Use Existing Terraform CLI binary, otherwise download latest (#124)

Check for a Terraform binary first, then fall back to downloading the latest version; also support set exact version to download via new `tf-version` command flag.

go.mod

@@ -23,8 +23,10 @@ require (
 	github.com/fatih/color v1.7.0 // indirect
 	github.com/google/uuid v1.1.2 // indirect
 	github.com/hashicorp/errwrap v1.0.0 // indirect
+	github.com/hashicorp/go-checkpoint v0.5.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
+	github.com/hashicorp/go-uuid v1.0.0 // indirect
 	github.com/huandu/xstrings v1.3.2 // indirect
 	github.com/imdario/mergo v0.3.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect

go.sum

@@ -50,13 +50,15 @@ github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
 github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
+github.com/hashicorp/go-checkpoint v0.5.0 h1:MFYpPZCnQqQTE18jFwSII6eUQrD/oxMFp3mlgcqk5mU=
 github.com/hashicorp/go-checkpoint v0.5.0/go.mod h1:7nfLNL10NsxqO4iWuW6tWW0HjZuDrwkBuEQsVcpCOgg=
 github.com/hashicorp/go-cleanhttp v0.5.0/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
 github.com/hashicorp/go-cleanhttp v0.5.2 h1:035FKYIWjmULyFRBKPs8TBQoi0x6d9G4xc9neXJWAZQ=
 github.com/hashicorp/go-cleanhttp v0.5.2/go.mod h1:kO/YDlP8L1346E6Sodw+PrpBSV4/SoxCXGY6BqNFT48=
 github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
 github.com/hashicorp/go-multierror v1.1.1 h1:H5DkEtf6CXdFp0N0Em5UCwQpXMWke8IA0+lD48awMYo=
 github.com/hashicorp/go-multierror v1.1.1/go.mod h1:iw975J/qwKPdAO1clOe2L8331t/9/fmwbPZ6JB6eMoM=
+github.com/hashicorp/go-uuid v1.0.0 h1:RS8zrF7PhGwyNPOtxSClXXj9HA8feRnJzgnI1RJCSnM=
 github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/go-version v1.3.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
 github.com/hashicorp/go-version v1.4.0 h1:aAQzgqIrRKRa7w75CKpbBxYsmUoPjzVm1W59ca1L0J4=

internal/cmd/generate.go

@@ -11,6 +11,7 @@ type generateCmd struct {
 	commonCmd
 
 	flagLegacySidebar bool
+	tfVersion         string
 }
 
 func (cmd *generateCmd) Synopsis() string {
@@ -24,6 +25,7 @@ func (cmd *generateCmd) Help() string {
 func (cmd *generateCmd) Flags() *flag.FlagSet {
 	fs := flag.NewFlagSet("generate", flag.ExitOnError)
 	fs.BoolVar(&cmd.flagLegacySidebar, "legacy-sidebar", false, "generate the legacy .erb sidebar file")
+	fs.StringVar(&cmd.tfVersion, "tf-version", "", "terraform binary version to download")
 	return fs
 }
 
@@ -39,7 +41,7 @@ func (cmd *generateCmd) Run(args []string) int {
 }
 
 func (cmd *generateCmd) runInternal() error {
-	err := provider.Generate(cmd.ui, cmd.flagLegacySidebar)
+	err := provider.Generate(cmd.ui, cmd.flagLegacySidebar, cmd.tfVersion)
 	if err != nil {
 		return fmt.Errorf("unable to generate website: %w", err)
 	}

internal/provider/generate.go

@@ -11,8 +11,12 @@ import (
 	"strings"
 
 	"github.com/hashicorp/go-version"
+	install "github.com/hashicorp/hc-install"
+	"github.com/hashicorp/hc-install/checkpoint"
+	"github.com/hashicorp/hc-install/fs"
 	"github.com/hashicorp/hc-install/product"
 	"github.com/hashicorp/hc-install/releases"
+	"github.com/hashicorp/hc-install/src"
 	"github.com/hashicorp/terraform-exec/tfexec"
 	tfjson "github.com/hashicorp/terraform-json"
 	"github.com/mitchellh/cli"
@@ -74,6 +78,7 @@ var (
 
 type generator struct {
 	legacySidebar bool
+	tfVersion     string
 
 	ui cli.Ui
 }
@@ -86,9 +91,10 @@ func (g *generator) warnf(format string, a ...interface{}) {
 	g.ui.Warn(fmt.Sprintf(format, a...))
 }
 
-func Generate(ui cli.Ui, legacySidebar bool) error {
+func Generate(ui cli.Ui, legacySidebar bool, tfVersion string) error {
 	g := &generator{
 		legacySidebar: legacySidebar,
+		tfVersion:     tfVersion,
 
 		ui: ui,
 	}
@@ -498,13 +504,31 @@ provider %[1]q {
 		return nil, err
 	}
 
-	g.infof("getting Terraform binary")
-	installer := &releases.ExactVersion{
-		Product:    product.Terraform,
-		Version:    version.Must(version.NewVersion("1.0.5")),
-		InstallDir: tmpDir,
+	i := install.NewInstaller()
+	sources := []src.Source{}
+	if g.tfVersion != "" {
+		g.infof("downloading Terraform CLI binary version from releases.hashicorp.com: %s", g.tfVersion)
+		sources = []src.Source{
+			&releases.ExactVersion{
+				Product:    product.Terraform,
+				Version:    version.Must(version.NewVersion(g.tfVersion)),
+				InstallDir: tmpDir,
+			},
+		}
+	} else {
+		g.infof("using Terraform CLI binary from PATH if available, otherwise downloading latest Terraform CLI binary")
+		sources = []src.Source{
+			&fs.AnyVersion{
+				Product: &product.Terraform,
+			},
+			&checkpoint.LatestVersion{
+				InstallDir: tmpDir,
+				Product:    product.Terraform,
+			},
+		}
 	}
-	tfBin, err := installer.Install(context.Background())
+
+	tfBin, err := i.Ensure(context.Background(), sources)
 	if err != nil {
 		return nil, err
 	}