Merge lp:~hloeung/ubuntu-repository-cache/squid-cache-eviction-watermarks into lp:ubuntu-repository-cache

[Haw Loeung]

Allow overriding squid-cache's watermark thresholds (cache_swap_low & cache_swap_high) to tune memory usage

[Paul Collins (pjdc)]

review: Approve (lgtm)

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 343

=== modified file '.bzrignore'
--- .bzrignore	2021-02-22 00:49:41 +0000
+++ .bzrignore	2022-05-23 03:31:53 +0000
@@ -10,6 +10,7 @@
 .tox/
 .cache/
 __pycache__/
+build/
 builds/
 deps/
 repo-info

=== added file 'charmcraft.yaml'
--- charmcraft.yaml	1970-01-01 00:00:00 +0000
+++ charmcraft.yaml	2022-05-23 03:31:53 +0000
@@ -0,0 +1,17 @@
+type: "charm"
+bases:
+    - build-on:
+      - name: "ubuntu"
+        channel: "20.04"
+      - name: "ubuntu"
+        channel: "22.04"
+      run-on:
+      - name: "ubuntu"
+        channel: "20.04"
+      - name: "ubuntu"
+        channel: "22.04"
+parts:
+  charm:
+    source: .
+    plugin: reactive
+    build-snaps: [charm]

=== modified file 'config.yaml'
--- config.yaml	2021-03-09 04:28:19 +0000
+++ config.yaml	2022-05-23 03:31:53 +0000
@@ -83,6 +83,18 @@
     description: |
       Configurable option (in MBytes) to tune/override storage used by
       squid cache. If 0 or unset, then auto-calculate.
+  cache-swap-high:
+    default: 85
+    type: int
+    description: |
+      Configurable option to tune/override the high-water mark for cache object
+      eviction.
+  cache-swap-low:
+    default: 80
+    type: int
+    description: |
+      Configurable option to tune/override the low-water mark for cache object
+      eviction.
   nagios_context:
     default: 'juju'
     type: string

=== modified file 'lib/ubuntu_repository_cache/squid.py'
--- lib/ubuntu_repository_cache/squid.py	2021-03-10 00:53:26 +0000
+++ lib/ubuntu_repository_cache/squid.py	2022-05-23 03:31:53 +0000
@@ -196,6 +196,8 @@
     context['Cache_Storage_Config'] = cache_dirs()
     context['Cache_Peers'] = peer_config()
     context['Cache_Hostname'] = hookenv.unit_private_ip()
+    context['Cache_Swap_Low'] = config.get('cache-swap-low', 80)
+    context['Cache_Swap_High'] = config.get('cache-swap-high', 85)
     if config['squid_snmp']:
         context[
             'Snmp_Config'

=== modified file 'templates/squid-deb-proxy/squid-deb-proxy.conf'
--- templates/squid-deb-proxy/squid-deb-proxy.conf	2021-06-08 03:24:12 +0000
+++ templates/squid-deb-proxy/squid-deb-proxy.conf	2022-05-23 03:31:53 +0000
@@ -42,8 +42,8 @@
 {{ Cache_Storage_Config }}
 
 # Cache swap more aggressive to avoid having the cache size going above the cache_dir size parameter
-cache_swap_low 80
-cache_swap_high 85
+cache_swap_low {{ Cache_Swap_Low }}
+cache_swap_high {{ Cache_Swap_High }}
 
 # use different logs
 cache_log /var/log/squid-deb-proxy/cache.log