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authorJohn Ericson <John.Ericson@Obsidian.Systems>2021-02-25 20:35:11 +0000
committerJohn Ericson <John.Ericson@Obsidian.Systems>2021-02-25 21:51:05 +0000
commitca0994819d68aee26a2906c37a47ae609ac46c4c (patch)
treec96805c008c22926b1eaadc340a99323d53be532 /src/nix/make-content-addressable.md
parent10e81bf871551901ff0383bdede0f79325e93867 (diff)
parentc189031e8be0530d73a817571ad7f81ad5eedce6 (diff)
Merge remote-tracking branch 'upstream/master' into path-info
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+R""(
+
+# Examples
+
+* Create a content-addressed representation of the closure of GNU Hello:
+
+ ```console
+ # nix store make-content-addressable -r nixpkgs#hello
+ …
+ rewrote '/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10' to '/nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10'
+ ```
+
+ Since the resulting paths are content-addressed, they are always
+ trusted and don't need signatures to copied to another store:
+
+ ```console
+ # nix copy --to /tmp/nix --trusted-public-keys '' /nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10
+ ```
+
+ By contrast, the original closure is input-addressed, so it does
+ need signatures to be trusted:
+
+ ```console
+ # nix copy --to /tmp/nix --trusted-public-keys '' nixpkgs#hello
+ cannot add path '/nix/store/zy9wbxwcygrwnh8n2w9qbbcr6zk87m26-libunistring-0.9.10' because it lacks a valid signature
+ ```
+
+* Create a content-addressed representation of the current NixOS
+ system closure:
+
+ ```console
+ # nix store make-content-addressable -r /run/current-system
+ ```
+
+# Description
+
+This command converts the closure of the store paths specified by
+*installables* to content-addressed form. Nix store paths are usually
+*input-addressed*, meaning that the hash part of the store path is
+computed from the contents of the derivation (i.e., the build-time
+dependency graph). Input-addressed paths need to be signed by a
+trusted key if you want to import them into a store, because we need
+to trust that the contents of the path were actually built by the
+derivation.
+
+By contrast, in a *content-addressed* path, the hash part is computed
+from the contents of the path. This allows the contents of the path to
+be verified without any additional information such as
+signatures. This means that a command like
+
+```console
+# nix store build /nix/store/5skmmcb9svys5lj3kbsrjg7vf2irid63-hello-2.10 \
+ --substituters https://my-cache.example.org
+```
+
+will succeed even if the binary cache `https://my-cache.example.org`
+doesn't present any signatures.
+
+)""