forked from lix-project/lix
2af9fd20c6
the term was hard to discover, as its definition and explanation were in a very long document lacking an overview section. search did not help because it occurs so often. - clarify wording in the definition - add an overview of installable types - add "installable" to glossary - link to definition from occurrences of the term - be more precise about where store derivation outputs are processed - installable Nix expressions must evaluate to a derivation Co-authored-by: Adam Joseph <54836058+amjoseph-nixpkgs@users.noreply.github.com>
106 lines
3.1 KiB
Markdown
106 lines
3.1 KiB
Markdown
R""(
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# Examples
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* Show the [store derivation] that results from evaluating the Hello
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package:
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[store derivation]: ../../glossary.md#gloss-store-derivation
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```console
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# nix show-derivation nixpkgs#hello
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{
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"/nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv": {
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…
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}
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}
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```
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* Show the full derivation graph (if available) that produced your
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NixOS system:
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```console
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# nix show-derivation -r /run/current-system
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```
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* Print all files fetched using `fetchurl` by Firefox's dependency
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graph:
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```console
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# nix show-derivation -r nixpkgs#firefox \
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| jq -r '.[] | select(.outputs.out.hash and .env.urls) | .env.urls' \
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| uniq | sort
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```
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Note that `.outputs.out.hash` selects *fixed-output derivations*
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(derivations that produce output with a specified content hash),
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while `.env.urls` selects derivations with a `urls` attribute.
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# Description
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This command prints on standard output a JSON representation of the
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[store derivation]s to which [*installables*](./nix.md#installables) evaluate. Store derivations
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are used internally by Nix. They are store paths with extension `.drv`
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that represent the build-time dependency graph to which a Nix
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expression evaluates.
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By default, this command only shows top-level derivations, but with
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`--recursive`, it also shows their dependencies.
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The JSON output is a JSON object whose keys are the store paths of the
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derivations, and whose values are a JSON object with the following
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fields:
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* `outputs`: Information about the output paths of the
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derivation. This is a JSON object with one member per output, where
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the key is the output name and the value is a JSON object with these
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fields:
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* `path`: The output path.
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* `hashAlgo`: For fixed-output derivations, the hashing algorithm
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(e.g. `sha256`), optionally prefixed by `r:` if `hash` denotes a
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NAR hash rather than a flat file hash.
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* `hash`: For fixed-output derivations, the expected content hash in
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base-16.
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Example:
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```json
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"outputs": {
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"out": {
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"path": "/nix/store/2543j7c6jn75blc3drf4g5vhb1rhdq29-source",
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"hashAlgo": "r:sha256",
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"hash": "6fc80dcc62179dbc12fc0b5881275898f93444833d21b89dfe5f7fbcbb1d0d62"
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}
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}
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```
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* `inputSrcs`: A list of store paths on which this derivation depends.
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* `inputDrvs`: A JSON object specifying the derivations on which this
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derivation depends, and what outputs of those derivations. For
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example,
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```json
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"inputDrvs": {
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"/nix/store/6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"],
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"/nix/store/fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"]
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}
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```
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specifies that this derivation depends on the `dev` output of
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`curl`, and the `out` output of `unzip`.
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* `system`: The system type on which this derivation is to be built
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(e.g. `x86_64-linux`).
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* `builder`: The absolute path of the program to be executed to run
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the build. Typically this is the `bash` shell
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(e.g. `/nix/store/r3j288vpmczbl500w6zz89gyfa4nr0b1-bash-4.4-p23/bin/bash`).
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* `args`: The command-line arguments passed to the `builder`.
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* `env`: The environment passed to the `builder`.
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)""
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