add indirection to allow providing basic auth to proxy

Author: sjpb

environments/common/inventory/group_vars/all/proxy.yml

@@ -1,2 +1,17 @@
-# default proxy address to first squid api address port 3128 if squid group non-empty, else empty string to avoid breaking hostvars
-proxy_http_proxy: "{{ 'http://' + hostvars[groups['squid'].0].api_address + ':' + (squid_http_port | string) if groups['squid'] else '' }}"
+# default proxy address to hostname of first squid host, port 3128
+# if squid group non-empty, else else empty string to avoid breaking hostvars
+
+# override these to provide basic_auth:
+proxy_basic_user: ''
+proxy_basic_password: ''
+
+# some indirection to make this logic easier:
+proxy_http_address: "{{ hostvars[groups['squid'].0].api_address }}"
+proxy_http_port: "{{ squid_http_port }}"
+proxy_basic_auth: "{{ proxy_basic_user }}:{{ proxy_basic_password }}@"
+proxy_http_proxy_default: >-
+  {{ 'http://' +
+     (proxy_basic_auth if proxy_basic_password != '' else '') +
+     proxy_http_address + ':' + (proxy_http_port | string)
+  }}
+proxy_http_proxy: "{{ proxy_http_proxy_default if groups['squid'] else '' }}"