maint: prep for v3.1.2 release (#1800)

## Which problem is this PR solving?

Prepare for v3.1.2 release

## Short description of the changes

- update changelog, release notes, and update metric doc

Author: VinozzZ

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Refinery Changelog
 
+## 3.1.2 2026-03-25
+
+This release addresses security vulnerabilities CVE-2026-27139, CVE-2026-27142, and CVE-2026-25679.
+
+### Features
+
+- feat: add capacity/limit companion metrics for queues and memory by @mterhar in https://github.com/honeycombio/refinery/pull/1799
+
+### Maintenance
+
+- maint(deps): bump the minor-patch group across 1 directory with 21 updates by @dependabot in https://github.com/honeycombio/refinery/pull/1795
+
 ## 3.1.1 2026-02-25
 
 ### Features

RELEASE_NOTES.md

@@ -2,6 +2,14 @@
 
 While [CHANGELOG.md](./CHANGELOG.md) contains detailed documentation and links to all the source code changes in a given release, this document is intended to be aimed at a more comprehensible version of the contents of the release from the point of view of users of Refinery.
 
+## Version 3.1.2
+
+This patch release primarily addresses security vulnerabilities in dependencies.
+
+### Maintenance
+
+- Updated dependencies to address security vulnerabilities CVE-2026-27139, CVE-2026-27142, and CVE-2026-25679.
+
 ## Version 3.1.1
 
 This patch release includes bug fixes and a new feature for configuring additional HTTP headers.

metrics.md

@@ -34,11 +34,14 @@ This table includes metrics with fully defined names.
 | trace_span_count | Histogram | Dimensionless | number of spans in a trace |
 | collector_incoming_queue | Histogram | Dimensionless | number of spans currently in the incoming queue |
 | collector_peer_queue_length | Gauge | Dimensionless | number of spans in the peer queue |
+| collector_peer_queue_capacity | Gauge | Dimensionless | configured maximum number of spans in the peer queue |
 | collector_incoming_queue_length | Gauge | Dimensionless | number of spans in the incoming queue |
+| collector_incoming_queue_capacity | Gauge | Dimensionless | configured maximum number of spans in the incoming queue |
 | collector_peer_queue | Histogram | Dimensionless | number of spans currently in the peer queue |
 | collector_cache_size | Gauge | Dimensionless | number of traces currently stored in the trace cache |
 | collect_cache_entries | Histogram | Dimensionless | Total number of traces currently stored in the cache from all workers |
 | memory_heap_allocation | Gauge | Bytes | current heap allocation |
+| memory_limit | Gauge | Bytes | configured maximum memory allocation for the collector (derived from MaxAlloc or AvailableMemory * MaxMemoryPercentage) |
 | span_received | Counter | Dimensionless | number of spans received by the collector |
 | span_processed | Counter | Dimensionless | number of spans processed by the collector |
 | spans_waiting | UpDown | Dimensionless | number of spans waiting to be processed by the collector |

tools/convert/metricsMeta.yaml

@@ -87,10 +87,18 @@ complete:
       type: Gauge
       unit: Dimensionless
       description: number of spans in the peer queue
+    - name: collector_peer_queue_capacity
+      type: Gauge
+      unit: Dimensionless
+      description: configured maximum number of spans in the peer queue
     - name: collector_incoming_queue_length
       type: Gauge
       unit: Dimensionless
       description: number of spans in the incoming queue
+    - name: collector_incoming_queue_capacity
+      type: Gauge
+      unit: Dimensionless
+      description: configured maximum number of spans in the incoming queue
     - name: collector_peer_queue
       type: Histogram
       unit: Dimensionless
@@ -107,6 +115,10 @@ complete:
       type: Gauge
       unit: Bytes
       description: current heap allocation
+    - name: memory_limit
+      type: Gauge
+      unit: Bytes
+      description: configured maximum memory allocation for the collector (derived from MaxAlloc or AvailableMemory * MaxMemoryPercentage)
     - name: span_received
       type: Counter
       unit: Dimensionless