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Add an API for libsolv, libdnf, et al to use to check if rpmdb has changed and trivially get path to rpmdb #388

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Conan-Kudo opened this issue Feb 1, 2018 · 1 comment · Fixed by #712
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Add an API for libsolv, libdnf, et al to use to check if rpmdb has changed and trivially get path to rpmdb #388

Conan-Kudo opened this issue Feb 1, 2018 · 1 comment · Fixed by #712
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API API related RFE

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@Conan-Kudo
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Conan-Kudo commented Feb 1, 2018 •
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Quoted from @pmatilai in rpm-software-management/libdnf#362 (comment):

Of course, libdnf is not poking at rpmdb directory just for fun, it does it to see if the rpmdb was changed since the last time. That information is something that librpm should be providing via an API. And now that this came up, I remember going through this same discussion at least twice before in the last 8-9 years but nothing ever got implemented in rpm, so my bad I guess :-/

Also quoted from @pmatilai in rpm-software-management/libdnf#362 (comment):

AFAICS libdnf does this to see if there is a valid rpmdb cache it can use, which seems fairly reasonable as such, but then libsolv also has similar logic in it. So there's probably something else to streamline etc besides rpm needing to add that rpmdb cookie API.

I'm currently beginning experiments with non-BDB rpmdb, but these assumptions made about how the rpmdb exists causes problems, as I need to patch them to "know" the alternative paths used by the different backends.

It'd be nice if there was a nice backend-agnostic set of APIs to solve these problems in libsolv, libdnf, and dnf so that this stops being a problem and even as more backends and changes to existing ones occur, everything won't break.

(Also filing this so it doesn't get forgotten again...)
@pmatilai pmatilai added the RFC label Feb 12, 2018
@pmatilai pmatilai added RFE and removed RFC labels Jun 18, 2018
@pmatilai pmatilai added the API API related label Oct 2, 2018
pmatilai added a commit to pmatilai/rpm that referenced this issue May 23, 2019
@pmatilai
Implement a database cookie API for determining whether rpmdb has cha…
177aac6 
…nged

Add rpmdbCookie() public function and matching python bindings.
The returned value is an opaque string which changes any time the rpmdb
is changed (eg packages added or removed, rebuild changes things etc).
A key point is that this is entirely database backend agnostic.

The actual implementation here is an SHA1 hash of RPMDBI_NAME keys,
but this is an implementation detail that can be changed anytime and
callers must not rely on. The only thing that matters is whether the
string equals an earlier cookie value or not. A cryptographic hash
seems like an overkill, but then it saves us the headaches of coming
up with something that reflects order changes etc.

Closes: rpm-software-management#388
@pmatilai pmatilai mentioned this issue May 23, 2019
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@pmatilai
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A simple cookie API implemented in PR #712 , comments welcome.

pmatilai added a commit to pmatilai/rpm that referenced this issue May 23, 2019
@pmatilai
Implement a database cookie API for determining whether rpmdb has cha…
83d40ef 
…nged

Add rpmdbCookie() public function and matching python bindings.
The returned value is an opaque string which changes any time the rpmdb
is changed (eg packages added or removed, rebuild changes things etc).
A key point is that this is entirely database backend agnostic.

The actual implementation here is an SHA1 hash of RPMDBI_NAME keys and
the corresponding package offsets, but this is an implementation detail
that can be changed anytime and callers must not rely on. The only thing
that matters is whether the string equals an earlier cookie value or not.
A cryptographic hash seems like an overkill, but then it saves us the
headaches of coming up with something that reflects order changes etc.

Closes: rpm-software-management#388
pmatilai added a commit to pmatilai/rpm that referenced this issue May 27, 2019
@pmatilai
Implement a database cookie API for determining whether rpmdb has cha…
2e26ca8 
…nged

Add rpmdbCookie() public function and matching python bindings.
The returned value is an opaque string which changes any time the rpmdb
is changed (eg packages added or removed, rebuild changes things etc).
A key point is that this is entirely database backend agnostic.

The actual implementation here is an SHA1 hash of RPMDBI_NAME keys and
the corresponding package offsets, but this is an implementation detail
that can be changed anytime and callers must not rely on. The only thing
that matters is whether the string equals an earlier cookie value or not.
A cryptographic hash seems like an overkill, but then it saves us the
headaches of coming up with something that reflects order changes etc.

Closes: rpm-software-management#388
ffesti pushed a commit that referenced this issue May 27, 2019
@pmatilai @ffesti
Implement a database cookie API for determining whether rpmdb has cha…
d1ebf65 
…nged

Add rpmdbCookie() public function and matching python bindings.
The returned value is an opaque string which changes any time the rpmdb
is changed (eg packages added or removed, rebuild changes things etc).
A key point is that this is entirely database backend agnostic.

The actual implementation here is an SHA1 hash of RPMDBI_NAME keys and
the corresponding package offsets, but this is an implementation detail
that can be changed anytime and callers must not rely on. The only thing
that matters is whether the string equals an earlier cookie value or not.
A cryptographic hash seems like an overkill, but then it saves us the
headaches of coming up with something that reflects order changes etc.

Closes: #388
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Implement a database cookie API for determining whether rpmdb has cha… pmatilai/rpm
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