deleted only by the controllers of the canister that the snaps
 
 ### IC method `fetch_canister_logs` {#ic-fetch_canister_logs}
 
-This method can be called by canisters via replicated calls, i.e., it cannot be called by external users via replicated (update) calls.
+This method can be called by canisters via replicated calls, but it cannot be called by external users via replicated (update) calls.
 This method can also be called via non-replicated (query) calls: by external users directly and by canisters from composite query methods and their callbacks.
 A call from a composite query is executed against the state of the subnet hosting the calling canister and can thus only target canisters hosted by that subnet.
 
@@ -982,7 +982,7 @@ A single log is a record with the following fields:
 - `timestamp_nanos` (`nat64`): the timestamp as nanoseconds since 1970-01-01 at which the log was recorded;
 - `content` (`blob`): the actual content of the log;
 
-To filter canister logs, an optional filter can be provided and have one of the following variants:
+To filter canister logs, an optional filter can be provided and has one of the following variants:
 - `by_idx` (`record { start : nat64; end : nat64 }`): only logs are returned whose `idx` is within the provided range (`start` is inclusive, but `end` is exclusive);
 - `by_timestamp_nanos` (`record { start : nat64; end : nat64 }`): only logs are returned whose `timestamp_nanos` is within the provided range (`start` is inclusive, but `end` is exclusive).
 

docs/references/management-canister.md

@@ -27,6 +27,7 @@ Several methods accept or return a `canister_settings` record. The fields are:
 | `wasm_memory_limit` | `nat` | `0` | Upper limit on Wasm heap memory in bytes (0 = no limit) |
 | `wasm_memory_threshold` | `nat` | `0` | Remaining Wasm memory threshold that triggers the low-memory hook |
 | `log_visibility` | `log_visibility` | `controllers` | Who can read canister logs: `controllers`, `public`, or `allowed_viewers(vec principal)` |
+| `log_memory_limit` | `nat` | `4096` | Memory in bytes for storing canister logs: either `0` or between `4096` and `2097152` (2 MiB) |
 | `snapshot_visibility` | `snapshot_visibility` | `controllers` | Who can list and read canister snapshots: `controllers`, `public`, or `allowed_viewers(vec principal)` |
 | `status_visibility` | `status_visibility` | `controllers` | Who can read the canister status: `controllers`, `public`, or `allowed_viewers(vec principal)` |
 | `environment_variables` | `opt record` | `null` | Key-value pairs accessible during canister execution |
@@ -129,7 +130,7 @@ Returns detailed information about a canister: status, settings, module hash, cy
   - `settings`: the definite canister settings currently in effect
   - `module_hash` (`opt blob`): SHA-256 of installed module (`null` if empty)
   - `memory_size` (`nat`): total memory consumed
-  - `memory_metrics`: breakdown by component (Wasm memory, stable memory, globals, binary, custom sections, history, chunk store, snapshots)
+  - `memory_metrics`: breakdown by component (Wasm memory, stable memory, globals, binary, custom sections, history, chunk store, snapshots, log memory store)
   - `cycles` (`nat`): current cycle balance
   - `reserved_cycles` (`nat`): reserved cycle balance
   - `idle_cycles_burned_per_day` (`nat`): daily idle burn rate
@@ -534,13 +535,17 @@ For Bitcoin integration patterns, see the [Bitcoin guide](../guides/chain-fusion
 
 ### `fetch_canister_logs`
 
-Returns the most recent log entries for a canister. Logs are produced by `ic0.debug_print` and trap messages. Logs persist across upgrades but are purged on reinstall or uninstall. Total log size is capped at 4 KiB.
+Returns log entries for a canister. Logs are produced by `ic0.debug_print` and trap messages. Logs persist across upgrades but are purged on reinstall or uninstall. The oldest logs are purged once the memory used for canister logs exceeds the `log_memory_limit` canister setting.
 
-- **Caller:** External users via query calls, or canisters from composite queries (not callable via replicated calls)
-- **Parameters:** `canister_id` (`principal`)
+- **Caller:** Canisters via replicated calls or composite queries, and external users via query calls (external users cannot call it via replicated calls)
+- **Parameters:**
+  - `canister_id` (`principal`)
+  - `filter` (`opt variant { by_idx : record { start : nat64; end : nat64 }; by_timestamp_nanos : record { start : nat64; end : nat64 } }`): returns only the logs whose `idx` or `timestamp_nanos` falls in the given range (`start` is inclusive, `end` is exclusive)
 - **Returns:**
   - `canister_log_records` (`vec record { idx : nat64; timestamp_nanos : nat64; content : blob }`)
 
+The total size of the returned logs is bounded by an implementation-defined constant chosen so as not to exceed the maximum response size. When the selected logs do not all fit, an unfiltered read trims the oldest records, so the response ends with the newest log, and a filtered read trims the newest records, so the response starts with the oldest log matching the filter.
+
 Log visibility is controlled by the `log_visibility` canister setting.
 
 For practical usage, see the [canister logs guide](../guides/canister-management/logs.md).

public/references/ic.did

@@ -515,7 +515,7 @@ type fetch_canister_logs_args = record {
     filter : opt variant {
         by_idx : record { start : nat64; end : nat64 };
         by_timestamp_nanos : record { start : nat64; end : nat64 };
-    }
+    };
 };
 
 type canister_log_record = record {