diff options
Diffstat (limited to 'nix/buildGo')
| -rw-r--r-- | nix/buildGo/.skip-subtree | 2 | ||||
| -rw-r--r-- | nix/buildGo/README.md | 140 | ||||
| -rw-r--r-- | nix/buildGo/default.nix | 129 | ||||
| -rw-r--r-- | nix/buildGo/example/default.nix | 47 | ||||
| -rw-r--r-- | nix/buildGo/example/lib.go | 9 | ||||
| -rw-r--r-- | nix/buildGo/example/main.go | 25 | ||||
| -rw-r--r-- | nix/buildGo/example/thing.proto | 10 | ||||
| -rw-r--r-- | nix/buildGo/external/default.nix | 95 | ||||
| -rw-r--r-- | nix/buildGo/external/main.go | 186 | ||||
| -rw-r--r-- | nix/buildGo/proto.nix | 84 |
10 files changed, 727 insertions, 0 deletions
diff --git a/nix/buildGo/.skip-subtree b/nix/buildGo/.skip-subtree new file mode 100644 index 000000000000..8db1f814f653 --- /dev/null +++ b/nix/buildGo/.skip-subtree @@ -0,0 +1,2 @@ +Subdirectories of this folder should not be imported since they are +internal to buildGo.nix and incompatible with readTree. diff --git a/nix/buildGo/README.md b/nix/buildGo/README.md new file mode 100644 index 000000000000..37e0c06933f9 --- /dev/null +++ b/nix/buildGo/README.md @@ -0,0 +1,140 @@ +buildGo.nix +=========== + +This is an alternative [Nix][] build system for [Go][]. It supports building Go +libraries and programs, and even automatically generating Protobuf & gRPC +libraries. + +*Note:* This will probably end up being folded into [Nixery][]. + +## Background + +Most language-specific Nix tooling outsources the build to existing +language-specific build tooling, which essentially means that Nix ends up being +a wrapper around all sorts of external build systems. + +However, systems like [Bazel][] take an alternative approach in which the +compiler is invoked directly and the composition of programs and libraries stays +within a single homogeneous build system. + +Users don't need to learn per-language build systems and especially for +companies with large monorepo-setups ([like Google][]) this has huge +productivity impact. + +This project is an attempt to prove that Nix can be used in a similar style to +build software directly, rather than shelling out to other build systems. + +## Example + +Given a program layout like this: + +``` +. +├── lib <-- some library component +│ ├── bar.go +│ └── foo.go +├── api.proto <-- gRPC API definition +├── main.go <-- program implementation +└── default.nix <-- build instructions +``` + +The contents of `default.nix` could look like this: + +```nix +{ buildGo }: + +let + api = buildGo.grpc { + name = "someapi"; + proto = ./api.proto; + }; + + lib = buildGo.package { + name = "somelib"; + srcs = [ + ./lib/bar.go + ./lib/foo.go + ]; + }; +in buildGo.program { + name = "my-program"; + deps = [ api lib ]; + + srcs = [ + ./main.go + ]; +} +``` + +(If you don't know how to read Nix, check out [nix-1p][]) + +## Usage + +`buildGo` exposes five different functions: + +* `buildGo.program`: Build a Go binary out of the specified source files. + + | parameter | type | use | required? | + |-----------|-------------------------|------------------------------------------------|-----------| + | `name` | `string` | Name of the program (and resulting executable) | yes | + | `srcs` | `list<path>` | List of paths to source files | yes | + | `deps` | `list<drv>` | List of dependencies (i.e. other Go libraries) | no | + | `x_defs` | `attrs<string, string>` | Attribute set of linker vars (i.e. `-X`-flags) | no | + +* `buildGo.package`: Build a Go library out of the specified source files. + + | parameter | type | use | required? | + |-----------|--------------|------------------------------------------------|-----------| + | `name` | `string` | Name of the library | yes | + | `srcs` | `list<path>` | List of paths to source files | yes | + | `deps` | `list<drv>` | List of dependencies (i.e. other Go libraries) | no | + | `path` | `string` | Go import path for the resulting library | no | + +* `buildGo.external`: Build an externally defined Go library or program. + + This function performs analysis on the supplied source code (which + can use the standard Go tooling layout) and creates a tree of all + the packages contained within. + + This exists for compatibility with external libraries that were not + defined using buildGo. + + | parameter | type | use | required? | + |-----------|----------------|-----------------------------------------------|-----------| + | `path` | `string` | Go import path for the resulting package | yes | + | `src` | `path` | Path to the source **directory** | yes | + | `deps` | `list<drv>` | List of dependencies (i.e. other Go packages) | no | + + For some examples of how `buildGo.external` is used, check out + [`proto.nix`](./proto.nix). + +* `buildGo.proto`: Build a Go library out of the specified Protobuf definition. + + | parameter | type | use | required? | + |-------------|-------------|--------------------------------------------------|-----------| + | `name` | `string` | Name for the resulting library | yes | + | `proto` | `path` | Path to the Protobuf definition file | yes | + | `path` | `string` | Import path for the resulting Go library | no | + | `extraDeps` | `list<drv>` | Additional Go dependencies to add to the library | no | + +* `buildGo.grpc`: Build a Go library out of the specified gRPC definition. + + The parameters are identical to `buildGo.proto`. + +## Current status + +This project is work-in-progress. Crucially it is lacking the following features: + +* feature flag parity with Bazel's Go rules +* documentation building +* test execution + +There are still some open questions around how to structure some of those +features in Nix. + +[Nix]: https://nixos.org/nix/ +[Go]: https://golang.org/ +[Nixery]: https://github.com/google/nixery +[Bazel]: https://bazel.build/ +[like Google]: https://ai.google/research/pubs/pub45424 +[nix-1p]: https://github.com/tazjin/nix-1p diff --git a/nix/buildGo/default.nix b/nix/buildGo/default.nix new file mode 100644 index 000000000000..03c0b2bc4b9d --- /dev/null +++ b/nix/buildGo/default.nix @@ -0,0 +1,129 @@ +# 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 <nixpkgs> {} +, ... }: + +let + inherit (builtins) + attrNames + baseNameOf + dirOf + elemAt + filter + listToAttrs + map + match + readDir + replaceStrings + toString; + + inherit (pkgs) lib go runCommand fetchFromGitHub protobuf symlinkJoin; + + # 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)); + }; + + # High-level build functions + + # Build a Go program out of the specified files and dependencies. + program = { name, srcs, deps ? [], x_defs ? {} }: + let uniqueDeps = allDeps deps; + in runCommand name {} '' + ${go}/bin/go tool compile -o ${name}.a -trimpath=$PWD -trimpath=${go} ${includeSources uniqueDeps} ${spaceOut srcs} + mkdir -p $out/bin + export GOROOT_FINAL=go + ${go}/bin/go tool link -o $out/bin/${name} -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 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 -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 -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 + ''; + in (runCommand "golib-${name}" {} '' + mkdir -p $out/${path} + ${srcList path (map (s: "${s}") srcs)} + ${asmBuild} + ${go}/bin/go tool compile -pack ${asmLink} -o $out/${path}.a -trimpath=$PWD -trimpath=${go} -p ${path} ${includeSources uniqueDeps} ${spaceOut srcs} + ${asmPack} + '') // { goDeps = uniqueDeps; goImportPath = path; }; + + # Build a tree of Go libraries out of an external Go source + # directory that follows the standard Go layout and was not built + # with buildGo.nix. + # + # The derivation for each actual package will reside in an attribute + # named "gopkg", and an attribute named "gobin" for binaries. + external = import ./external { inherit pkgs program package; }; + + # Import support libraries needed for protobuf & gRPC support + protoLibs = import ./proto.nix { + inherit external; + }; + + # Build a Go library out of the specified protobuf definition. + proto = { name, proto, path ? name, extraDeps ? [] }: (makeOverridable package) { + inherit name path; + deps = [ protoLibs.goProto.proto.gopkg ] ++ extraDeps; + srcs = lib.singleton (runCommand "goproto-${name}.pb.go" {} '' + cp ${proto} ${baseNameOf proto} + ${protobuf}/bin/protoc --plugin=${protoLibs.goProto.protoc-gen-go.gopkg}/bin/protoc-gen-go \ + --go_out=plugins=grpc,import_path=${baseNameOf path}:. ${baseNameOf proto} + mv *.pb.go $out + ''); + }; + + # Build a Go library out of the specified gRPC definition. + grpc = args: proto (args // { extraDeps = [ protoLibs.goGrpc.gopkg ]; }); + +in { + # Only the high-level builder functions are exposed, but made + # overrideable. + program = makeOverridable program; + package = makeOverridable package; + proto = makeOverridable proto; + grpc = makeOverridable grpc; + external = makeOverridable external; +} diff --git a/nix/buildGo/example/default.nix b/nix/buildGo/example/default.nix new file mode 100644 index 000000000000..5abed1fbbcb5 --- /dev/null +++ b/nix/buildGo/example/default.nix @@ -0,0 +1,47 @@ +# Copyright 2019 Google LLC. +# SPDX-License-Identifier: Apache-2.0 + +# This file provides examples for how to use the various builder +# functions provided by `buildGo`. +# +# The features used in the example are not exhaustive, but should give +# users a quick introduction to how to use buildGo. + +let + buildGo = import ../buildGo.nix {}; + + # Example use of buildGo.package, which creates an importable Go + # package from the specified source files. + examplePackage = buildGo.package { + name = "example"; + srcs = [ + ./lib.go + ]; + }; + + # Example use of buildGo.proto, which generates a Go library from a + # Protobuf definition file. + exampleProto = buildGo.proto { + name = "exampleproto"; + proto = ./thing.proto; + }; + + # Example use of buildGo.program, which builds an executable using + # the specified name and dependencies (which in turn must have been + # created via buildGo.package etc.) +in buildGo.program { + name = "example"; + + srcs = [ + ./main.go + ]; + + deps = [ + examplePackage + exampleProto + ]; + + x_defs = { + "main.Flag" = "successfully"; + }; +} diff --git a/nix/buildGo/example/lib.go b/nix/buildGo/example/lib.go new file mode 100644 index 000000000000..8a61370e994c --- /dev/null +++ b/nix/buildGo/example/lib.go @@ -0,0 +1,9 @@ +// Copyright 2019 Google LLC. +// SPDX-License-Identifier: Apache-2.0 + +package example + +// UUID returns a totally random, carefully chosen UUID +func UUID() string { + return "3640932f-ad40-4bc9-b45d-f504a0f5910a" +} diff --git a/nix/buildGo/example/main.go b/nix/buildGo/example/main.go new file mode 100644 index 000000000000..bbcedbff8726 --- /dev/null +++ b/nix/buildGo/example/main.go @@ -0,0 +1,25 @@ +// Copyright 2019 Google LLC. +// SPDX-License-Identifier: Apache-2.0 +// +// Package main provides a tiny example program for the Bazel-style +// Nix build system for Go. + +package main + +import ( + "example" + "exampleproto" + "fmt" +) + +var Flag string = "unsuccessfully" + +func main() { + thing := exampleproto.Thing{ + Id: example.UUID(), + KindOfThing: "test thing", + } + + fmt.Printf("The thing is a %s with ID %q\n", thing.Id, thing.KindOfThing) + fmt.Printf("The flag has been %s set\n", Flag) +} diff --git a/nix/buildGo/example/thing.proto b/nix/buildGo/example/thing.proto new file mode 100644 index 000000000000..0cb34124dfb9 --- /dev/null +++ b/nix/buildGo/example/thing.proto @@ -0,0 +1,10 @@ +// Copyright 2019 Google LLC. +// SPDX-License-Identifier: Apache-2.0 + +syntax = "proto3"; +package exampleProto; + +message Thing { + string id = 1; + string kind_of_thing = 2; +} diff --git a/nix/buildGo/external/default.nix b/nix/buildGo/external/default.nix new file mode 100644 index 000000000000..48f678688eec --- /dev/null +++ b/nix/buildGo/external/default.nix @@ -0,0 +1,95 @@ +# Copyright 2019 Google LLC. +# SPDX-License-Identifier: Apache-2.0 +{ pkgs, program, package }: + +let + inherit (builtins) + elemAt + foldl' + fromJSON + head + length + listToAttrs + readFile + replaceStrings + tail + throw; + + inherit (pkgs) lib runCommand go jq ripgrep; + + pathToName = p: replaceStrings ["/"] ["_"] (toString p); + + # Collect all non-vendored dependencies from the Go standard library + # into a file that can be used to filter them out when processing + # dependencies. + stdlibPackages = runCommand "stdlib-pkgs.json" {} '' + export HOME=$PWD + export GOPATH=/dev/null + ${go}/bin/go list all | \ + ${ripgrep}/bin/rg -v 'vendor' | \ + ${jq}/bin/jq -R '.' | \ + ${jq}/bin/jq -c -s 'map({key: ., value: true}) | from_entries' \ + > $out + ''; + + analyser = program { + name = "analyser"; + + srcs = [ + ./main.go + ]; + + x_defs = { + "main.stdlibList" = "${stdlibPackages}"; + }; + }; + + mkset = path: value: + if path == [] then { gopkg = value; } + else { "${head path}" = mkset (tail path) value; }; + + last = l: elemAt l ((length l) - 1); + + toPackage = self: src: path: depMap: entry: + let + localDeps = map (d: lib.attrByPath (d ++ [ "gopkg" ]) ( + throw "missing local dependency '${lib.concatStringsSep "." d}' in '${path}'" + ) self) entry.localDeps; + + foreignDeps = map (d: lib.attrByPath [ d ] ( + throw "missing foreign dependency '${d}' in '${path}'" + ) depMap) entry.foreignDeps; + + args = { + srcs = map (f: src + ("/" + f)) entry.files; + deps = localDeps ++ foreignDeps; + }; + + libArgs = args // { + name = pathToName entry.name; + path = lib.concatStringsSep "/" ([ path ] ++ entry.locator); + sfiles = map (f: src + ("/" + f)) entry.sfiles; + }; + + binArgs = args // { + name = (last ((lib.splitString "/" path) ++ entry.locator)); + }; + in if entry.isCommand then (program binArgs) else (package libArgs); + +in { src, path, deps ? [] }: let + # Build a map of dependencies (from their import paths to their + # derivation) so that they can be conditionally imported only in + # sub-packages that require them. + depMap = listToAttrs (map (d: { + name = d.goImportPath; + value = d; + }) deps); + + name = pathToName path; + analysisOutput = runCommand "${name}-structure.json" {} '' + ${analyser}/bin/analyser -path ${path} -source ${src} > $out + ''; + analysis = fromJSON (readFile analysisOutput); +in lib.fix(self: foldl' lib.recursiveUpdate {} ( + map (entry: mkset entry.locator (toPackage self src path depMap entry)) analysis +)) diff --git a/nix/buildGo/external/main.go b/nix/buildGo/external/main.go new file mode 100644 index 000000000000..aa4a813d32bd --- /dev/null +++ b/nix/buildGo/external/main.go @@ -0,0 +1,186 @@ +// Copyright 2019 Google LLC. +// SPDX-License-Identifier: Apache-2.0 + +// This tool analyses external (i.e. not built with `buildGo.nix`) Go +// packages to determine a build plan that Nix can import. +package main + +import ( + "encoding/json" + "flag" + "fmt" + "go/build" + "io/ioutil" + "log" + "os" + "path" + "path/filepath" + "strings" +) + +// Path to a JSON file describing all standard library import paths. +// This file is generated and set here by Nix during the build +// process. +var stdlibList string + +// pkg describes a single Go package within the specified source +// directory. +// +// Return information includes the local (relative from project root) +// and external (none-stdlib) dependencies of this package. +type pkg struct { + Name string `json:"name"` + Locator []string `json:"locator"` + Files []string `json:"files"` + SFiles []string `json:"sfiles"` + LocalDeps [][]string `json:"localDeps"` + ForeignDeps []string `json:"foreignDeps"` + IsCommand bool `json:"isCommand"` +} + +// findGoDirs returns a filepath.WalkFunc that identifies all +// directories that contain Go source code in a certain tree. +func findGoDirs(at string) ([]string, error) { + dirSet := make(map[string]bool) + + err := filepath.Walk(at, func(path string, info os.FileInfo, err error) error { + name := info.Name() + // Skip folders that are guaranteed to not be relevant + if info.IsDir() && (name == "testdata" || name == ".git") { + return filepath.SkipDir + } + + // If the current file is a Go file, then the directory is popped + // (i.e. marked as a Go directory). + if !info.IsDir() && strings.HasSuffix(name, ".go") && !strings.HasSuffix(name, "_test.go") { + dirSet[filepath.Dir(path)] = true + } + + return nil + }) + + if err != nil { + return nil, err + } + + goDirs := []string{} + for k, _ := range dirSet { + goDirs = append(goDirs, k) + } + + return goDirs, nil +} + +// analysePackage loads and analyses the imports of a single Go +// package, returning the data that is required by the Nix code to +// generate a derivation for this package. +func analysePackage(root, source, importpath string, stdlib map[string]bool) (pkg, error) { + ctx := build.Default + ctx.CgoEnabled = false + + p, err := ctx.ImportDir(source, build.IgnoreVendor) + if err != nil { + return pkg{}, err + } + + local := [][]string{} + foreign := []string{} + + for _, i := range p.Imports { + if stdlib[i] { + continue + } + + if i == importpath { + local = append(local, []string{}) + } else if strings.HasPrefix(i, importpath) { + local = append(local, strings.Split(strings.TrimPrefix(i, importpath+"/"), "/")) + } else { + foreign = append(foreign, i) + } + } + + prefix := strings.TrimPrefix(source, root+"/") + + locator := []string{} + if len(prefix) != len(source) { + locator = strings.Split(prefix, "/") + } else { + // Otherwise, the locator is empty since its the root package and + // no prefix should be added to files. + prefix = "" + } + + files := []string{} + for _, f := range p.GoFiles { + files = append(files, path.Join(prefix, f)) + } + + sfiles := []string{} + for _, f := range p.SFiles { + sfiles = append(sfiles, path.Join(prefix, f)) + } + + return pkg{ + Name: path.Join(importpath, prefix), + Locator: locator, + Files: files, + SFiles: sfiles, + LocalDeps: local, + ForeignDeps: foreign, + IsCommand: p.IsCommand(), + }, nil +} + +func loadStdlibPkgs(from string) (pkgs map[string]bool, err error) { + f, err := ioutil.ReadFile(from) + if err != nil { + return + } + + err = json.Unmarshal(f, &pkgs) + return +} + +func main() { + source := flag.String("source", "", "path to directory with sources to process") + path := flag.String("path", "", "import path for the package") + + flag.Parse() + + if *source == "" { + log.Fatalf("-source flag must be specified") + } + + stdlibPkgs, err := loadStdlibPkgs(stdlibList) + if err != nil { + log.Fatalf("failed to load standard library index from %q: %s\n", stdlibList, err) + } + + goDirs, err := findGoDirs(*source) + if err != nil { + log.Fatalf("failed to walk source directory '%s': %s\n", source, err) + } + + all := []pkg{} + for _, d := range goDirs { + analysed, err := analysePackage(*source, d, *path, stdlibPkgs) + + // If the Go source analysis returned "no buildable Go files", + // that directory should be skipped. + // + // This might be due to `+build` flags on the platform and other + // reasons (such as test files). + if _, ok := err.(*build.NoGoError); ok { + continue + } + + if err != nil { + log.Fatalf("failed to analyse package at %q: %s", d, err) + } + all = append(all, analysed) + } + + j, _ := json.Marshal(all) + fmt.Println(string(j)) +} diff --git a/nix/buildGo/proto.nix b/nix/buildGo/proto.nix new file mode 100644 index 000000000000..2ece948ebd84 --- /dev/null +++ b/nix/buildGo/proto.nix @@ -0,0 +1,84 @@ +# Copyright 2019 Google LLC. +# SPDX-License-Identifier: Apache-2.0 +# +# This file provides derivations for the dependencies of a gRPC +# service in Go. + +{ external }: + +let + inherit (builtins) fetchGit map; +in rec { + goProto = external { + path = "github.com/golang/protobuf"; + src = fetchGit { + url = "https://github.com/golang/protobuf"; + rev = "ed6926b37a637426117ccab59282c3839528a700"; + }; + }; + + xnet = external { + path = "golang.org/x/net"; + + src = fetchGit { + url = "https://go.googlesource.com/net"; + rev = "ffdde105785063a81acd95bdf89ea53f6e0aac2d"; + }; + + deps = map (p: p.gopkg) [ + xtext.secure.bidirule + xtext.unicode.bidi + xtext.unicode.norm + ]; + }; + + xsys = external { + path = "golang.org/x/sys"; + src = fetchGit { + url = "https://go.googlesource.com/sys"; + rev = "bd437916bb0eb726b873ee8e9b2dcf212d32e2fd"; + }; + }; + + xtext = external { + path = "golang.org/x/text"; + src = fetchGit { + url = "https://go.googlesource.com/text"; + rev = "cbf43d21aaebfdfeb81d91a5f444d13a3046e686"; + }; + }; + + genproto = external { + path = "google.golang.org/genproto"; + src = fetchGit { + url = "https://github.com/google/go-genproto"; + rev = "83cc0476cb11ea0da33dacd4c6354ab192de6fe6"; + }; + + deps = with goProto; map (p: p.gopkg) [ + proto + ptypes.any + ]; + }; + + goGrpc = external { + path = "google.golang.org/grpc"; + deps = map (p: p.gopkg) ([ + xnet.trace + xnet.http2 + xsys.unix + xnet.http2.hpack + genproto.googleapis.rpc.status + ] ++ (with goProto; [ + proto + ptypes + ptypes.duration + ptypes.timestamp + ])); + + src = fetchGit { + url = "https://github.com/grpc/grpc-go"; + rev = "d8e3da36ac481ef00e510ca119f6b68177713689"; + }; + }; +} |