Before this, there could be crash during a call to finalize a ref that
occured after the snapshot was committed but before committing the
metadata that indicates the immutable ref no longer had an
equalMutable. This resulted in a situation where any future calls to
finalize that ref would fail.
Now, if that situation happens, the cache will notice when it's
initially loaded that the ref has an equalMutable that's missing its
snapshot and that its own snapshot exists. It will then just use the
correctly committed snapshot and clear the equalMutable field.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
This allows you to create refs that are single layers representing the
diff between any two arbitrary refs. The primary use case for this is
to allows users to extract the changes created by ops like Exec and
rebase them elsewhere through MergeOp. However, there is no restriction
on the inputs to DiffOp and the resulting ref's layer is simply the
layer created by running the differ on the two inputs refs
(specifically, the same differ used during exports).
A Diff ref can be mounted by itself, in which case it is defined as the
result of applying the diff to Scratch. Most use cases though will use
Diff refs as the input to a MergeOp, in which case the diff is just
applied on top of the lower merge inputs, as was the case before.
In cases like Diff(A, A->B->C) (i.e. cases where the diff is between two
refs where the lower is an ancestor of upper), the diff will be defined
as the layers separating the two refs. In other cases, the diff is just
a single layer, not re-used from the inputs, representing the diff
between the two refs (which can be defined as the layer "Diff(A,B)" that
satisfies "Merge(A, Diff(A,B)) == B").
Note that there is technically a meaningful difference between the
"unmerge" behavior of extracting the layers separating diffs and the
"simple diff" of just running the differ on the two refs. Namely, in the
case where there are "intermediate deletes" (i.e. deletes that only
exist in layers between A and B but not between A and B by themselves),
then the simple diff and unmerge can create different results when
plugged into a MergeOp. This is due to the fact that intermediate
deletes will apply to the merge when using the unmerge behavior, but not
when using the simple diff. This is on top of the fact that the simple
diff inherently has a "flattening" behavior where multiple layers are
squashed into a single one.
So, in the case where lower is an ancestor of upper, we choose to follow
the unmerge behavior, but it's possible users may prefer the simple diff
behavior. As of right now, they won't be able to do so, but if needed we
can add the ability to choose which behavior is followed in the future.
This could be done through a flag provided to DiffOp or possibly by
adapting llb.Copy to support this type of behavior with the same
efficiency as DiffOp.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
Before this, if you try to get a ref with an equal blobchain in
GetByBlob but hit a missing provider, the error was just returned. While
we never expect this situation to happen (you shouldn't be able to hit
this line if you didn't already have providers for each blob in the
chain), it technically shouldn't fail the build as you can just continue
on without re-using the ref with equal blobchainID.
Now, we log this at error level but allow the build to continue.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
This consists of just the base MergeOp with support for merging LLB
results that include deletions using hardlinks as the efficient path
and copies as fallback.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
This is mostly just preparation for merge-op. The existing
Extract method is updated to be usable for unlazying any type of refs
rather than just lazy blobs. The way views are created is simplified and
centralized in one location.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
It turns out that while Buildkit code did not need this method to
be public, moby code does still use it, so we have to re-add it
after its removal in #2216 (commit b85ef15).
This commit is not a revert because some of the changes are
still desireable, namely the removal of the "commit" parameter
which didn't serve any purpose.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
There are a few goals with this refactor:
1. Remove external access to fields that no longer make sense and/or
won't make sense soon due to other potential changes. For example,
there can now be multiple blobs associated with a ref (for different
compression types), so the fact that you could access the "Blob"
field from the Info method on Ref incorrectly implied there was just
a single blob for the ref. This is on top of the fact that there is
no need for external access to blob digests.
2. Centralize use of cache metadata inside the cache package.
Previously, many parts of the code outside the cache package could
obtain the bolt storage item for any ref and read/write it directly.
This made it hard to understand what fields are used and when. Now,
the Metadata method has been removed from the Ref interface and
replaced with getters+setters for metadata fields we want to expose
outside the package, which makes it much easier to track and
understand. Similar changes have been made to the metadata search
interface.
3. Use a consistent getter+setter interface for metadata, replacing
the mix of interfaces like Metadata(), Size(), Info() and other
inconsistencies.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
GetByBlob checks to see if there are any other blobs with the same
(uncompressed) ChainID and, if so, reuses their unpacked snapshot if it
exists.
The problem is if this code finds a match, it was trying to get the
matching record, but couldn't do so when the match is lazy because the
caller doesn't necessarily have descriptor handlers setup for it.
This commit changes the behavior to just ignore any match with the same
ChainID that's also lazy as they just aren't usable for the
snapshot-reuse optimization.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
Finalize was only used outside the cache package in one place, which
called it with the commit arg set to false. The code path followed
when commit==false turned out to essentially be a no-op because
it set "retain cache" to true if it was already set to true.
It was thus safe to remove the only external call to it and remove it
from the interface. This should be helpful for future efforts to
simplify the equal{Mutable,Immutable} fields in cacheRecord, which exist
due to the "lazy commit" feature that Finalize is tied into.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
I noticed this when building a Dockerfile that failed because a file didn't
exist, so went through error messages that looked like they had a duplicate
"not found" in the output;
[+] Building 0.9s (6/9)
=> [internal] load build definition from Dockerfile 0.2s
=> => transferring dockerfile: 306B 0.0s
=> [internal] load .dockerignore 0.1s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/alpine:latest 0.0s
=> CACHED [1/5] FROM docker.io/library/alpine 0.0s
=> [internal] load build context 0.6s
=> => transferring context: 701B 0.5s
=> ERROR [2/5] ADD no-such-file.txt / 0.0s
------
> [2/5] ADD no-such-file.txt /:
------
failed to compute cache key: "/no-such-file.txt" not found: not found
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
[5/5] RUN --mount=target=/go/src/github.com/moby/buildkit gometalinter ...
0.435 util/rootless/specconv/specconv_linux.go:1:⚠️ file is not goimported (goimports)
1.320 cache/manager.go:1:⚠️ file is not goimported (goimports)
1.335 cache/manager_test.go:1:⚠️ file is not goimported (goimports)
1.337 cache/migrate_v2.go:1:⚠️ file is not goimported (goimports)
1.342 cache/refs.go:1:⚠️ file is not goimported (goimports)
1.454 cache/remotecache/registry/registry.go:1:⚠️ file is not goimported (goimports)
2.285 cmd/buildctl/build.go:1:⚠️ file is not goimported (goimports)
3.082 executor/oci/user.go:1:⚠️ file is not goimported (goimports)
4.333 session/content/content_test.go:1:⚠️ file is not goimported (goimports)
4.614 snapshot/containerd/content.go:1:⚠️ file is not goimported (goimports)
4.721 solver/errdefs/vertex.go:1:⚠️ file is not goimported (goimports)
6.066 util/network/cniprovider/cni.go:1:⚠️ file is not goimported (goimports)
ERROR: executor failed running [/bin/sh -c gometalinter --config=gometalinter.json ./...]: buildkit-runc did not terminate successfully
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Erik Sipsma
Koichi Shiraishi
Tõnis Tiigi
ktock
Sebastiaan van Stijn
Tibor Vass
HowJMay
Tibor Vass