nix backend: init

Author: vlinkz

src/asgen/backends/nix/nixindexutils.d

@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2025 Victor Fuentes <[email protected]>
+ *
+ * Based on the archlinux and alpinelinux backends, which are:
+ * Copyright (C) 2016 Matthias Klumpp <[email protected]>
+ * Copyright (C) 2020 Rasmus Thomsen <[email protected]>
+ *
+ * Licensed under the GNU Lesser General Public License Version 3
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the license, or
+ * (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this software.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+module asgen.backends.nix.nixindexutils;
+
+import std.file : exists;
+import std.format : format;
+import std.json : parseJSON, JSONValue;
+import std.path : buildPath;
+import std.process : execute, pipeProcess, wait;
+import std.range : empty;
+import std.string : strip;
+
+import glib.Util : Util;
+
+import asgen.downloader : Downloader, DownloadException;
+import asgen.logging : logDebug, logError, logInfo;
+
+immutable(string) downloadNixPackagesIfNecessary (const string channel, const string destFilePath)
+{
+    if (destFilePath.exists) {
+        return destFilePath;
+    }
+
+    auto brotliExe = Util.findProgramInPath("brotli");
+    if (brotliExe.empty) {
+        throw new Exception("brotli binary not found. Cannot extract packages.json.br");
+    }
+
+    auto downloader = Downloader.get;
+
+    immutable filePath = buildPath("https://channels.nixos.org/", channel, "packages.json.br");
+
+    try {
+        downloader.downloadFile(filePath, destFilePath ~ ".br");
+        auto result = execute([brotliExe, "-d", destFilePath ~ ".br", "-o", destFilePath]);
+        if (result.status == 0) {
+            return destFilePath;
+        }
+    } catch (DownloadException e) {
+        logDebug("Unable to download: %s", e.msg);
+    }
+
+    throw new Exception("Failed to download and extract packages.json.br");
+}
+
+immutable(string) buildNixIndexIfNecessary (const string channel, const string arch, const string destFilePath)
+{
+    if ((buildPath(destFilePath, "files")).exists) {
+        return destFilePath;
+    }
+
+    auto nixExe = Util.findProgramInPath("nix");
+    if (nixExe.empty) {
+        throw new Exception("nix binary not found. Cannot extract packages.json.br");
+    }
+    auto nixIndexExe = Util.findProgramInPath("nix-index");
+    if (nixIndexExe.empty) {
+        throw new Exception("nix-index binary not found. Cannot extract packages.json.br");
+    }
+
+    string nixpkgsPath;
+    {
+        auto pipes = pipeProcess([
+            nixExe,
+            "--extra-experimental-features",
+            "nix-command flakes",
+            "eval",
+            format("nixpkgs/%s#path", channel),
+            "--quiet",
+        ]);
+        string stdout_output;
+        string stderr_output;
+        foreach (line; pipes.stdout.byLine) {
+            stdout_output ~= line ~ "\n";
+        }
+        foreach (line; pipes.stderr.byLine) {
+            stderr_output ~= line ~ "\n";
+        }
+        auto result = wait(pipes.pid);
+
+        if (result != 0) {
+            throw new Exception(format("Failed to get nixpkgs path: %s", stderr_output));
+        }
+        nixpkgsPath = stdout_output.strip();
+    }
+
+    logInfo("Building nix-index db, this may take a while");
+    auto pipes = pipeProcess([
+        nixIndexExe,
+        "-f",
+        nixpkgsPath,
+        "-s",
+        arch,
+        "-d",
+        destFilePath,
+    ]);
+    foreach (line; pipes.stderr.byLine) {
+        logDebug("nix-index: %s", line);
+    }
+    auto result = wait(pipes.pid);
+
+    if (result != 0) {
+        throw new Exception("Failed to populate nix index");
+    }
+
+    return destFilePath;
+}
+
+ubyte[] nixStoreCat (const string nixExe, const string storeUrl, const string path)
+{
+    auto pipes = pipeProcess([
+        nixExe,
+        "--extra-experimental-features",
+        "nix-command",
+        "store",
+        "cat",
+        "--store",
+        storeUrl,
+        "--quiet",
+        path,
+    ]);
+    string stdout_output;
+    string stderr_output;
+    foreach (line; pipes.stdout.byLine) {
+        stdout_output ~= line ~ "\n";
+    }
+    foreach (line; pipes.stderr.byLine) {
+        stderr_output ~= line ~ "\n";
+    }
+    auto result = wait(pipes.pid);
+    if (result != 0) {
+        logError("nix store cat failed: %s", stderr_output);
+        return [' '];
+    }
+    return cast(ubyte[]) stdout_output;
+}
+
+immutable(JSONValue) nixStoreLs (const string nixExe, const string storeUrl, const string path)
+{
+    auto pipes = pipeProcess([
+        nixExe,
+        "--extra-experimental-features",
+        "nix-command",
+        "store",
+        "ls",
+        "--store",
+        storeUrl,
+        "--recursive",
+        "--json",
+        "--quiet",
+        path,
+    ]);
+    string stdout_output;
+    string stderr_output;
+    foreach (line; pipes.stdout.byLine) {
+        stdout_output ~= line ~ "\n";
+    }
+    foreach (line; pipes.stderr.byLine) {
+        stderr_output ~= line ~ "\n";
+    }
+    auto result = wait(pipes.pid);
+    if (result != 0) {
+        throw new Exception(format("nix store ls failed: %s", stderr_output));
+    }
+
+    return parseJSON(stdout_output);
+}