run-selenium: run selenium on a node

This runs selenium from a container on a node, and exposes port 4444
so you can issue commands to it.  This is used in the follow-on
I56cda99790d3c172e10b664e57abeca10efc5566 to take some screenshots of
gerrit.

Change-Id: Idcbcd9a8f33bd86b5f3e546dd563792212e0751b

playbooks/roles/run-selenium/README.rst

@@ -0,0 +1,6 @@
+run-selenium
+
+Run a selenium container that listens on port 4444 on a host.
+
+This is intended only for use during gate testing to capture
+screenshots from a local service.  Usually used from testinfra jobs.

playbooks/roles/run-selenium/tasks/main.yaml

@@ -0,0 +1,5 @@
+- name: Run selenium container
+  shell:
+    executable: /bin/sh
+    cmd: |
+      docker run -d --network="host" -v /dev/shm:/dev/shm selenium/standalone-firefox:4.0.0-beta-1-prerelease-20201202

playbooks/zuul/run-base.yaml

@@ -41,7 +41,11 @@
         bastion_ipv4: "{{ nodepool['public_ipv4'] }}"
         bastion_ipv6: "{{ nodepool['public_ipv6'] }}"
         bastion_public_key: "{{ lookup('file', zuul.executor.work_root + '/' + zuul.build + '_id_rsa.pub') }}"
-        iptables_test_public_tcp_ports: [19885]
+        iptables_test_public_tcp_ports:
+          # Zuul web console
+          - 19885
+          # selenium
+          - 4444
       template:
         src: "templates/{{ item }}.j2"
         dest: "/etc/ansible/hosts/{{ item }}"
@@ -107,6 +111,19 @@
         content: "{{ testinfra_extra_data | default('') | to_nice_yaml(indent=2) }}"
         dest: '/home/zuul/testinfra_extra_data_fixture.yaml'
 
+    - name: Make screenshots directory
+      file:
+        path: '/var/log/screenshots'
+        state: directory
+
+    - name: Return screenshots artifact
+      zuul_return:
+        data:
+          zuul:
+            artifacts:
+              - name: Screenshots
+                url: "bridge.openstack.org/screenshots"
+
     - name: Run and collect testinfra
       block:
         - name: Run testinfra to validate configuration

tox.ini

@@ -41,6 +41,7 @@ deps =
   ansible-base # see install-ansible/tasks/main.yaml
   pytest-html # MPL-2.0
   pytest-testinfra>=6.0.0
+  selenium
 
 # This environment assumes a gate-hosts.yaml file has been written.
 passenv =

zuul.d/system-config-run.yaml

@@ -25,6 +25,7 @@
           '{{ zuul.project.src_dir }}/junit.xml': logs
           '{{ zuul.project.src_dir }}/test-results.html': logs
           '{{ zuul.project.src_dir }}/inventory/base/gate-hosts.yaml': logs
+          '/var/log/screenshots': logs
 
 # Note: the following two jobs implement the variant-based multiple
 # inheritance trick.  Both of these variants will always apply,