Remove python2 from CI.

etc/taskcluster/decisionlib.py

@@ -623,27 +623,6 @@ class WindowsGenericWorkerTask(GenericWorkerTask):
         .with_dependencies(repack_task) \
         .with_directory_mount("public/repacked.zip", task_id=repack_task, path=path)
 
-    def with_python2(self):
-        """
-        Make Python 2, pip, and virtualenv accessible to the task’s commands.
-
-        For Python 3, use `with_directory_mount` and the "embeddable zip file" distribution
-        from python.org.
-        You may need to remove `python37._pth` from the ZIP in order to work around
-        <https://bugs.python.org/issue34841>.
-        """
-        return self \
-        .with_repacked_msi(
-            "https://www.python.org/ftp/python/2.7.15/python-2.7.15.amd64.msi",
-            sha256="5e85f3c4c209de98480acbf2ba2e71a907fd5567a838ad4b6748c76deb286ad7",
-            path="python2"
-        ) \
-        .with_early_script("""
-            python -m ensurepip
-            pip install virtualenv==16.0.0
-        """) \
-        .with_path_from_homedir("python2", "python2\\Scripts")
-
     def with_python3(self):
         """
         For Python 3, use `with_directory_mount` and the "embeddable zip file" distribution
@@ -719,13 +698,6 @@ class MacOsGenericWorkerTask(UnixTaskMixin, GenericWorkerTask):
             ]
         ]
 
-    def with_python2(self):
-        return self.with_early_script("""
-            export PATH="$HOME/Library/Python/2.7/bin:$PATH"
-            python -m ensurepip --user
-            pip install --user virtualenv
-        """)
-
     def with_python3(self):
         return self.with_early_script("""
             python3 -m ensurepip --user

etc/taskcluster/docker/base.dockerfile

@@ -17,11 +17,6 @@ RUN \
         git \
         ca-certificates \
         #
-        # Running mach with Python 2
-        python2 \
-        python2-dev \
-        python-is-python2 \
-        #
         # Running mach with Python 3
         python3 \
         python3-pip \
@@ -35,12 +30,4 @@ RUN \
         curl \
         # Setting the default locale
         locales \
-        locales-all \
+        locales-all
-    && \
-    #
-    # Python 2 bits that have been removed from Ubuntu packages
-    curl https://bootstrap.pypa.io/2.7/get-pip.py -sSf -o get-pip.py && \
-    python2 get-pip.py && \
-    python2 -m pip install virtualenv && \
-    # Ensure modern pip is present.
-    python3 -m pip install -U pip