Add FileEntry cache to TagCache for selfupdate.

Add FileEntry cache to TagCache for selfupdate.

This adds a mapping of (instance ID, file name) -> sha1, which the selfupdater
will use to cache the hash of itself and avoid issuing redundant downloads of
the same client multiple times.

R=dnj@chromium.org, vadimsh@chromium.org
BUG=663843
Committed: https://github.com/luci/luci-go/commit/7409ae3d13816767573247cee751b0e7372ab0c2

[iannucci, 2016-11-15 23:57:23]

ping :) (dnj reviewed on the previous incarnation, but vadimsh you should take a
look)

[Vadim Sh., 2016-11-16 00:09:30]

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/client.go
File cipd/client/cipd/client.go (right):

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/client.go#...
cipd/client/cipd/client.go:683: if err := cache.AddTag(pin, version); err != nil
{
please bring back context.Context and add it to AddFile call too:
1. It makes API more consistent.
2. If context is suddenly needed later (e.g. for logging), it is available.

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
File cipd/client/cipd/internal/tagcache.go (right):

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:40: // Additionally, this TagCache stores
a mapping of hex(sha1(executable)) ->
it stores instance ID => sha1 mapping, no its reverse as in your comment

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:186: // AddFile adds an entry to the
exe_entries, mapping the given hash to the
"AddFile records that a file 'fileName' inside a package identified by
instanceID has given hash"

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:190: func (c *TagCache)
AddFile(instanceID, fileName, hash string) error {
In CIPD package model, instanceID by itself is not considered unique identifier
of a package, only a pair (packageName, instanceID) (aka common.Pin) is. The
cache should map (pin, filename) to hash.

[iannucci, 2016-11-16 00:45:12]

ptal!

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/client.go
File cipd/client/cipd/client.go (right):

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/client.go#...
cipd/client/cipd/client.go:683: if err := cache.AddTag(pin, version); err != nil
{
On 2016/11/16 00:09:29, Vadim Sh. wrote:
> please bring back context.Context and add it to AddFile call too:
> 1. It makes API more consistent.
> 2. If context is suddenly needed later (e.g. for logging), it is available.

done

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
File cipd/client/cipd/internal/tagcache.go (right):

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:40: // Additionally, this TagCache stores
a mapping of hex(sha1(executable)) ->
On 2016/11/16 00:09:29, Vadim Sh. wrote:
> it stores instance ID => sha1 mapping, no its reverse as in your comment

blar I thought I fixed this comment...

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:186: // AddFile adds an entry to the
exe_entries, mapping the given hash to the
On 2016/11/16 00:09:29, Vadim Sh. wrote:
> "AddFile records that a file 'fileName' inside a package identified by
> instanceID has given hash"

ptal

https://codereview.chromium.org/2501023002/diff/1/cipd/client/cipd/internal/t...
cipd/client/cipd/internal/tagcache.go:190: func (c *TagCache)
AddFile(instanceID, fileName, hash string) error {
On 2016/11/16 00:09:29, Vadim Sh. wrote:
> In CIPD package model, instanceID by itself is not considered unique
identifier
> of a package, only a pair (packageName, instanceID) (aka common.Pin) is. The
> cache should map (pin, filename) to hash.

Done.

[Vadim Sh., 2016-11-16 00:48:56]

lgtm

[iannucci, 2016-11-16 00:50:57]

The CQ bit was checked by iannucci@chromium.org

[commit-bot: I haz the power, 2016-11-16 00:51:08]

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, 2016-11-16 00:57:03]

Description was changed from

==========
Add FileEntry cache to TagCache for selfupdate.

This adds a mapping of (instance ID, file name) -> sha1, which the selfupdater
will use to cache the hash of itself and avoid issuing redundant downloads of
the same client multiple times.

R=dnj@chromium.org, vadimsh@chromium.org
BUG=663843
==========

to

==========
Add FileEntry cache to TagCache for selfupdate.

This adds a mapping of (instance ID, file name) -> sha1, which the selfupdater
will use to cache the hash of itself and avoid issuing redundant downloads of
the same client multiple times.

R=dnj@chromium.org, vadimsh@chromium.org
BUG=663843

Committed:
https://github.com/luci/luci-go/commit/7409ae3d13816767573247cee751b0e7372ab0c2
==========

[commit-bot: I haz the power, 2016-11-16 00:57:04]

Committed patchset #2 (id:20001) as
https://github.com/luci/luci-go/commit/7409ae3d13816767573247cee751b0e7372ab0c2