e05e8bdd03
These are intended to help digest the protocol definitions for tvix- store, and how they tie into the whole concept. Co-Authored-By: Vincent Ambo <mail@tazj.in> Change-Id: Ic1ba3ba41ef599209453f15d0ac2e07a6144bcca Reviewed-on: https://cl.tvl.fyi/c/depot/+/7439 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su>
50 lines
1.9 KiB
Markdown
50 lines
1.9 KiB
Markdown
# //tvix/store/docs/castore.md
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This provides some more notes on the fields used in castore.proto.
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It's meant to supplement `//tvix/store/docs/api.md`.
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## Directory message
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`Directory` messages use the blake3 hash of their canonical protobuf
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serialization as its identifier.
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A `Directory` message contains three lists, `directories`, `files` and
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`symlinks`, holding `DirectoryNode`, `FileNode` and `SymlinkNode` messages
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respectively. They describe all the direct child elements that are contained in
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a directory.
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All three message types have a `name` field, specifying the (base)name of the
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element (which MUST not contain slashes or null bytes, and MUST not be '.' or '..').
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For reproducibility reasons, the lists MUST be sorted by that name and also
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MUST be unique across all three lists.
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In addition to the `name` field, the various *Node messages have the following
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fields:
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## DirectoryNode
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A `DirectoryNode` message represents a child directory.
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It has a `digest` field, which points to the identifier of another `Directory`
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message, making a `Directory` a merkle tree (or strictly speaking, a graph, as
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two elements pointing to a child directory with the same contents would point
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to the same `Directory` message.
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There's also a `size` field, containing the (total) number of all child
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elements in the referenced `Directory`, which helps for inode calculation.
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## FileNode
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A `FileNode` message represents a child (regular) file.
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Its `digest` field contains the blake3 hash of the file contents. It can be
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looked up in the `BlobService`.
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The `size` field contains the size of the blob the `digest` field refers to.
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The `executable` field specifies whether the file should be marked as
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executable or not.
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## SymlinkNode
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A `SymlinkNode` message represents a child symlink.
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In addition to the `name` field, the only additional field is the `target`,
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which is a string containing the target of the symlink.
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