Merge simplestreams:drop-py2-packages into simplestreams:master

[Dan Watkins]

tools/js2signed: change shebang to /usr/bin/env python3

Previously it was using Python 2. This change is to enable Python
3-only package builds.

[Dan Watkins (oddbloke)]

As there are git repo consumers that use this repo in a Python 2-only environment, this is just the minimal change to fix package builds.

Converting the upstream away from Python 2 is a larger piece of work (which has an internal dependency), which is why I've left those as-is for now.

[Server Team CI bot (server-team-bot)]

FAILED: Continuous integration, rev:9318ca0b469ac392b1d062ee58bbc104c281e056
https://jenkins.ubuntu.com/server/job/simplestreams-ci/111/
Executed test runs:
    FAILURE: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-amd64/111/
    FAILURE: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-ppc64el/111/
    FAILURE: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-s390x/111/

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review: Needs Fixing (continuous-integration)

[Scott Moser (smoser)]

You really should fix
 tests/httpserver.py
 tools/j2signed
 tools/make-test-data

having '#!/usr/bin/python' or '#!/usr/bin/env python' is really just making things very unclear, and waiting for something to fail.

you can look at something like 'py2or3' that curtin uses, or the more over-engineered version at https://gist.github.com/smoser/8904199bb8f00a90dd04 .

its a real pain. I'm not sure how other things solve this.

If its acceptable to just drop python2 from all shebangs, then thats probably the easiest thing.

[Dan Watkins (oddbloke)]

As I said in my previous comment, I'm making the minimal change required to get package builds working. We know that there will be additional work required to fully move to Python 3, which (IIRC) we have scheduled for this cycle.

8995610... by Dan Watkins on 2019-11-26

enable tox to specify the Python version to use in sign-examples

The shebang of js2signed has been updated to Python 3, which means that
sign-examples now runs it using Python 3 by default. sign-examples is
used to setup the tox tests, which means that this change caused the
Python 2 tox environment to fail. As sign-examples is a shell wrapper
for the js2signed Python script, we can't simply invoke it using the
correct Python executable. So, instead, we add the SS_PYTHON
environment variable which allows us to specify which Python executable
to use (whilst still defaulting to using the default shebang if it isn't
set).

[Server Team CI bot (server-team-bot)]

PASSED: Continuous integration, rev:8995610594fa8adb7ab974603708eadd138733af
https://jenkins.ubuntu.com/server/job/simplestreams-ci/112/
Executed test runs:
    SUCCESS: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-amd64/112/
    SUCCESS: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-ppc64el/112/
    SUCCESS: https://jenkins.ubuntu.com/server/job/simplestreams-ci/nodes=metal-s390x/112/

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review: Approve (continuous-integration)

[Pat Viafore (patviafore)]

I think at this point all of our tools can take this change, so we're good to go.

review: Approve

[Robert C Jennings (rcj)]

+1. Patrick changed calling code to explicitly call js2signed with the python2 interpreter where that is still necessary, and that is all complete. I doubled checked his work and checked an environment he does not yet have access to. Thank you Dan.

review: Approve

diff --git a/tools/js2signed b/tools/js2signed
index b02054b..2b66e5f 100755
--- a/tools/js2signed
+++ b/tools/js2signed
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #   Copyright (C) 2013 Canonical Ltd.
 #
 #   Author: Scott Moser <[e-mail]>
diff --git a/tools/sign-examples b/tools/sign-examples
index 9b549d2..89d5dd8 100755
--- a/tools/sign-examples
+++ b/tools/sign-examples
@@ -6,4 +6,4 @@ FILES=( ${TOP_DIR}/examples/*/streams/v1/*.json )
 force=""
 [ "$1" = "--force" ] && force="$1"
 
-"${TOP_DIR}/tools/js2signed" $force "${FILES[@]}"
+$SS_PYTHON "${TOP_DIR}/tools/js2signed" $force "${FILES[@]}"
diff --git a/tox.ini b/tox.ini
index 654652e..3c8634f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,7 @@ envlist = py27, py3, flake8
 [testenv]
 setenv =
    GNUPGHOME={toxinidir}/gnupg
+   SS_PYTHON={envpython}
 commands = 
     {toxinidir}/tools/create-gpgdir
     {toxinidir}/tools/sign-examples