searcher: stop setting cache size env vars, let searcher size its caches

The chart derived SEARCHER_CACHE_SIZE_MB and SYMBOLS_CACHE_SIZE_MB from
searcher.storageSize with trimSuffix "Gi" | mul 450. Any other unit
(150G, 50000Mi) rendered 0, which disables eviction and fills the volume.

searcher already sizes each cache to 45% of its volume when the env vars
are unset, so drop the chart-side arithmetic and the autoCacheSize knob.
Admins who want a fixed size set the env vars under searcher.env.

Amp-Thread-ID: https://ampcode.com/threads/T-01a0ee04-46d0-702b-9932-65e20f260c77
Co-authored-by: Amp <amp@ampcode.com>

Author: marcleblanc2

charts/sourcegraph/CHANGELOG.md

@@ -8,6 +8,7 @@ Use `**BREAKING**:` to denote a breaking change
 
 ## Unreleased
 
+- **BREAKING**: The chart no longer sets `SEARCHER_CACHE_SIZE_MB` and `SYMBOLS_CACHE_SIZE_MB`; `searcher` sizes each cache to 45% of its cache volume at startup. Previously the chart derived them from `searcher.storageSize` assuming a `Gi` suffix, so any other unit (e.g. `150G`) rendered `0`, which disables eviction and fills the volume. `searcher.autoCacheSize` is removed. To pin an explicit size, set the env vars under `searcher.env`
 - Added opt-in Redis config management through `redisCache.config.enabled` and `redisStore.config.enabled` (both default to `false`). Default deployments retain their image configs, custom mounts, authentication, and memory settings. When enabled, the chart mounts `/etc/redis/redis.conf` and supports `existingConfig`, `maxmemory`, `maxmemoryRatio`, `maxmemoryPolicy`, and `additionalConfig`. See [Enabling Redis config management](README.md#enabling-redis-config-management) before opting in, especially when using custom images or Secret-mounted configs.
 - With Redis config management enabled, the chart sizes `maxmemory` at 75% of `resources.limits.memory` to leave room for overhead; this reduces, but does not eliminate, OOM risk. Ratios must be greater than 0 and less than 1. Auto-sizing is skipped in local development mode or when the limit is absent or unrecognised. At the default 7Gi limit, opting in lowers the effective cap from 6GiB to 5.25GiB: `redis-cache` evicts earlier, but `redis-store` uses `noeviction`, so its write-error ceiling drops too. Set `redisStore.config.maxmemory: 6gb` to keep the old ceiling if the pod has sufficient memory.
 - Added a `network-policy` example, which limits Executor and Executor job pods to the frontend API

charts/sourcegraph/README.md

@@ -403,7 +403,6 @@ In addition to the documented values, all services also support the following va
 | redisStore.storageAnnotations | object | `{}` | Optional annotations to add to the `redis-store` PVC |
 | redisStore.storageSize | string | `"100Gi"` | PVC Storage Request for `redis-store` data volume |
 | redisStore.storageSubPath | string | `""` | Optional subPath for the `redis-store` primary data volume mount |
-| searcher.autoCacheSize | bool | `false` | When enabled, omit the `SEARCHER_CACHE_SIZE_MB` and `SYMBOLS_CACHE_SIZE_MB` env vars so `searcher` auto-sizes its cache to ~45% of the live cache volume. This tracks PVC expansion automatically, whereas the hardcoded env vars are frozen to the initial `storageSize` and do not follow later disk growth. |
 | searcher.containerSecurityContext | object | `{"allowPrivilegeEscalation":false,"readOnlyRootFilesystem":true,"runAsGroup":101,"runAsUser":100}` | Security context for the `searcher` container, learn more from the [Kubernetes documentation](https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#set-the-security-context-for-a-container) |
 | searcher.env | object | the chart will add some default environment values | Environment variables for the `searcher` container |
 | searcher.image.defaultTag | string | `"6.0.0@sha256:c7508abda2202d4a33400ce23a95dd8d59fe6220d85d7fbee6fb186c55931336"` | Docker image tag for the `searcher` image |

charts/sourcegraph/templates/searcher/searcher.StatefulSet.yaml

@@ -57,30 +57,6 @@ spec:
         - name: {{ $name }}
           {{- $item | toYaml | nindent 10 }}
         {{- end }}
-        {{- if not .Values.searcher.autoCacheSize }}
-        # When autoCacheSize is enabled, these env vars are omitted so searcher
-        # sizes its cache to ~45% of the live cache volume, tracking PVC
-        # expansion automatically. SEARCHER_CACHE_SIZE_MB / SYMBOLS_CACHE_SIZE_MB
-        # are deprecated in favor of this auto-detection.
-        - name: SEARCHER_CACHE_SIZE_MB
-          # Set the cache size to ~45% of the PVC size
-          {{- if .Values.searcher.storageSize }}
-          value: {{ trimSuffix "Gi" .Values.searcher.storageSize | mul 450 | quote }}
-          {{- else }}
-          # This value is ~45% of the default value for
-          # storageSize in the VolumeClaimTemplate below
-          value: "11700"
-          {{- end }}
-        - name: SYMBOLS_CACHE_SIZE_MB
-          # Set the cache size to ~45% of the PVC size
-          {{- if .Values.searcher.storageSize }}
-          value: {{ trimSuffix "Gi" .Values.searcher.storageSize | mul 450 | quote }}
-          {{- else }}
-          # This value is ~45% of the default value for
-          # storageSize in the VolumeClaimTemplate below
-          value: "11700"
-          {{- end }}
-        {{- end }}
         - name: POD_NAME
           valueFrom:
             fieldRef:

charts/sourcegraph/tests/searcherCacheSize_test.yaml

@@ -0,0 +1,36 @@
+suite: searcher cache size
+templates:
+  - searcher/searcher.StatefulSet.yaml
+tests:
+- it: should not set cache size env vars, searcher sizes its caches from the volume
+  set:
+    searcher.storageSize: 150G
+  asserts:
+  - notContains:
+      path: spec.template.spec.containers[0].env
+      content:
+        name: SEARCHER_CACHE_SIZE_MB
+      any: true
+  - notContains:
+      path: spec.template.spec.containers[0].env
+      content:
+        name: SYMBOLS_CACHE_SIZE_MB
+      any: true
+- it: should pass through cache size env vars set under searcher.env
+  set:
+    searcher.env:
+      SEARCHER_CACHE_SIZE_MB:
+        value: "20000"
+      SYMBOLS_CACHE_SIZE_MB:
+        value: "1500"
+  asserts:
+  - contains:
+      path: spec.template.spec.containers[0].env
+      content:
+        name: SEARCHER_CACHE_SIZE_MB
+        value: "20000"
+  - contains:
+      path: spec.template.spec.containers[0].env
+      content:
+        name: SYMBOLS_CACHE_SIZE_MB
+        value: "1500"

charts/sourcegraph/values.yaml

@@ -1261,11 +1261,6 @@ searcher:
     create: false
     # -- Name of the ServiceAccount to be created or an existing ServiceAccount
     name: ""
-  # -- When enabled, omit the `SEARCHER_CACHE_SIZE_MB` and `SYMBOLS_CACHE_SIZE_MB`
-  # env vars so `searcher` auto-sizes its cache to ~45% of the live cache volume.
-  # This tracks PVC expansion automatically, whereas the hardcoded env vars are
-  # frozen to the initial `storageSize` and do not follow later disk growth.
-  autoCacheSize: false
   # -- Size of the PVC for searcher pods to store cache data
   storageSize: 26Gi
   # -- Optional subPath for the `searcher` primary data volume mount