Update Fedora AMI (#7102)

Fixes #6955.

This updates the Fedora version used in our test farm tests to Fedora 30. The AMI ID comes from https://alt.fedoraproject.org/cloud/ where it is listed as their standard HVM AMI for the region we use us-east-1 (US East (N. Virginia)).

Unfortunately, there were a lot of small changes required for this. The big reason for this is on Fedora, there isn't a Python 2 executable installed. In fact, there's not even an executable named python. It's just python3. Rather than installing another Python in each test, I wrote a script that the test scripts can share to figure out the different paths and names that should be used in their script. (This isn't used in test_sdists.sh because the logic is a little different.)

Other changes here worth flagging are:

I changed the name of the variable RUN_PYTHON3_TESTS in test_leauto_upgrades.sh to RUN_RHEL6_TESTS. The tests that are run when this variable is set test the upgrade from Python 2 to Python 3 on RHEL 6. I think this new name is much better now that we also have Fedora running Python 3.
I made tools/simple_http_server.py work on Python 3.
You can see tests passing with these changes at https://travis-ci.com/certbot/certbot/builds/113821476. I also ran test_tests.sh and they passed.

* Update to Fedora 30 in test farm tests.

Fedora 28 is likely to reach its EOL soon.

* Add set_python_envvars.sh.

* Fix test_apache2.sh on python3 only distros.

* Fix test_leauto_upgrades.sh on python3 systems.

* Fix certonly_standalone tests with python3 only

* Fix test_sdists.sh on python3 only distros.

* Make simple_http_server.py work on Python 3.

* add comments

tests/letstest/apache2_targets.yaml

@@ -40,8 +40,8 @@ targets:
     user: admin
   #-----------------------------------------------------------------------------
   # Fedora
-  - ami: ami-5c69df23
-    name: fedora28
+  - ami: ami-00bbc6858140f19ed
+    name: fedora30
     type: centos
     virt: hvm
     user: fedora

tests/letstest/scripts/set_python_envvars.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# This is a simple script that can be sourced to set Python environment
+# variables for use in Certbot's letstest test farm tests.
+
+# Some distros like Fedora may only have an executable named python3 installed.
+if command -v python; then
+    PYTHON_NAME="python"
+    VENV_SCRIPT="tools/venv.py"
+    VENV_PATH="venv"
+else
+    # We could check for "python2" here, however, the addition of "python3"
+    # only systems is what necessitated this change so checking for "python2"
+    # isn't necessary.
+    PYTHON_NAME="python3"
+    VENV_PATH="venv3"
+    VENV_SCRIPT="tools/venv3.py"
+fi

tests/letstest/scripts/test_apache2.sh

@@ -45,8 +45,13 @@ if [ $? -ne 0 ] ; then
     exit 1
 fi
 
-python tools/venv.py -e acme[dev] -e .[dev,docs] -e certbot-apache
-sudo venv/bin/certbot -v --debug --text --agree-dev-preview --agree-tos \
+# This script sets the environment variables PYTHON_NAME, VENV_PATH, and
+# VENV_SCRIPT based on the version of Python available on the system. For
+# instance, Fedora uses Python 3 and Python 2 is not installed.
+. tests/letstest/scripts/set_python_envvars.sh
+
+"$VENV_SCRIPT" -e acme[dev] -e .[dev,docs] -e certbot-apache
+sudo "$VENV_PATH/bin/certbot" -v --debug --text --agree-dev-preview --agree-tos \
                    --renew-by-default --redirect --register-unsafely-without-email \
                    --domain $PUBLIC_HOSTNAME --server $BOULDER_URL
 if [ $? -ne 0 ] ; then
@@ -55,7 +60,7 @@ fi
 
 if [ "$OS_TYPE" = "ubuntu" ] ; then
     export SERVER="$BOULDER_URL"
-    venv/bin/tox -e apacheconftest
+    "$VENV_PATH/bin/tox" -e apacheconftest
 else
     echo Not running hackish apache tests on $OS_TYPE
 fi

tests/letstest/scripts/test_leauto_upgrades.sh

@@ -21,7 +21,7 @@ if command -v python && [ $(python -V 2>&1 | cut -d" " -f 2 | cut -d. -f1,2 | se
     # 0.20.0 is the latest version of letsencrypt-auto that doesn't install
     # Python 3 on RHEL 6.
     INITIAL_VERSION="0.20.0"
-    RUN_PYTHON3_TESTS=1
+    RUN_RHEL6_TESTS=1
 else
     # 0.33.x is the oldest version of letsencrypt-auto that works on Fedora 29+.
     INITIAL_VERSION="0.33.1"
@@ -32,14 +32,19 @@ if ! ./letsencrypt-auto -v --debug --version --no-self-upgrade 2>&1 | tail -n1 |
     exit 1
 fi
 
+# This script sets the environment variables PYTHON_NAME, VENV_PATH, and
+# VENV_SCRIPT based on the version of Python available on the system. For
+# instance, Fedora uses Python 3 and Python 2 is not installed.
+. tests/letstest/scripts/set_python_envvars.sh
+
 # Now that python and openssl have been installed, we can set up a fake server
 # to provide a new version of letsencrypt-auto. First, we start the server and
 # directory to be served.
 MY_TEMP_DIR=$(mktemp -d)
 PORT_FILE="$MY_TEMP_DIR/port"
-SERVER_PATH=$(tools/readlink.py tools/simple_http_server.py)
+SERVER_PATH=$("$PYTHON_NAME" tools/readlink.py tools/simple_http_server.py)
 cd "$MY_TEMP_DIR"
-"$SERVER_PATH" 0 > $PORT_FILE &
+"$PYTHON_NAME" "$SERVER_PATH" 0 > $PORT_FILE &
 SERVER_PID=$!
 trap 'kill "$SERVER_PID" && rm -rf "$MY_TEMP_DIR"' EXIT
 cd ~-
@@ -72,7 +77,7 @@ iQIDAQAB
 -----END PUBLIC KEY-----
 "
 
-if [ "$RUN_PYTHON3_TESTS" = 1 ]; then
+if [ "$RUN_RHEL6_TESTS" = 1 ]; then
     if command -v python3; then
         echo "Didn't expect Python 3 to be installed!"
         exit 1
@@ -110,7 +115,7 @@ if ! diff letsencrypt-auto letsencrypt-auto-source/letsencrypt-auto ; then
     exit 1
 fi
 
-if [ "$RUN_PYTHON3_TESTS" = 1 ]; then
+if [ "$RUN_RHEL6_TESTS" = 1 ]; then
     if ! command -v python3; then
         echo "Python3 wasn't properly installed"
         exit 1
@@ -120,7 +125,7 @@ if [ "$RUN_PYTHON3_TESTS" = 1 ]; then
         exit 1
     fi
 
-    if [ "$(tools/readlink.py $OLD_VENV_PATH)" != "/opt/eff.org/certbot/venv" ]; then
+    if [ "$("$PYTHON_NAME" tools/readlink.py $OLD_VENV_PATH)" != "/opt/eff.org/certbot/venv" ]; then
         echo symlink from old venv path not properly created!
         exit 1
     fi

tests/letstest/scripts/test_letsencrypt_auto_certonly_standalone.sh

@@ -18,6 +18,11 @@ export PATH="$LE_AUTO_DIR:$PATH"
 
 letsencrypt-auto --os-packages-only --debug --version
 
+# This script sets the environment variables PYTHON_NAME, VENV_PATH, and
+# VENV_SCRIPT based on the version of Python available on the system. For
+# instance, Fedora uses Python 3 and Python 2 is not installed.
+. tests/letstest/scripts/set_python_envvars.sh
+
 # Create a venv-like layout at the old virtual environment path to test that a
 # symlink is properly created when letsencrypt-auto runs.
 HOME=${HOME:-~root}
@@ -32,7 +37,8 @@ letsencrypt-auto certonly --no-self-upgrade -v --standalone --debug \
                    --register-unsafely-without-email \
                    --domain $PUBLIC_HOSTNAME --server $BOULDER_URL
 
-if [ "$(tools/readlink.py ${XDG_DATA_HOME:-~/.local/share}/letsencrypt)" != "/opt/eff.org/certbot/venv" ]; then
+LINK_PATH=$("$PYTHON_NAME" tools/readlink.py ${XDG_DATA_HOME:-~/.local/share}/letsencrypt)
+if [ "$LINK_PATH" != "/opt/eff.org/certbot/venv" ]; then
     echo symlink from old venv path not properly created!
     exit 1
 fi

tests/letstest/scripts/test_sdists.sh

@@ -6,16 +6,20 @@ cd letsencrypt
 PLUGINS="certbot-apache certbot-nginx"
 PYTHON_MAJOR_VERSION=$(/opt/eff.org/certbot/venv/bin/python --version 2>&1 | cut -d" " -f 2 | cut -d. -f1)
 TEMP_DIR=$(mktemp -d)
-VERSION=$(letsencrypt-auto-source/version.py)
 
 if [ "$PYTHON_MAJOR_VERSION" = "3" ]; then
+    # Some distros like Fedora may only have an executable named python3 installed.
+    PYTHON_NAME="python3"
     VENV_PATH="venv3"
     VENV_SCRIPT="tools/venv3.py"
 else
+    PYTHON_NAME="python"
     VENV_SCRIPT="tools/venv.py"
     VENV_PATH="venv"
 fi
 
+VERSION=$("$PYTHON_NAME" letsencrypt-auto-source/version.py)
+
 # setup venv
 "$VENV_SCRIPT" --requirement letsencrypt-auto-source/pieces/dependency-requirements.txt
 . "$VENV_PATH/bin/activate"

tests/letstest/targets.yaml

@@ -49,8 +49,8 @@ targets:
     type: centos
     virt: hvm
     user: ec2-user
-  - ami: ami-5c69df23
-    name: fedora28
+  - ami: ami-00bbc6858140f19ed
+    name: fedora30
     type: centos
     virt: hvm
     user: fedora