Added alert to admin interface of instances still on Trusty after Mar 4

[zenmonkeykstop]

Status

Ready for review

Description of Changes

Fixes #4027. Adds a red bar at the top of the page for logged-in users of the Journalist Interface, warning them that their instance's server OS is EOL and must be upgraded. This message only appears if the system date is Mar 4 2019 or later and the OS version string is not "16.04"

Visually, the bar element should match the mockup in #4027 with the exception of the shade of red used - as coded, it uses the red warning color predefined in the application's stylesheets.

Testing

Testing in a development environment

The date for the alert to start appearing, and the OS version to test for, are set in journalist_app/__init__.py:

XENIAL_WARNING_DATE = datetime.strptime('Mar 4 2019', '%b %d %Y'),      
XENIAL_VER = '16.04'   

The simplest way to test the alert behaviour is to modify these config settings and restart the Journalist Interface application.

• Set XENIAL_WARNING_DATE to tomorrow, and verify that the alert is NOT displayed
• Set XENIAL_WARNING_DATE to tomorrow and XENIAL_VER to "14.04", and verify that the alert is NOT displayed
• Set XENIAL_WARNING_DATE to yesterday and XENIAL_VER to "14.04", and verify that the alert is NOT displayed
• Set XENIAL_WARNING_DATE to yesterday and XENIAL_VER to "16.04", and verify that the alert is displayed

Testing in staging

• Modify the XENIAL_WARNING_DATE in securedrop/journalist_app/__init__.py to yesterday, and create a (Trusty) staging environment with make build-debs && make staging. Verify that the warning is displayed
• Modify the XENIAL_WARNING_DATE in securedrop/journalist_app/__init__.py to yesterday, and create a (Trusty) staging environment with `make build-debs && make staging. Verify that the warning is displayed.
• Modify the XENIAL_WARNING_DATE in securedrop/journalist_app/__init__.py to yesterday, and create a (Trusty) staging environment with make build-debs && molecule converge -s libvirt-staging-xenial. Verify that the warning is not displayed.

Checklist

If you made changes to the server application code:

• Linting (make ci-lint) and tests (make -C securedrop test) pass in the development container

If you made non-trivial code changes:

• I have written a test plan and validated it for this PR

[kushaldas]

The bar looks very nice. But, in my case, both Xenial and Trusty is showing me the bar. Can anyone also please double check this?

[zenmonkeykstop]

@kushaldas apologies, was getting caught out by apparmor rules - works now.

[kushaldas]

Now things are working as intended. I will wait for others to approve the text in the banner though.

[emkll]

Thanks @zenmonkeykstop this looks great. Functional testing in staging VM looks good to me, the apparmor profiles seem to work well. Otherwise, I've left a couple minor comments inline.

I'll let others chime in on the final wording, but it sounds good to me.

[heartsucker]

I ran through the full test suite for both dev and staging environments. Good to go.