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

Name

nix flake metadata - show flake metadata

Synopsis

nix flake metadata [option...] flake-url

Examples

  • Show what nixpkgs resolves to:

    # nix flake metadata nixpkgs
    Resolved URL:  github:edolstra/dwarffs
    Locked URL:    github:edolstra/dwarffs/f691e2c991e75edb22836f1dbe632c40324215c5
    Description:   A filesystem that fetches DWARF debug info from the Internet on demand
    Path:          /nix/store/769s05vjydmc2lcf6b02az28wsa9ixh1-source
    Revision:      f691e2c991e75edb22836f1dbe632c40324215c5
    Last modified: 2021-01-21 15:41:26
    Inputs:
    ├───nix: github:NixOS/nix/6254b1f5d298ff73127d7b0f0da48f142bdc753c
    │   ├───lowdown-src: github:kristapsdz/lowdown/1705b4a26fbf065d9574dce47a94e8c7c79e052f
    │   └───nixpkgs: github:NixOS/nixpkgs/ad0d20345219790533ebe06571f82ed6b034db31
    └───nixpkgs follows input 'nix/nixpkgs'
    
  • Show information about dwarffs in JSON format:

    # nix flake metadata dwarffs --json | jq .
    {
      "description": "A filesystem that fetches DWARF debug info from the Internet on demand",
      "lastModified": 1597153508,
      "locked": {
        "lastModified": 1597153508,
        "narHash": "sha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0=",
        "owner": "edolstra",
        "repo": "dwarffs",
        "rev": "d181d714fd36eb06f4992a1997cd5601e26db8f5",
        "type": "github"
      },
      "locks": { ... },
      "original": {
        "id": "dwarffs",
        "type": "indirect"
      },
      "originalUrl": "flake:dwarffs",
      "path": "/nix/store/hang3792qwdmm2n0d9nsrs5n6bsws6kv-source",
      "resolved": {
        "owner": "edolstra",
        "repo": "dwarffs",
        "type": "github"
      },
      "resolvedUrl": "github:edolstra/dwarffs",
      "revision": "d181d714fd36eb06f4992a1997cd5601e26db8f5",
      "url": "github:edolstra/dwarffs/d181d714fd36eb06f4992a1997cd5601e26db8f5"
    }
    

Description

This command shows information about the flake specified by the flake reference flake-url. It resolves the flake reference using the flake registry, fetches it, and prints some meta data. This includes:

  • Resolved URL: If flake-url is a flake identifier, then this is the flake reference that specifies its actual location, looked up in the flake registry.

  • Locked URL: A flake reference that contains a commit or content hash and thus uniquely identifies a specific flake version.

  • Description: A one-line description of the flake, taken from the description field in flake.nix.

  • Path: The store path containing the source code of the flake.

  • Revision: The Git or Mercurial commit hash of the locked flake.

  • Revisions: The number of ancestors of the Git or Mercurial commit of the locked flake. Note that this is not available for github flakes.

  • Last modified: For Git or Mercurial flakes, this is the commit time of the commit of the locked flake; for tarball flakes, it's the most recent timestamp of any file inside the tarball.

  • Inputs: The flake inputs with their corresponding lock file entries.

With --json, the output is a JSON object with the following fields:

  • original and originalUrl: The flake reference specified by the user (flake-url) in attribute set and URL representation.

  • resolved and resolvedUrl: The resolved flake reference (see above) in attribute set and URL representation.

  • locked and lockedUrl: The locked flake reference (see above) in attribute set and URL representation.

  • description: See Description above.

  • path: See Path above.

  • revision: See Revision above.

  • revCount: See Revisions above.

  • lastModified: See Last modified above.

  • locks: The contents of flake.lock.

Options

  • --json

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

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 Nix store to use for evaluations.

  • --impure

    Allow access to mutable paths and repositories.

  • --include / -I path

    Add path to the list of locations used to look up <...> file names.

  • --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.

  • --override-input input-path flake-url

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

  • --recreate-lock-file

    Recreate the flake's lock file from scratch.

  • --update-input input-path

    Update a specific flake input (ignoring its previous entry in the lock file).

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 Nix configuration setting name to value (overriding nix.conf).

  • --refresh

    Consider all previously downloaded files out-of-date.

  • --version

    Show version information.

Options to override configuration settings:

  • --accept-flake-config

    Enable the accept-flake-config setting.

  • --access-tokens value

    Set the access-tokens setting.

  • --allow-dirty

    Enable the allow-dirty setting.

  • --allow-import-from-derivation

    Enable the allow-import-from-derivation setting.

  • --allow-new-privileges

    Enable the allow-new-privileges setting.

  • --allow-symlinked-store

    Enable the allow-symlinked-store setting.

  • --allow-unsafe-native-code-during-evaluation

    Enable the allow-unsafe-native-code-during-evaluation setting.

  • --allowed-impure-host-deps value

    Set the allowed-impure-host-deps setting.

  • --allowed-uris value

    Set the allowed-uris setting.

  • --allowed-users value

    Set the allowed-users setting.

  • --auto-optimise-store

    Enable the auto-optimise-store setting.

  • --bash-prompt value

    Set the bash-prompt setting.

  • --bash-prompt-prefix value

    Set the bash-prompt-prefix setting.

  • --bash-prompt-suffix value

    Set the bash-prompt-suffix setting.

  • --build-hook value

    Set the build-hook setting.

  • --build-poll-interval value

    Set the build-poll-interval setting.

  • --build-users-group value

    Set the build-users-group setting.

  • --builders value

    Set the builders setting.

  • --builders-use-substitutes

    Enable the builders-use-substitutes setting.

  • --commit-lockfile-summary value

    Set the commit-lockfile-summary setting.

  • --compress-build-log

    Enable the compress-build-log setting.

  • --connect-timeout value

    Set the connect-timeout setting.

  • --cores value

    Set the cores setting.

  • --diff-hook value

    Set the diff-hook setting.

  • --download-attempts value

    Set the download-attempts setting.

  • --download-speed value

    Set the download-speed setting.

  • --enforce-determinism

    Enable the enforce-determinism setting.

  • --eval-cache

    Enable the eval-cache setting.

  • --experimental-features value

    Set the experimental-features setting.

  • --extra-access-tokens value

    Append to the access-tokens setting.

  • --extra-allowed-impure-host-deps value

    Append to the allowed-impure-host-deps setting.

  • --extra-allowed-uris value

    Append to the allowed-uris setting.

  • --extra-allowed-users value

    Append to the allowed-users setting.

  • --extra-experimental-features value

    Append to the experimental-features setting.

  • --extra-extra-platforms value

    Append to the extra-platforms setting.

  • --extra-hashed-mirrors value

    Append to the hashed-mirrors setting.

  • --extra-ignored-acls value

    Append to the ignored-acls setting.

  • --extra-nix-path value

    Append to the nix-path setting.

  • --extra-platforms value

    Set the extra-platforms setting.

  • --extra-plugin-files value

    Append to the plugin-files setting.

  • --extra-sandbox-paths value

    Append to the sandbox-paths setting.

  • --extra-secret-key-files value

    Append to the secret-key-files setting.

  • --extra-substituters value

    Append to the substituters setting.

  • --extra-system-features value

    Append to the system-features setting.

  • --extra-trusted-public-keys value

    Append to the trusted-public-keys setting.

  • --extra-trusted-substituters value

    Append to the trusted-substituters setting.

  • --extra-trusted-users value

    Append to the trusted-users setting.

  • --fallback

    Enable the fallback setting.

  • --filter-syscalls

    Enable the filter-syscalls setting.

  • --flake-registry value

    Set the flake-registry setting.

  • --fsync-metadata

    Enable the fsync-metadata setting.

  • --gc-reserved-space value

    Set the gc-reserved-space setting.

  • --hashed-mirrors value

    Set the hashed-mirrors setting.

  • --http-connections value

    Set the http-connections setting.

  • --http2

    Enable the http2 setting.

  • --ignore-try

    Enable the ignore-try setting.

  • --ignored-acls value

    Set the ignored-acls setting.

  • --impersonate-linux-26

    Enable the impersonate-linux-26 setting.

  • --keep-build-log

    Enable the keep-build-log setting.

  • --keep-derivations

    Enable the keep-derivations setting.

  • --keep-env-derivations

    Enable the keep-env-derivations setting.

  • --keep-failed

    Enable the keep-failed setting.

  • --keep-going

    Enable the keep-going setting.

  • --keep-outputs

    Enable the keep-outputs setting.

  • --log-lines value

    Set the log-lines setting.

  • --max-build-log-size value

    Set the max-build-log-size setting.

  • --max-free value

    Set the max-free setting.

  • --max-jobs value

    Set the max-jobs setting.

  • --max-silent-time value

    Set the max-silent-time setting.

  • --min-free value

    Set the min-free setting.

  • --min-free-check-interval value

    Set the min-free-check-interval setting.

  • --nar-buffer-size value

    Set the nar-buffer-size setting.

  • --narinfo-cache-negative-ttl value

    Set the narinfo-cache-negative-ttl setting.

  • --narinfo-cache-positive-ttl value

    Set the narinfo-cache-positive-ttl setting.

  • --netrc-file value

    Set the netrc-file setting.

  • --nix-path value

    Set the nix-path setting.

  • --no-accept-flake-config

    Disable the accept-flake-config setting.

  • --no-allow-dirty

    Disable the allow-dirty setting.

  • --no-allow-import-from-derivation

    Disable the allow-import-from-derivation setting.

  • --no-allow-new-privileges

    Disable the allow-new-privileges setting.

  • --no-allow-symlinked-store

    Disable the allow-symlinked-store setting.

  • --no-allow-unsafe-native-code-during-evaluation

    Disable the allow-unsafe-native-code-during-evaluation setting.

  • --no-auto-optimise-store

    Disable the auto-optimise-store setting.

  • --no-builders-use-substitutes

    Disable the builders-use-substitutes setting.

  • --no-compress-build-log

    Disable the compress-build-log setting.

  • --no-enforce-determinism

    Disable the enforce-determinism setting.

  • --no-eval-cache

    Disable the eval-cache setting.

  • --no-fallback

    Disable the fallback setting.

  • --no-filter-syscalls

    Disable the filter-syscalls setting.

  • --no-fsync-metadata

    Disable the fsync-metadata setting.

  • --no-http2

    Disable the http2 setting.

  • --no-ignore-try

    Disable the ignore-try setting.

  • --no-impersonate-linux-26

    Disable the impersonate-linux-26 setting.

  • --no-keep-build-log

    Disable the keep-build-log setting.

  • --no-keep-derivations

    Disable the keep-derivations setting.

  • --no-keep-env-derivations

    Disable the keep-env-derivations setting.

  • --no-keep-failed

    Disable the keep-failed setting.

  • --no-keep-going

    Disable the keep-going setting.

  • --no-keep-outputs

    Disable the keep-outputs setting.

  • --no-preallocate-contents

    Disable the preallocate-contents setting.

  • --no-print-missing

    Disable the print-missing setting.

  • --no-pure-eval

    Disable the pure-eval setting.

  • --no-require-sigs

    Disable the require-sigs setting.

  • --no-restrict-eval

    Disable the restrict-eval setting.

  • --no-run-diff-hook

    Disable the run-diff-hook setting.

  • --no-sandbox

    Disable sandboxing.

  • --no-sandbox-fallback

    Disable the sandbox-fallback setting.

  • --no-show-trace

    Disable the show-trace setting.

  • --no-substitute

    Disable the substitute setting.

  • --no-sync-before-registering

    Disable the sync-before-registering setting.

  • --no-trace-function-calls

    Disable the trace-function-calls setting.

  • --no-trace-verbose

    Disable the trace-verbose setting.

  • --no-use-case-hack

    Disable the use-case-hack setting.

  • --no-use-registries

    Disable the use-registries setting.

  • --no-use-sqlite-wal

    Disable the use-sqlite-wal setting.

  • --no-warn-dirty

    Disable the warn-dirty setting.

  • --plugin-files value

    Set the plugin-files setting.

  • --post-build-hook value

    Set the post-build-hook setting.

  • --pre-build-hook value

    Set the pre-build-hook setting.

  • --preallocate-contents

    Enable the preallocate-contents setting.

  • --print-missing

    Enable the print-missing setting.

  • --pure-eval

    Enable the pure-eval setting.

  • --relaxed-sandbox

    Enable sandboxing, but allow builds to disable it.

  • --repeat value

    Set the repeat setting.

  • --require-sigs

    Enable the require-sigs setting.

  • --restrict-eval

    Enable the restrict-eval setting.

  • --run-diff-hook

    Enable the run-diff-hook setting.

  • --sandbox

    Enable sandboxing.

  • --sandbox-build-dir value

    Set the sandbox-build-dir setting.

  • --sandbox-dev-shm-size value

    Set the sandbox-dev-shm-size setting.

  • --sandbox-fallback

    Enable the sandbox-fallback setting.

  • --sandbox-paths value

    Set the sandbox-paths setting.

  • --secret-key-files value

    Set the secret-key-files setting.

  • --show-trace

    Enable the show-trace setting.

  • --stalled-download-timeout value

    Set the stalled-download-timeout setting.

  • --store value

    Set the store setting.

  • --substitute

    Enable the substitute setting.

  • --substituters value

    Set the substituters setting.

  • --sync-before-registering

    Enable the sync-before-registering setting.

  • --system value

    Set the system setting.

  • --system-features value

    Set the system-features setting.

  • --tarball-ttl value

    Set the tarball-ttl setting.

  • --timeout value

    Set the timeout setting.

  • --trace-function-calls

    Enable the trace-function-calls setting.

  • --trace-verbose

    Enable the trace-verbose setting.

  • --trusted-public-keys value

    Set the trusted-public-keys setting.

  • --trusted-substituters value

    Set the trusted-substituters setting.

  • --trusted-users value

    Set the trusted-users setting.

  • --use-case-hack

    Enable the use-case-hack setting.

  • --use-registries

    Enable the use-registries setting.

  • --use-sqlite-wal

    Enable the use-sqlite-wal setting.

  • --user-agent-suffix value

    Set the user-agent-suffix setting.

  • --warn-dirty

    Enable the warn-dirty setting.