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

[Haw Loeung]

Allow overriding backend/proxy path

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

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

[Joel Sing (jsing)]

LGTM, see comments inline.

review: Approve (+1)

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

Merge proposal is approved, but source revision has changed, setting status to needs review.

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

Change successfully merged at revision 4b43be183bfb3670d2ea4ad4acd0ad13b37e274e

diff --git a/lib/utils.py b/lib/utils.py
index e1288e4..cff2405 100644
--- a/lib/utils.py
+++ b/lib/utils.py
@@ -57,3 +57,13 @@ def generate_token(signing_secret, url_path, expiry_time):
     digest = hmac.new(signing_secret.encode(), string_to_sign.encode(),
                       hashlib.sha1)
     return "{0}_{1}".format(expiration, digest.hexdigest())
+
+
+def generate_uri(host, port=80, path=None, scheme='http'):
+    if not path:
+        path = ''
+    # XXX: Fix to handle if host is an IPv6 literal
+    if path and not path.startswith('/'):
+        path = '/{}'.format(path)
+    uri = '{scheme}://{host}:{port}{path}'.format(scheme=scheme, host=host, port=port, path=path)
+    return uri
diff --git a/reactive/content_cache.py b/reactive/content_cache.py
index 7f4f3a3..6ab5eb3 100644
--- a/reactive/content_cache.py
+++ b/reactive/content_cache.py
@@ -103,7 +103,8 @@ def configure_nginx(conf_path=None):
 
             backend_port = loc_conf.get('backend_port')
             if backend_port:
-                lc['backend'] = 'http://localhost:{}'.format(backend_port)
+                backend_path = loc_conf.get('backend-path')
+                lc['backend'] = utils.generate_uri('localhost', backend_port, backend_path)
 
             # Per site secret HMAC key, if it exists. We pass this through to
             # the caching layer to activate the bit to restrict access.
diff --git a/tests/unit/files/config_test_config.txt b/tests/unit/files/config_test_config.txt
index e074496..9b29970 100644
--- a/tests/unit/files/config_test_config.txt
+++ b/tests/unit/files/config_test_config.txt
@@ -66,3 +66,4 @@ site5:
       modifier: '='
       backends:
         - 127.0.1.11:80
+      backend-path: /auth-check/
diff --git a/tests/unit/files/nginx_config_rendered_test_output-site5.txt b/tests/unit/files/nginx_config_rendered_test_output-site5.txt
index 9425247..8827016 100644
--- a/tests/unit/files/nginx_config_rendered_test_output-site5.txt
+++ b/tests/unit/files/nginx_config_rendered_test_output-site5.txt
@@ -18,7 +18,7 @@ server {
 
 
     location = /auth {
-        proxy_pass http://localhost:8084;
+        proxy_pass http://localhost:8084/auth-check/;
         proxy_set_header Host "site5.local";
         proxy_cache site5-cache;
         proxy_cache_background_update on;
diff --git a/tests/unit/test_nginx.py b/tests/unit/test_nginx.py
index a58ef7e..31d6a9e 100644
--- a/tests/unit/test_nginx.py
+++ b/tests/unit/test_nginx.py
@@ -7,6 +7,7 @@ import yaml
 
 sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(os.path.realpath(__file__)))))
 from lib import nginx  # NOQA: E402
+from lib import utils  # NOQA: E402
 
 BASE_LISTEN_PORT = 6080
 BASE_BACKEND_PORT = 8080
@@ -59,7 +60,8 @@ class TestLibNginx(unittest.TestCase):
 
                 if loc_conf.get('backends'):
                     backend_port += 1
-                    lc['backend'] = 'http://localhost:{}'.format(backend_port)
+                    backend_path = loc_conf.get('backend-path')
+                    lc['backend'] = utils.generate_uri('localhost', backend_port, backend_path)
 
                 lc['signed-url-hmac-key'] = loc_conf.get('signed-url-hmac-key')
                 lc['origin-headers'] = loc_conf.get('origin-headers')
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 89604c8..8a0fd9c 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -68,3 +68,10 @@ class TestLibUtils(unittest.TestCase):
         expiry_time = datetime.datetime.now() + datetime.timedelta(days=1)
         want = '1553299200_d5257bb9f1e5e27065f2e7c986ca8c95f4cc3680'
         self.assertEqual(utils.generate_token(signing_key, '/', expiry_time), want)
+
+    def test_generate_uri(self):
+        self.assertEqual(utils.generate_uri('localhost'), 'http://localhost:80')
+        self.assertEqual(utils.generate_uri('localhost', 8080), 'http://localhost:8080')
+        self.assertEqual(utils.generate_uri('localhost', path='mypath'), 'http://localhost:80/mypath')
+        self.assertEqual(utils.generate_uri('localhost', path='/mypath'), 'http://localhost:80/mypath')
+        self.assertEqual(utils.generate_uri('10.0.0.1', path='/mypath'), 'http://10.0.0.1:80/mypath')