Merge ~hloeung/charm-k8s-content-cache:cache-all into charm-k8s-content-cache:master

[Haw Loeung]

[Haw Loeung (hloeung)]

As suggested by Thomas, we could make this more flexible supporting a supplied pattern and using Location to add no caching headers for requests matching said pattern.

[Haw Loeung (hloeung)]

Err, that should be to remove the no caching headers forcing cache rather than 'add no caching headers'

Unmerged commits

c4cbb11... by Haw Loeung on 2020-12-17

Add option to always cache ignoring upstream/origin Cache-Control and Expires headers

diff --git a/config.yaml b/config.yaml
index d7dcb7c..ec8793c 100644
--- a/config.yaml
+++ b/config.yaml
@@ -29,6 +29,14 @@ options:
       The backend to use for site, e.g. "http://mybackend.local:80"
 
       This setting is required.
+  cache_all:
+    type: boolean
+    description: >-
+
+      By default, we respect upstream cache headers so Cache-Control
+      and Expires. This overrides that and enables caching even if
+      upstream tells us not to.
+    default: False
   cache_inactive_time:
     type: string
     description: >-
diff --git a/docker/templates/nginx_cfg.tmpl b/docker/templates/nginx_cfg.tmpl
index 4e1ceb3..2523a37 100644
--- a/docker/templates/nginx_cfg.tmpl
+++ b/docker/templates/nginx_cfg.tmpl
@@ -25,6 +25,7 @@ server {
         proxy_cache ${NGINX_KEYS_ZONE};
         proxy_cache_use_stale ${NGINX_CACHE_USE_STALE};
         proxy_cache_valid ${NGINX_CACHE_VALID};
+        ${NGINX_CACHE_ALL}
     }
 
     access_log /dev/stdout content_cache;
diff --git a/src/charm.py b/src/charm.py
index 171e521..9045994 100755
--- a/src/charm.py
+++ b/src/charm.py
@@ -183,12 +183,17 @@ class ContentCacheCharm(CharmBase):
         """Return dict to be used as pod spec's envConfig."""
         config = self.model.config
 
+        cache_all_configs = ''
+        if config.get('cache_all', False):
+            cache_all_configs = "proxy_ignore_headers Cache-Control Expires;"
+
         client_max_body_size = '1m'
         if config.get('client_max_body_size'):
             client_max_body_size = config.get('client_max_body_size')
 
         pod_config = {
             'NGINX_BACKEND': config['backend'],
+            'NGINX_CACHE_ALL': cache_all_configs,
             'NGINX_CACHE_INACTIVE_TIME': config.get('cache_inactive_time', '10m'),
             'NGINX_CACHE_MAX_SIZE': config.get('cache_max_size', '10G'),
             'NGINX_CACHE_PATH': CACHE_PATH,
diff --git a/tests/test_charm.py b/tests/test_charm.py
index 02466ed..153b6d0 100644
--- a/tests/test_charm.py
+++ b/tests/test_charm.py
@@ -340,6 +340,32 @@ class TestCharm(unittest.TestCase):
         harness.update_config(config)
         expected = {
             'NGINX_BACKEND': 'http://mybackend.local:80',
+            'NGINX_CACHE_ALL': '',
+            'NGINX_CACHE_INACTIVE_TIME': '10m',
+            'NGINX_CACHE_MAX_SIZE': '10G',
+            'NGINX_CACHE_PATH': CACHE_PATH,
+            'NGINX_CACHE_USE_STALE': 'error timeout updating http_500 http_502 http_503 http_504',
+            'NGINX_CACHE_VALID': '200 1h',
+            'NGINX_CLIENT_MAX_BODY_SIZE': '1m',
+            'NGINX_KEYS_ZONE': '39c631ffb52d-cache',
+            'NGINX_SITE_NAME': 'mysite.local',
+        }
+        expected.update(JUJU_ENV_CONFIG)
+        self.assertEqual(harness.charm._make_pod_config(), expected)
+
+    def test_make_pod_config_cache_all(self):
+        """Test make_pod_config with charm config cache_all, ensure envConfig returned is correct."""
+        harness = self.harness
+
+        harness.disable_hooks()
+        harness.begin()
+
+        config = copy.deepcopy(BASE_CONFIG)
+        config['cache_all'] = True
+        harness.update_config(config)
+        expected = {
+            'NGINX_BACKEND': 'http://mybackend.local:80',
+            'NGINX_CACHE_ALL': 'proxy_ignore_headers Cache-Control Expires;',
             'NGINX_CACHE_INACTIVE_TIME': '10m',
             'NGINX_CACHE_MAX_SIZE': '10G',
             'NGINX_CACHE_PATH': CACHE_PATH,
@@ -364,6 +390,7 @@ class TestCharm(unittest.TestCase):
         harness.update_config(config)
         expected = {
             'NGINX_BACKEND': 'http://mybackend.local:80',
+            'NGINX_CACHE_ALL': '',
             'NGINX_CACHE_INACTIVE_TIME': '10m',
             'NGINX_CACHE_MAX_SIZE': '10G',
             'NGINX_CACHE_PATH': CACHE_PATH,