3281fb9132
This documents the input and output format, and also removes some references to Terraform and evaluating NixOS system configurations. It can be used to evaluate anything. Change-Id: I8492cc3e386f89b299469c78e586644ee82a708f Reviewed-on: https://cl.tvl.fyi/c/depot/+/11213 Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
34 lines
1.2 KiB
Bash
Executable file
34 lines
1.2 KiB
Bash
Executable file
#!/usr/bin/env bash
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# SPDX-FileCopyrightText: 2023 The TVL Authors
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#
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# SPDX-License-Identifier: MIT
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set -ueo pipefail
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# Evaluates a Nix expression.
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#
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# Receives input parameters as JSON from stdin.
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# It expects a dict with the following keys:
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#
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# - `attrpath`: the attribute.path pointing to the expression to instantiate.
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# Required.
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# - `entrypoint`: the path to the Nix file to invoke.
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# Optional. If omitted, will shell out to git to determine the repo root,
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# and Nix will use `default.nix` in there.
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# - `argstr`: A map containing string keys and values
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# which are passed to Nix as `--argstr $key $value`
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# command line args. Optional.
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#
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# jq's @sh format takes care of escaping.
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eval "$(jq -r '@sh "attrpath=\(.attrpath) && entrypoint=\(.entrypoint) && argstr=\((.argstr // {}) | to_entries | map ("--argstr", .key, .value) | join(" "))"')"
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# Evaluate the expression.
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[[ -z "$entrypoint" ]] && entrypoint=$(git rev-parse --show-toplevel)
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# shellcheck disable=SC2086,SC2154
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drv=$(nix-instantiate -A "${attrpath}" "${entrypoint}" ${argstr})
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# Return a JSON back to stdout.
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# It contains the following keys:
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#
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# - `drv`: the store path of the Derivation that has been instantiated.
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jq -n --arg drv "$drv" '{"drv":$drv}'
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