Deployment and lifecycle management for Nix
feat: add Nix.Cache.Niks3 binary cache backend
Add niks3 cache backend that delegates to the niks3 CLI tool for
uploading store paths to S3-compatible binary caches. Config comes
entirely from the environment (NIKS3_SERVER_URL, auth token files).
Register niks3:// URL scheme in SowerCli.Cache.parse_url.
sow-88
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
+115
+110
apps/nix/lib/nix/cache/niks3.ex
+110
apps/nix/lib/nix/cache/niks3.ex
···
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defmodule Nix.Cache.Niks3 do
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@moduledoc """
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Binary cache backend using niks3.
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niks3 uploads Nix store paths to an S3-compatible binary cache.
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Server URL and auth token are read from the environment
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(`NIKS3_SERVER_URL`, `NIKS3_AUTH_TOKEN_FILE` or
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`$XDG_CONFIG_HOME/niks3/auth-token`).
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## Configuration
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%{}
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No configuration is required — all settings come from the environment.
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## Example
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{:ok, result} = Nix.Cache.Niks3.upload([
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"/nix/store/abc123-foo",
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"/nix/store/xyz789-bar"
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], %{})
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"""
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use Nix.Cache
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require Logger
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@impl Nix.Cache
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def name(), do: "niks3"
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@impl Nix.Cache
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def validate_config(%{}), do: :ok
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@impl Nix.Cache
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def upload(path, config) when not is_list(path), do: upload([path], config)
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def upload(paths, _config) when is_list(paths) do
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if length(paths) == 0 do
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{:ok, %{uploaded: [], failed: []}}
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else
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paths = ensure_store_paths(paths)
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niks3_cmd = System.find_executable("niks3")
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if is_nil(niks3_cmd) do
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{:error, "niks3 command not found in PATH"}
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else
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do_upload(niks3_cmd, paths)
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end
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end
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end
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defp do_upload(niks3_cmd, paths) do
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args = ["push"] ++ paths
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Logger.debug(
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msg: "Uploading to cache",
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backend: "niks3",
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path_count: to_string(length(paths))
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)
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case System.cmd(niks3_cmd, args, stderr_to_stdout: true) do
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{_output, 0} ->
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Logger.info(
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msg: "Upload succeeded",
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backend: "niks3",
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path_count: to_string(length(paths))
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)
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{:ok, %{uploaded: paths, failed: []}}
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{output, exit_code} ->
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Logger.error(
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msg: "Upload failed",
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backend: "niks3",
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exit_code: to_string(exit_code),
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output: String.slice(output, 0, 500)
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)
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error_reason = parse_error(output, exit_code)
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{:error, error_reason}
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end
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end
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defp parse_error(output, exit_code) do
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cond do
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String.contains?(output, "401") or
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String.contains?(output, "unauthorized") or
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String.contains?(output, "Unauthorized") ->
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"authentication failed - check auth token"
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String.contains?(output, "connection refused") or
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String.contains?(output, "Connection refused") ->
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"connection refused - check server URL"
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String.contains?(output, "no such host") or
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String.contains?(output, "No such host") ->
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"server not found - check server URL"
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true ->
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first_line =
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output
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|> String.split("\n", parts: 2)
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|> List.first()
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|> String.slice(0, 200)
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{exit_code, first_line}
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end
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end
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end
+4
apps/sower_cli/lib/sower_cli/cache.ex
+4
apps/sower_cli/lib/sower_cli/cache.ex
···
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iex> SowerCli.Cache.parse_url("ssh://user@host")
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{:ok, {Nix.Cache.NixCopy, %{destination: "ssh://user@host"}}}
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"""
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def parse_url("niks3://" <> _rest) do
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{:ok, {Nix.Cache.Niks3, %{}}}
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end
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def parse_url("attic://" <> rest) do
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{:ok, {Nix.Cache.Attic, %{cache: rest}}}
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end