feat: add "ftl init" with an initial scaffolder for Go (#491)

Will add Kotlin in a followup.

This currently works, but `ftl-go deploy` needs to be adjusted to
support go.mod in the same directory as ftl.toml.

```
ftl init go ./examples/foo --go-module=github.com/TBD54566975/ftl/examples/foo
```

.gitignore

@@ -12,5 +12,5 @@ reflex.conf
 /node_modules
 *.tsbuildinfo
 generated_ftl_module.go
-
+scaffolding.zip
 dist/

Bitfile

@@ -44,12 +44,27 @@ NODE_MODULES_IN = console/client/package{,-lock}.json
   build: install -m 0700 -d %{OUT}
 
 # Build all binaries
-implicit %{RELEASE}/%{1}: cmd/*
-  inputs: %{RELEASE} %{GO_SOURCES} %{CLIENT_OUT}
-  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/%{1}
+# implicit %{RELEASE}/%{1}: cmd/*
+#   inputs: %{RELEASE} %{GO_SOURCES} %{CLIENT_OUT}
+#   build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/%{1}
 
-#%{RELEASE}/ftl-controller: %{RELEASE} %{GO_SOURCES} %{CLIENT_OUT}
-#  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/ftl-controller
+%{RELEASE}/ftl-controller: %{RELEASE} %{GO_SOURCES} %{CLIENT_OUT} cmd/ftl-controller/**/*.go
+  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/ftl-controller
+
+%{RELEASE}/ftl-runner: %{RELEASE} %{GO_SOURCES} cmd/ftl-runner/**/*.go
+  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/ftl-runner
+
+%{RELEASE}/ftl: %{RELEASE} %{GO_SOURCES} cmd/ftl/**/*.go go-runtime/scaffolding.zip
+  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/ftl
+
+%{RELEASE}/ftl-initdb: %{RELEASE} %{GO_SOURCES} cmd/ftl-initdb/**/*.go
+  build: go build -o %{OUT} -tags release -ldflags "-X main.version=%{VERSION} -X main.timestamp=$(date +%s)" ./cmd/ftl-initdb
+
+# Release builds include zipped scaffolding becaused raw go:embed doesn't
+# preserve permissions or symlinks. Irritating.
+go-runtime/scaffolding.zip: go-runtime/scaffolding/*
+  cd go-runtime/scaffolding
+  build: zip -q --symlinks -r ../scaffolding.zip .
 
 %{SCHEMA_OUT}: %{SCHEMA_IN}
   build:

Makefile

@@ -56,6 +56,10 @@ release: build/release/ftl-controller build/release/ftl-runner build/release/ftl
 build/release/%: console/client/dist/index.html
 	go build -o $@ -tags release -ldflags "-X main.version=$(VERSION) -X main.timestamp=$(shell date +%s)" ./cmd/$(shell basename $@)
 
+build/release/ftl:
+	cd go-runtime/scaffolding && zip -q --symlinks -r ../scaffolding.zip .
+	go build -o $@ -tags release -ldflags "-X main.version=$(VERSION) -X main.timestamp=$(shell date +%s)" ./cmd/ftl
+
 $(KT_MVN_OUT): $(KT_RUNTIME_IN)
 	mvn -pl :ftl-runtime clean package
 

cmd/ftl/cmd_init.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+
+	"github.com/alecthomas/errors"
+
+	"github.com/TBD54566975/ftl/backend/common/exec"
+	"github.com/TBD54566975/ftl/backend/common/log"
+	goruntime "github.com/TBD54566975/ftl/go-runtime"
+	"github.com/TBD54566975/ftl/internal"
+)
+
+type initCmd struct {
+	Hermit bool          `default:"true" help:"Include Hermit language-specific toolchain binaries in the module." negatable:""`
+	Go     initGoCmd     `cmd:"" help:"Initialize a new FTL Go module."`
+	Kotlin initKotlinCmd `cmd:"" help:"Initialize a new FTL Kotlin module."`
+}
+
+type initGoCmd struct {
+	Dir      string `arg:"" default:"." type:"dir" help:"Directory to initialize the module in."`
+	Name     string `help:"Name of the FTL module (defaults to name of directory)."`
+	GoModule string `required:"" help:"Go module path."`
+}
+
+func (i initGoCmd) Run(ctx context.Context, parent *initCmd) error {
+	if i.Name == "" {
+		i.Name = filepath.Base(i.Dir)
+	}
+	if err := internal.Scaffold(goruntime.Files, i.Dir, i); err != nil {
+		return errors.WithStack(err)
+	}
+	if !parent.Hermit {
+		if err := os.RemoveAll(filepath.Join(i.Dir, "bin")); err != nil {
+			return errors.WithStack(err)
+		}
+	}
+	if err := exec.Command(ctx, log.Info, i.Dir, "go", "mod", "tidy").Run(); err != nil {
+		return errors.WithStack(err)
+	}
+	return nil
+}
+
+type initKotlinCmd struct {
+	Dir string `arg:"" default:"." help:"Directory to initialize the module in."`
+}
+
+func (i *initKotlinCmd) Run() error {
+	panic("??")
+}

cmd/ftl/main.go

@@ -29,6 +29,7 @@ type CLI struct {
 	Authenticators map[string]string `help:"Authenticators to use for FTL endpoints." mapsep:"," env:"FTL_AUTHENTICATORS" placeholder:"HOST=EXE,…"`
 
 	Status   statusCmd   `cmd:"" help:"Show FTL status."`
+	Init     initCmd     `cmd:"" help:"Initialize a new FTL module."`
 	PS       psCmd       `cmd:"" help:"List deployments."`
 	Serve    serveCmd    `cmd:"" help:"Start the FTL server."`
 	Call     callCmd     `cmd:"" help:"Call an FTL function."`

go-runtime/devel.go

@@ -0,0 +1,22 @@
+//go:build !release
+
+package goruntime
+
+import (
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// Files is the FTL Go runtime scaffolding files.
+var Files = func() fs.FS {
+	cmd := exec.Command("git", "rev-parse", "--show-toplevel")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		panic(err)
+	}
+	dir := filepath.Join(strings.TrimSpace(string(out)), "go-runtime", "scaffolding")
+	return os.DirFS(dir)
+}()

go-runtime/release.go

@@ -0,0 +1,25 @@
+//go:build release
+
+package goruntime
+
+import (
+	"archive/zip"
+	"bytes"
+	_ "embed"
+	"io/fs"
+)
+
+//go:embed scaffolding.zip
+var archive []byte
+
+// Files is the FTL Go runtime scaffolding files.
+//
+// scaffolding.zip can be generated by running `bit go-runtime/scaffolding.zip`
+// or indirectly via `bit build/release/ftl`.
+var Files fs.FS = func() fs.FS {
+	zr, err := zip.NewReader(bytes.NewReader(archive), int64(len(archive)))
+	if err != nil {
+		panic(err)
+	}
+	return zr
+}()

go-runtime/scaffolding/bin/.go-1.21.3.pkg

@@ -0,0 +1 @@
+hermit

go-runtime/scaffolding/bin/README.hermit.md

@@ -0,0 +1,7 @@
+# Hermit environment
+
+This is a [Hermit](https://github.com/cashapp/hermit) bin directory.
+
+The symlinks in this directory are managed by Hermit and will automatically
+download and install Hermit itself as well as packages. These packages are
+local to this environment.

go-runtime/scaffolding/bin/activate-hermit

@@ -0,0 +1,21 @@
+#!/bin/bash
+# This file must be used with "source bin/activate-hermit" from bash or zsh.
+# You cannot run it directly
+#
+# THIS FILE IS GENERATED; DO NOT MODIFY
+
+if [ "${BASH_SOURCE-}" = "$0" ]; then
+  echo "You must source this script: \$ source $0" >&2
+  exit 33
+fi
+
+BIN_DIR="$(dirname "${BASH_SOURCE[0]:-${(%):-%x}}")"
+if "${BIN_DIR}/hermit" noop > /dev/null; then
+  eval "$("${BIN_DIR}/hermit" activate "${BIN_DIR}/..")"
+
+  if [ -n "${BASH-}" ] || [ -n "${ZSH_VERSION-}" ]; then
+      hash -r 2>/dev/null
+    fi
+
+    echo "Hermit environment $("${HERMIT_ENV}"/bin/hermit env HERMIT_ENV) activated"
+fi

go-runtime/scaffolding/bin/go

@@ -0,0 +1 @@
+.go-1.21.3.pkg

go-runtime/scaffolding/bin/gofmt

@@ -0,0 +1 @@
+.go-1.21.3.pkg

go-runtime/scaffolding/bin/hermit

@@ -0,0 +1,43 @@
+#!/bin/bash
+#
+# THIS FILE IS GENERATED; DO NOT MODIFY
+
+set -eo pipefail
+
+export HERMIT_USER_HOME=~
+
+if [ -z "${HERMIT_STATE_DIR}" ]; then
+  case "$(uname -s)" in
+  Darwin)
+    export HERMIT_STATE_DIR="${HERMIT_USER_HOME}/Library/Caches/hermit"
+    ;;
+  Linux)
+    export HERMIT_STATE_DIR="${XDG_CACHE_HOME:-${HERMIT_USER_HOME}/.cache}/hermit"
+    ;;
+  esac
+fi
+
+export HERMIT_DIST_URL="${HERMIT_DIST_URL:-https://github.com/cashapp/hermit/releases/download/stable}"
+HERMIT_CHANNEL="$(basename "${HERMIT_DIST_URL}")"
+export HERMIT_CHANNEL
+export HERMIT_EXE=${HERMIT_EXE:-${HERMIT_STATE_DIR}/pkg/hermit@${HERMIT_CHANNEL}/hermit}
+
+if [ ! -x "${HERMIT_EXE}" ]; then
+  echo "Bootstrapping ${HERMIT_EXE} from ${HERMIT_DIST_URL}" 1>&2
+  INSTALL_SCRIPT="$(mktemp)"
+  # This value must match that of the install script
+  INSTALL_SCRIPT_SHA256="180e997dd837f839a3072a5e2f558619b6d12555cd5452d3ab19d87720704e38"
+  if [ "${INSTALL_SCRIPT_SHA256}" = "BYPASS" ]; then
+    curl -fsSL "${HERMIT_DIST_URL}/install.sh" -o "${INSTALL_SCRIPT}"
+  else
+    # Install script is versioned by its sha256sum value
+    curl -fsSL "${HERMIT_DIST_URL}/install-${INSTALL_SCRIPT_SHA256}.sh" -o "${INSTALL_SCRIPT}"
+    # Verify install script's sha256sum
+    openssl dgst -sha256 "${INSTALL_SCRIPT}" | \
+      awk -v EXPECTED="$INSTALL_SCRIPT_SHA256" \
+      '$2!=EXPECTED {print "Install script sha256 " $2 " does not match " EXPECTED; exit 1}'
+  fi
+  /bin/bash "${INSTALL_SCRIPT}" 1>&2
+fi
+
+exec "${HERMIT_EXE}" --level=fatal exec "$0" -- "$@"

go-runtime/scaffolding/ftl.toml

@@ -0,0 +1,2 @@
+module = "{{ .Name | lower }}"
+language = "go"

go-runtime/scaffolding/go.mod

@@ -0,0 +1,5 @@
+module {{ .GoModule }}
+
+go 1.21.0
+
+require github.com/TBD54566975/ftl latest

go-runtime/scaffolding/{{ .Name | lower }}.go

@@ -0,0 +1,18 @@
+//ftl:module {{ .Name | lower }}
+package {{ .Name | lower }}
+
+import (
+	"context"
+	_ "github.com/TBD54566975/ftl/go-runtime/sdk" // Import the FTL SDK.
+)
+
+type {{ .Name | camel }}Request struct {
+}
+
+type {{ .Name | camel }}Response struct {
+}
+
+//ftl:verb
+func {{ .Name | camel }}(ctx context.Context, req {{ .Name | camel }}Request) ({{ .Name | camel }}Response, error) {
+	return {{ .Name | camel }}Response{}, nil
+}

go.mod

@@ -44,6 +44,7 @@ require (
 	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
 	github.com/jackc/puddle/v2 v2.2.0 // indirect
 	github.com/pelletier/go-toml v1.9.5 // indirect
+	github.com/stretchr/objx v0.2.0 // indirect
 	github.com/swaggest/refl v1.2.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlpmetric v0.42.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.19.0 // indirect