Configurable app base directory

* Replace hardcoded instances of /opt/wwc with $app_base_dir, which
  defaults to /opt/wwc.
* Add tags to nginx tasks so they can be selected independently.

playbooks/group_vars/all

+---
+app_base_dir: /opt/wwc

playbooks/roles/common/tasks/main.yml

@@ -2,7 +2,7 @@
 - include: create_users.yml
 - name: Create application root
   sudo: True
-  file: path=/opt/wwc state=directory owner=root group=root
+  file: path=$app_base_dir state=directory owner=root group=root
 - name: Create log directory
   sudo: True
   file: path=/mnt/logs state=directory

playbooks/roles/common/vars/main.yml

@@ -9,8 +9,8 @@ nginx_cfg:
     edx_release: link
   # path to version files for the basic
   # nginx configuration
-  version_html: /opt/wwc/versions.html
-  version_json: /opt/wwc/versions.json
+  version_html: $app_base_dir/versions.html
+  version_json: $app_base_dir/versions.json
   # default htpasswd contents set to edx/edx
   # this value can be overiden in vars/secure/<group>.yml
   htpasswd: |

playbooks/roles/lms/tasks/main.yml

@@ -3,11 +3,11 @@
 #  - nginx/tasks/main.yml
 ---
 - name: create lms application config
-  template: src=env.json.j2 dest=/opt/wwc/lms.env.json
+  template: src=env.json.j2 dest=$app_base_dir/lms.env.json
   sudo: True
 
 - name: create lms auth file
-  template: src=auth.json.j2 dest=/opt/wwc/lms.auth.json
+  template: src=auth.json.j2 dest=$app_base_dir/lms.auth.json
   sudo: True
 
 - include: ../../nginx/tasks/nginx_site.yml state=link site_name=lms
@@ -22,13 +22,13 @@
 - name: install read-only ssh key for mitx repo (host github known)
   copy: src=vars/secure/ssh_deploy_known_hosts dest=/home/ubuntu/.ssh/known_hosts force=yes owner=ubuntu group=ubuntu mode=600
 
-# Check out mitx repo to /opt/wwc
-- name: set permissions on /opt/wwc sgid for edx
-  file: path=/opt/wwc owner=root group=edx mode=2775 state=directory
-  file: path=/opt/wwc/mitx owner=ubuntu group=edx mode=2775 state=directory
+# Check out mitx repo to $app_base_dir
+- name: set permissions on $app_base_dir sgid for edx
+  file: path=$app_base_dir owner=root group=edx mode=2775 state=directory
+  file: path=$app_base_dir owner=ubuntu group=edx mode=2775 state=directory
   sudo: True
 - name: install git and its recommends
   apt: pkg=git state=installed install_recommends=yes 
   sudo: True
-- name: git checkout mitx repo into /opt/wwc
-  git: dest=/opt/wwc/mitx repo=git@github.com:MITx/mitx.git
+- name: git checkout mitx repo into $app_base_dir
+  git: dest=$app_base_dir/mitx repo=git@github.com:MITx/mitx.git

playbooks/roles/nginx/tasks/main.yml

@@ -5,11 +5,15 @@
   sudo: True
   apt: pkg=nginx state={{ pkgs.nginx.state }}
   notify: restart nginx
+  tags:
+  - nginx
 # removing default link
 - name: Removing default nginx config
   sudo: True
   file: path=/etc/nginx/sites-available/default state=absent
   notify: restart nginx
+  tags:
+  - nginx
 # Standard configuration that is common across all roles
 # Default values for these variables are set in group_vars/all
 # Note: remove spaces in {{..}}, otherwise you will get a template parsing error.
@@ -18,6 +22,10 @@
 # Default htpassword file, required for basic auth
 - copy: content={{ nginx_cfg.htpasswd }} dest=/etc/nginx/nginx.htpasswd
   sudo: True
+  tags:
+  - nginx
 - name: Ensuring that nginx is running
   sudo: True
   service: name=nginx state=started
+  tags:
+  - nginx

playbooks/roles/nginx/tasks/nginx_site.yml

@@ -4,8 +4,12 @@
   sudo: True
   template: src={{ site_name }}.j2 dest=/etc/nginx/sites-available/{{ site_name }}
   notify: restart nginx
+  tags:
+  - nginx
 
 - name: Creating nginx config link {{ site_name }}
   sudo: True
   file: src=/etc/nginx/sites-available/{{ site_name }} dest=/etc/nginx/sites-enabled/{{ site_name }} state={{ state }} owner=root group=root
   notify: restart nginx
+  tags:
+  - nginx

playbooks/roles/nginx/templates/basic-auth.j2

@@ -3,7 +3,7 @@ server {
   location / {
      auth_basic            "Restricted";
      auth_basic_user_file  /etc/nginx/nginx.htpasswd;
-     root /opt/wwc/main_static;
+     root {{app_base_dir}}/main_static;
      index index.html
      proxy_set_header X-Forwarded-Proto https;
   }

playbooks/roles/nginx/templates/lms.j2

 server {
+  # LMS configuration file for nginx, templated by ansible
 
   listen 80;
 
@@ -65,7 +66,7 @@ server {
   location ~ /static/(?P<file>.*) {
     auth_basic            "Restricted";
     auth_basic_user_file  /etc/nginx/lms.htpasswd;
-    root /opt/wwc;
+    root {{app_base_dir}};
     try_files /staticfiles/$file /course_static/$file =404;
 
     # return a 403 for static files that shouldn't be