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nix store make-content-addressed

Rewrite a path or closure to content-addressed form.

Warning

This program is experimental and its interface is subject to change.

Synopsis

nix store make-content-addressed [option...] installables...

Examples

  • Create a content-addressed representation of the closure of GNU Hello:
## nix store make-content-addressed 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:

## 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:

## nix copy --to /tmp/nix --trusted-public-keys '' nixpkgs#hello
cannot add path '/nix/store/zy9wbxwcygrwnh8n2w9qbbcr6zk87m26-libunistring-0.9.10' because it lacks a signature by a trusted key
  • Create a content-addressed representation of the current NixOS system closure:
## nix store make-content-addressed /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

## 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.

Options

  • --from store-uri URL of the source Nix store.

  • --json Produce output in JSON format, suitable for consumption by another program.

  • --stdin Read installables from the standard input. No default installable applied.

  • --to store-uri URL of the destination Nix store.

Common evaluation options:

  • --arg name expr Pass the value expr as the argument name to Nix functions.

  • --argstr name string Pass the string string as the argument name to Nix functions.

  • --debugger Start an interactive environment if evaluation fails.

  • --eval-store store-url The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.

  • --impure Allow access to mutable paths and repositories.

  • --include / -I path Add path to the Nix search path. The Nix search path is initialized from the colon-separated NIX_PATH environment variable, and is used to look up the location of Nix expressions using paths enclosed in angle brackets (i.e., <nixpkgs>).

For instance, passing

-I /home/eelco/Dev
-I /etc/nixos

will cause Lix to look for paths relative to /home/eelco/Dev and /etc/nixos, in that order. This is equivalent to setting the NIX_PATH environment variable to

/home/eelco/Dev:/etc/nixos

It is also possible to match paths against a prefix. For example, passing

-I nixpkgs=/home/eelco/Dev/nixpkgs-branch
-I /etc/nixos

will cause Lix to search for <nixpkgs/path> in /home/eelco/Dev/nixpkgs-branch/path and /etc/nixos/nixpkgs/path.

If a path in the Nix search path starts with http:// or https://, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing

-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz

tells Lix to download and use the current contents of the master branch in the nixpkgs repository.

The URLs of the tarballs from the official nixos.org channels (see the manual page for nix-channel) can be abbreviated as channel:<channel-name>. For instance, the following two flags are equivalent:

-I nixpkgs=channel:nixos-21.05
-I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xz

You can also fetch source trees using flake URLs and add them to the search path. For instance,

-I nixpkgs=flake:nixpkgs

specifies that the prefix nixpkgs shall refer to the source tree downloaded from the nixpkgs entry in the flake registry. Similarly,

-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05

makes <nixpkgs> refer to a particular branch of the NixOS/nixpkgs repository on GitHub.

  • --override-flake original-ref resolved-ref Override the flake registries, redirecting original-ref to resolved-ref.

Common flake-related options:

  • --commit-lock-file Commit changes to the flake's lock file.

  • --inputs-from flake-url Use the inputs of the specified flake as registry entries.

  • --no-registries Don't allow lookups in the flake registries. This option is deprecated; use --no-use-registries.

  • --no-update-lock-file Do not allow any updates to the flake's lock file.

  • --no-write-lock-file Do not write the flake's newly generated lock file.

  • --output-lock-file flake-lock-path Write the given lock file instead of flake.lock within the top-level flake.

  • --override-input input-path flake-url Override a specific flake input (e.g. dwarffs/nixpkgs). This implies --no-write-lock-file.

  • --reference-lock-file flake-lock-path Read the given lock file instead of flake.lock within the top-level flake.

Logging-related options:

  • --debug Set the logging verbosity level to 'debug'.

  • --log-format format Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

  • --print-build-logs / -L Print full build logs on standard error.

  • --quiet Decrease the logging verbosity level.

  • --verbose / -v Increase the logging verbosity level.

Miscellaneous global options:

  • --help Show usage information.

  • --offline Disable substituters and consider all previously downloaded files up-to-date.

  • --option name value Set the Lix configuration setting name to value (overriding nix.conf).

  • --refresh Consider all previously downloaded files out-of-date.

  • --repair During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.

  • --version Show version information.

Options that change the interpretation of installables:

  • --all Apply the operation to every store path.

  • --derivation Operate on the store derivation rather than its outputs.

  • --expr / -E expr Interpret installables as attribute paths relative to the Nix expression expr.

  • --file / -f file Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input. Implies --impure.

  • --recursive / -r Apply operation to closure of the specified paths.

Note

See man nix.conf for overriding configuration settings with command line flags.