# Copyright 2019 Google LLC. # SPDX-License-Identifier: Apache-2.0 # # buildGo provides Nix functions to build Go packages in the style of Bazel's # rules_go. { pkgs ? import { } , ... }: let inherit (builtins) attrNames baseNameOf dirOf elemAt filter listToAttrs map match readDir replaceStrings toString; inherit (pkgs) lib runCommand fetchFromGitHub protobuf symlinkJoin go; goStdlib = buildStdlib go; # Helpers for low-level Go compiler invocations spaceOut = lib.concatStringsSep " "; includeDepSrc = dep: "-I ${dep}"; includeSources = deps: spaceOut (map includeDepSrc deps); includeDepLib = dep: "-L ${dep}"; includeLibs = deps: spaceOut (map includeDepLib deps); srcBasename = src: elemAt (match "([a-z0-9]{32}\-)?(.*\.go)" (baseNameOf src)) 1; srcCopy = path: src: "cp ${src} $out/${path}/${srcBasename src}"; srcList = path: srcs: lib.concatStringsSep "\n" (map (srcCopy path) srcs); allDeps = deps: lib.unique (lib.flatten (deps ++ (map (d: d.goDeps) deps))); xFlags = x_defs: spaceOut (map (k: "-X ${k}=${x_defs."${k}"}") (attrNames x_defs)); pathToName = p: replaceStrings [ "/" ] [ "_" ] (toString p); # Add an `overrideGo` attribute to a function result that works # similar to `overrideAttrs`, but is used specifically for the # arguments passed to Go builders. makeOverridable = f: orig: (f orig) // { overrideGo = new: makeOverridable f (orig // (new orig)); }; buildStdlib = go: runCommand "go-stdlib-${go.version}" { nativeBuildInputs = [ go ]; } '' HOME=$NIX_BUILD_TOP/home mkdir $HOME goroot="$(go env GOROOT)" cp -R "$goroot/src" "$goroot/pkg" . chmod -R +w . GODEBUG=installgoroot=all GOROOT=$NIX_BUILD_TOP go install -v --trimpath std mkdir $out cp -r pkg/*_*/* $out find $out -name '*.a' | while read -r ARCHIVE_FULL; do ARCHIVE="''${ARCHIVE_FULL#"$out/"}" PACKAGE="''${ARCHIVE%.a}" echo "packagefile $PACKAGE=$ARCHIVE_FULL" done > $out/importcfg ''; importcfgCmd = { name, deps, out ? "importcfg" }: '' echo "# nix buildGo ${name}" > "${out}" cat "${goStdlib}/importcfg" >> "${out}" ${lib.concatStringsSep "\n" (map (dep: '' find "${dep}" -name '*.a' | while read -r pkgp; do relpath="''${pkgp#"${dep}/"}" pkgname="''${relpath%.a}" echo "packagefile $pkgname=$pkgp" done >> "${out}" '') deps)} ''; # High-level build functions # Build a Go program out of the specified files and dependencies. program = { name, srcs, deps ? [ ], x_defs ? { } }: let uniqueDeps = allDeps (map (d: d.gopkg) deps); in runCommand name { } '' ${importcfgCmd { inherit name; deps = uniqueDeps; }} ${go}/bin/go tool compile -o ${name}.a -importcfg=importcfg -trimpath=$PWD -trimpath=${go} -p main ${includeSources uniqueDeps} ${spaceOut srcs} mkdir -p $out/bin export GOROOT_FINAL=go ${go}/bin/go tool link -o $out/bin/${name} -importcfg=importcfg -buildid nix ${xFlags x_defs} ${includeLibs uniqueDeps} ${name}.a ''; # Build a Go library assembled out of the specified files. # # This outputs both the sources and compiled binary, as both are # needed when downstream packages depend on it. package = { name, srcs, deps ? [ ], path ? name, sfiles ? [ ] }: let uniqueDeps = allDeps (map (d: d.gopkg) deps); # The build steps below need to be executed conditionally for Go # assembly if the analyser detected any *.s files. # # This is required for several popular packages (e.g. x/sys). ifAsm = do: lib.optionalString (sfiles != [ ]) do; asmBuild = ifAsm '' ${go}/bin/go tool asm -p ${path} -trimpath $PWD -I $PWD -I ${go}/share/go/pkg/include -D GOOS_linux -D GOARCH_amd64 -gensymabis -o ./symabis ${spaceOut sfiles} ${go}/bin/go tool asm -p ${path} -trimpath $PWD -I $PWD -I ${go}/share/go/pkg/include -D GOOS_linux -D GOARCH_amd64 -o ./asm.o ${spaceOut sfiles} ''; asmLink = ifAsm "-symabis ./symabis -asmhdr $out/go_asm.h"; asmPack = ifAsm '' ${go}/bin/go tool pack r $out/${path}.a ./asm.o ''; gopkg = (runCommand "golib-${name}" { } '' mkdir -p $out/${path} ${srcList path (map (s: "${s}") srcs)} ${asmBuild} ${importcfgCmd { inherit name; deps = uniqueDeps; }} ${go}/bin/go tool compile -pack ${asmLink} -o $out/${path}.a -importcfg=importcfg -trimpath=$PWD -trimpath=${go} -p ${path} ${includeSources uniqueDeps} ${spaceOut srcs} ${asmPack} '').overrideAttrs (_: { passthru = { inherit gopkg; goDeps = uniqueDeps; goImportPath = path; }; }); in gopkg; # Build a tree of Go libraries out of an external Go source # directory that follows the standard Go layout and was not built # with buildGo.nix. # # The derivation for each actual package will reside in an attribute # named "gopkg", and an attribute named "gobin" for binaries. external = import ./external { inherit pkgs program package; }; in { # Only the high-level builder functions are exposed, but made # overrideable. program = makeOverridable program; package = makeOverridable package; external = makeOverridable external; # re-expose the Go version used inherit go; }