diff options
Diffstat (limited to 'src/nix/show-derivation.md')
-rw-r--r-- | src/nix/show-derivation.md | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/src/nix/show-derivation.md b/src/nix/show-derivation.md new file mode 100644 index 000000000..aa863899c --- /dev/null +++ b/src/nix/show-derivation.md @@ -0,0 +1,103 @@ +R""( + +# Examples + +* Show the store derivation that results from evaluating the Hello + package: + + ```console + # nix show-derivation nixpkgs#hello + { + "/nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv": { + … + } + } + ``` + +* Show the full derivation graph (if available) that produced your + NixOS system: + + ```console + # nix show-derivation -r /run/current-system + ``` + +* Print all files fetched using `fetchurl` by Firefox's dependency + graph: + + ```console + # nix show-derivation -r nixpkgs#firefox \ + | jq -r '.[] | select(.outputs.out.hash and .env.urls) | .env.urls' \ + | uniq | sort + ``` + + Note that `.outputs.out.hash` selects *fixed-output derivations* + (derivations that produce output with a specified content hash), + while `.env.urls` selects derivations with a `urls` attribute. + +# Description + +This command prints on standard output a JSON representation of the +store derivations to which *installables* evaluate. Store derivations +are used internally by Nix. They are store paths with extension `.drv` +that represent the build-time dependency graph to which a Nix +expression evaluates. + +By default, this command only shows top-level derivations, but with +`--recursive`, it also shows their dependencies. + +The JSON output is a JSON object whose keys are the store paths of the +derivations, and whose values are a JSON object with the following +fields: + +* `outputs`: Information about the output paths of the + derivation. This is a JSON object with one member per output, where + the key is the output name and the value is a JSON object with these + fields: + + * `path`: The output path. + * `hashAlgo`: For fixed-output derivations, the hashing algorithm + (e.g. `sha256`), optionally prefixed by `r:` if `hash` denotes a + NAR hash rather than a flat file hash. + * `hash`: For fixed-output derivations, the expected content hash in + base-16. + + Example: + + ```json + "outputs": { + "out": { + "path": "/nix/store/2543j7c6jn75blc3drf4g5vhb1rhdq29-source", + "hashAlgo": "r:sha256", + "hash": "6fc80dcc62179dbc12fc0b5881275898f93444833d21b89dfe5f7fbcbb1d0d62" + } + } + ``` + +* `inputSrcs`: A list of store paths on which this derivation depends. + +* `inputDrvs`: A JSON object specifying the derivations on which this + derivation depends, and what outputs of those derivations. For + example, + + ```json + "inputDrvs": { + "/nix/store/6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"], + "/nix/store/fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"] + } + ``` + + specifies that this derivation depends on the `dev` output of + `curl`, and the `out` output of `unzip`. + +* `system`: The system type on which this derivation is to be built + (e.g. `x86_64-linux`). + +* `builder`: The absolute path of the program to be executed to run + the build. Typically this is the `bash` shell + (e.g. `/nix/store/r3j288vpmczbl500w6zz89gyfa4nr0b1-bash-4.4-p23/bin/bash`). + +* `args`: The command-line arguments passed to the `builder`. + +* `env`: The environment passed to the `builder`. + +)"" |