[vpython] Verify environment, named installs.

[vpython] Verify environment, named installs.

Support installation of named enviornments, which are VirtualEnv whose
name is explicitly specified instead of implicitly inferred from the
supplied hash. This can be used by systems that want to use "vpython" to
bootstrap a VirtualEnv in a known place instead of default usage.

Since the specification is no longer always derived from the name, we
add a step to verify that a given VirtualEnv actally matches the
expected VirutalEnv. If it doesn't, it's considered incomplete and
reprovisioned. This allows a path to upgrade named "vpython" roots from
one installation to another, as well as additional cheap sanity checking
to the basic "vpython" assumption that a stamped VirtualEnv is complete.

BUG=None
TEST=local
  - Ran "install" and setup normally, appears to work.

R=sergeyberezin@chromium.org

Review-Url: https://codereview.chromium.org/2918623003
Committed: https://github.com/luci/luci-go/commit/7303ecf220ab1d616da726f99bf70116bd07eec6

[Sergey Berezin, 2017-05-31 19:34:48]

LGTM, thanks!

[dnj, 2017-05-31 20:45:37]

The CQ bit was checked by dnj@chromium.org

[commit-bot: I haz the power, 2017-05-31 20:45:45]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-31 20:52:44]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1496263537588730, "parent_rev":
"e6b32875ab0fafb2427a92412750a3071be3fc60", "commit_rev":
"7303ecf220ab1d616da726f99bf70116bd07eec6"}

[commit-bot: I haz the power, 2017-05-31 20:52:47]

Description was changed from

==========
[vpython] Verify environment, named installs.

Support installation of named enviornments, which are VirtualEnv whose
name is explicitly specified instead of implicitly inferred from the
supplied hash. This can be used by systems that want to use "vpython" to
bootstrap a VirtualEnv in a known place instead of default usage.

Since the specification is no longer always derived from the name, we
add a step to verify that a given VirtualEnv actally matches the
expected VirutalEnv. If it doesn't, it's considered incomplete and
reprovisioned. This allows a path to upgrade named "vpython" roots from
one installation to another, as well as additional cheap sanity checking
to the basic "vpython" assumption that a stamped VirtualEnv is complete.

BUG=None
TEST=local
  - Ran "install" and setup normally, appears to work.

R=sergeyberezin@chromium.org
==========

to

==========
[vpython] Verify environment, named installs.

Support installation of named enviornments, which are VirtualEnv whose
name is explicitly specified instead of implicitly inferred from the
supplied hash. This can be used by systems that want to use "vpython" to
bootstrap a VirtualEnv in a known place instead of default usage.

Since the specification is no longer always derived from the name, we
add a step to verify that a given VirtualEnv actally matches the
expected VirutalEnv. If it doesn't, it's considered incomplete and
reprovisioned. This allows a path to upgrade named "vpython" roots from
one installation to another, as well as additional cheap sanity checking
to the basic "vpython" assumption that a stamped VirtualEnv is complete.

BUG=None
TEST=local
  - Ran "install" and setup normally, appears to work.

R=sergeyberezin@chromium.org

Review-Url: https://codereview.chromium.org/2918623003
Committed:
https://github.com/luci/luci-go/commit/7303ecf220ab1d616da726f99bf70116bd07eec6
==========

[commit-bot: I haz the power, 2017-05-31 20:52:48]

Committed patchset #1 (id:1) as
https://github.com/luci/luci-go/commit/7303ecf220ab1d616da726f99bf70116bd07eec6