From 613713b7945f1c06b7bc0e2fbae2e6f4f637f059 Mon Sep 17 00:00:00 2001
From: Alex Goodman <alex@prefect.io>
Date: Tue, 22 Oct 2019 15:30:34 -0400
Subject: [PATCH] only allow docker builds for tagged commits on master

---
 .circleci/config.yml                       | 14 +++++++++++---
 src/prefect/environments/storage/docker.py |  1 -
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index f40341f04590..f3492a362c6e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -281,6 +281,14 @@ jobs:
       PYTHON_TAG: python<< parameters.python-version >>
     steps:
       - checkout
+      - run:
+          name: Master branch check
+          command: |
+            apk add git
+            if [[ $(git branch --contains $CIRCLE_SHA1 --points-at master | wc -l) -ne 1 ]]; then
+              echo "commit $CIRCLE_SHA1 is not a member of the master branch"
+              exit 1
+            fi
       - setup_remote_docker:
           docker_layer_caching: true
       - run:
@@ -350,14 +358,14 @@ workflows:
           python-version: "3.5"
           filters:
             branches:
-              only: master
+              ignore: /.*/
             tags:
               only: /^[0-9]+\.[0-9]+\.[0-9]+$/
       - build-docker-image:
           python-version: "3.6"
           filters:
             branches:
-              only: master
+              ignore: /.*/
             tags:
               only: /^[0-9]+\.[0-9]+\.[0-9]+$/
       - build-docker-image:
@@ -365,6 +373,6 @@ workflows:
           tag-latest: true
           filters:
             branches:
-              only: master
+              ignore: /.*/
             tags:
               only: /^[0-9]+\.[0-9]+\.[0-9]+$/
\ No newline at end of file
diff --git a/src/prefect/environments/storage/docker.py b/src/prefect/environments/storage/docker.py
index 31251c946c4a..0f86ad286306 100644
--- a/src/prefect/environments/storage/docker.py
+++ b/src/prefect/environments/storage/docker.py
@@ -95,7 +95,6 @@ def __init__(
                 sys.version_info.major, sys.version_info.minor
             )
             if re.match("^[0-9]+\.[0-9]+\.[0-9]+$", self.prefect_version) != None:
-                # note: this does not necessarily mean that we have built/pushed all previous prefect versions to dockerhub
                 self.base_image = "prefecthq/prefect:{}-python{}".format(
                     self.prefect_version, python_version
                 )