ci: Remove Ubuntu 14.04 (trusty) from CI.

Tweaked by tabbott to improve our CI docs discussion of these.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

.circleci/config.yml

@@ -82,25 +82,6 @@ aliases:
          || echo "Error in uploading coverage reports to codecov.io."
 
 jobs:
-  "trusty-backend-python3.4":
-    docker:
-      # This is built from tools/circleci/images/trusty/Dockerfile .
-      # Trusty ships with Python 3.4.
-      - image: gregprice/circleci:trusty-python-5.test
-
-    working_directory: ~/zulip
-
-    steps:
-      - checkout
-
-      - *create_cache_directories
-      - *restore_cache_package_json
-      - *restore_cache_requirements
-      - *install_dependencies
-      - *save_cache_package_json
-      - *save_cache_requirements
-      - *run_backend_tests
-
   "xenial-backend-frontend-python3.5":
     docker:
       # This is built from tools/circleci/images/xenial/Dockerfile .
@@ -160,6 +141,5 @@ workflows:
   version: 2
   build:
     jobs:
-      - "trusty-backend-python3.4"
       - "xenial-backend-frontend-python3.5"
       - "bionic-backend-python3.6"

README.md

@@ -58,7 +58,7 @@ You might be interested in:
 
 * **Running a Zulip server**. Setting up a server takes just a couple
   of minutes. Zulip runs on Ubuntu 18.04 Bionic, Ubuntu 16.04 Xenial,
-  Ubuntu 14.04 Trusty, and Debian 9 Stretch. The installation process is
+  and Debian 9 Stretch. The installation process is
   [documented here](https://zulip.readthedocs.io/en/stable/production/install.html).
   Commercial support is available; see <https://zulipchat.com/plans>
   for details.

docs/testing/continuous-integration.md

@@ -52,18 +52,16 @@ uses those SSH keys for authentication.
 
 The main CircleCI configuration file is
 [./circleci/config.yml](https://github.com/zulip/zulip/blob/master/.circleci/config.yml).
-We currently run several jobs during a CircleCI build. They are:
-* trusty-python-3.4
-* xenial-python-3.5
-* bionic-python-3.6
+We run multiple jobs during a CircleCI build to test different
+supported platforms. They are currently:
+
+* xenial-backend-frontend-python-3.5
+* bionic-backend-python3.6
 
 Each runs the Zulip backend test suites, using the indicated
-platform/OS and Python version. `bionic-python-3.6` job for example
-runs the tests in Ubuntu Xenial with Python 3.6 pre-installed.
-Additionally, the `xenial` suite also runs the Zulip frontend test
-suites; since those are not platform-dependent, it doesn't make sense
-to run them on all platforms.  Your build for the PR will pass only if
-all the 3 jobs are executed successfully.
+platform/OS and Python version.  As suggested by the names, only one
+suite runs the frontend test suites, since those are not
+platform-dependent.
 
 ### Configuration
 

tools/circleci/images.yml

@@ -1,7 +1,3 @@
-trusty:
-  base_image: buildpack-deps:trusty-scm
-  extra_packages: python-virtualenv postgresql-9.3
-
 xenial:
   base_image: buildpack-deps:xenial-scm
   extra_packages: virtualenv postgresql-9.5