lambda-zig/lambdabuild/Package.zig
2024-08-29 13:56:35 -07:00

159 lines
6.6 KiB
Zig

const std = @import("std");
const Package = @This();
step: std.Build.Step,
options: Options,
/// This is set as part of the make phase, and is the location in the cache
/// for the lambda package. The package will also be copied to the output
/// directory, but this location makes for a good cache key for deployments
zipfile_cache_dest: ?[]const u8 = null,
zipfile_dest: ?[]const u8 = null,
const base_id: std.Build.Step.Id = .install_file;
pub const Options = struct {
name: []const u8 = "",
exe: *std.Build.Step.Compile,
zipfile_name: []const u8 = "function.zip",
};
pub fn create(owner: *std.Build, options: Options) *Package {
const name = owner.dupe(options.name);
const step_name = owner.fmt("{s} {s}{s}", .{
"aws lambda",
"package",
name,
});
const package = owner.allocator.create(Package) catch @panic("OOM");
package.* = .{
.step = std.Build.Step.init(.{
.id = base_id,
.name = step_name,
.owner = owner,
.makeFn = make,
}),
.options = options,
};
return package;
}
pub fn shasumFilePath(self: Package) ![]const u8 {
return try std.fmt.allocPrint(
self.step.owner.allocator,
"{s}{s}{s}",
.{ std.fs.path.dirname(self.zipfile_cache_dest.?).?, std.fs.path.sep_str, "sha256sum.txt" },
);
}
pub fn packagedFilePath(self: Package) []const u8 {
return self.step.owner.getInstallPath(.prefix, self.options.zipfile_name);
}
pub fn packagedFileLazyPath(self: Package) std.Build.LazyPath {
return .{ .src_path = .{
.owner = self.step.owner,
.sub_path = self.step.owner.getInstallPath(.prefix, self.options.zipfile_name),
} };
}
fn make(step: *std.Build.Step, node: std.Progress.Node) anyerror!void {
_ = node;
const self: *Package = @fieldParentPtr("step", step);
// get a hash of the bootstrap and whatever other files we put into the zip
// file (because a zip is not really reproducible). That hash becomes the
// cache directory, similar to the way rest of zig works
//
// Otherwise, create the package in our cache indexed by hash, and copy
// our bootstrap, zip things up and install the file into zig-out
const bootstrap = bootstrapLocation(self.*) catch |e| {
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
return step.fail("Could not copy output to bootstrap: {}", .{e});
};
const bootstrap_dirname = std.fs.path.dirname(bootstrap).?;
const zipfile_src = try std.fs.path.join(step.owner.allocator, &[_][]const u8{ bootstrap_dirname, self.options.zipfile_name });
self.zipfile_cache_dest = zipfile_src;
self.zipfile_dest = self.step.owner.getInstallPath(.prefix, self.options.zipfile_name);
if (std.fs.copyFileAbsolute(zipfile_src, self.zipfile_dest.?, .{})) |_| {
// we're good here. The zip file exists in cache and has been copied
step.result_cached = true;
} else |_| {
// error, but this is actually the normal case. We will zip the file
// using system zip and store that in cache with the output file for later
// use
// TODO: For Windows, tar.exe can actually do zip files.
// tar -a -cf function.zip file1 [file2...]
//
// See: https://superuser.com/questions/201371/create-zip-folder-from-the-command-line-windows#comment2725283_898508
var child = std.process.Child.init(&[_][]const u8{
"zip",
"-qj9X",
zipfile_src,
bootstrap,
}, self.step.owner.allocator);
child.stdout_behavior = .Ignore;
child.stdin_behavior = .Ignore; // we'll allow stderr through
switch (try child.spawnAndWait()) {
.Exited => |rc| if (rc != 0) return step.fail("Non-zero exit code {} from zip", .{rc}),
.Signal, .Stopped, .Unknown => return step.fail("Abnormal termination from zip step", .{}),
}
try std.fs.copyFileAbsolute(zipfile_src, self.zipfile_dest.?, .{}); // It better be there now
// One last thing. We want to get a Sha256 sum of the zip file, and
// store it in cache. This will help the deployment process compare
// to what's out in AWS, since revision id is apparently trash for these
// purposes
const zipfile = try std.fs.openFileAbsolute(zipfile_src, .{});
defer zipfile.close();
const zip_bytes = try zipfile.readToEndAlloc(step.owner.allocator, 100 * 1024 * 1024);
var hash: [std.crypto.hash.sha2.Sha256.digest_length]u8 = undefined;
std.crypto.hash.sha2.Sha256.hash(zip_bytes, &hash, .{});
const base64 = std.base64.standard.Encoder;
var encoded: [base64.calcSize(std.crypto.hash.sha2.Sha256.digest_length)]u8 = undefined;
const shaoutput = try std.fs.createFileAbsolute(try self.shasumFilePath(), .{});
defer shaoutput.close();
try shaoutput.writeAll(base64.encode(encoded[0..], hash[0..]));
}
}
fn bootstrapLocation(package: Package) ![]const u8 {
const output = package.step.owner.getInstallPath(.bin, package.options.exe.out_filename);
// We will always copy the output file, mainly because we also need the hash...
// if (std.mem.eql(u8, "bootstrap", package.options.exe.out_filename))
// return output; // easy path
// Not so easy...read the file, get a hash of contents, see if it's in cache
const output_file = try std.fs.openFileAbsolute(output, .{});
defer output_file.close();
const output_bytes = try output_file.readToEndAlloc(package.step.owner.allocator, 100 * 1024 * 1024); // 100MB file
// std.Build.Cache.Hasher
// std.Buidl.Cache.hasher_init
var hasher = std.Build.Cache.HashHelper{}; // We'll reuse the same file hasher from cache
hasher.addBytes(output_bytes);
const hash = std.fmt.bytesToHex(hasher.hasher.finalResult(), .lower);
const dest_path = try package.step.owner.cache_root.join(
package.step.owner.allocator,
&[_][]const u8{ "p", hash[0..], "bootstrap" },
);
const dest_file = std.fs.openFileAbsolute(dest_path, .{}) catch null;
if (dest_file) |d| {
d.close();
return dest_path;
}
const pkg_path = try package.step.owner.cache_root.join(
package.step.owner.allocator,
&[_][]const u8{"p"},
);
// Destination file does not exist. Write the bootstrap (after creating the directory)
std.fs.makeDirAbsolute(pkg_path) catch {};
std.fs.makeDirAbsolute(std.fs.path.dirname(dest_path).?) catch {};
const write_file = try std.fs.createFileAbsolute(dest_path, .{});
defer write_file.close();
try write_file.writeAll(output_bytes);
return dest_path;
}