fix: address all High and Medium follow-up review items

.github/workflows/ci.yaml

@@ -3,8 +3,13 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  check:
-    runs-on: ubuntu-latest
+  unit-tests:
+    name: unit (${{ matrix.os }})
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -14,10 +19,24 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: 1.21
+          go-version: '1.24'
 
       - name: Unit tests
-        run: go test ./...
+        run: go test -race ./...
+
+  integration:
+    name: integration + goreleaser
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version: '1.24'
 
       - name: Integration tests
         run: ./test.sh

.github/workflows/release.yaml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: 1.21
+          go-version: '1.24'
 
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v7

.goreleaser.yaml

@@ -4,6 +4,10 @@ builds:
   - main: ./cmd/terraform-demux
     env:
       - CGO_ENABLED=0
+    # Inject the release tag into main.version so `terraform-demux -version`
+    # reports something other than the package default v0.0.1+dev.
+    ldflags:
+      - -s -w -X main.version=v{{.Version}}
     goos:
       - linux
       - windows

README.md

@@ -23,7 +23,7 @@ A seamless launcher for Terraform.
 
 Simply navigate to any folder that contains Terraform configuration and run `terraform` as you usually would. `terraform-demux` will attempt to locate the appropriate [version constraint](https://www.terraform.io/docs/language/expressions/version-constraints.html) by searching in the current working directory and recursively through parent directories. If `terraform-demux` cannot determine a constraint, it will default to the latest possible version.
 
-### Architecture Compatability
+### Architecture Compatibility
 
 `terraform-demux` supports a native `arm64` build that can also run `amd64` versions of `terraform` by specifying the `TF_DEMUX_ARCH` environment variable. This might be necessary for `terraform` workspaces that need older `terraform` versions that do not have `arm64` builds, or use older providers that do not have `arm64` builds.
 
@@ -39,11 +39,11 @@ We highly encourage leveraging native Terraform refactoring blocks whenever feas
 
 Usage Details
 
-* For Terraform 1.1.0 and above: We recomment utilizing Terraform [moved](https://developer.hashicorp.com/terraform/language/modules/develop/refactoring) block instead `terraform state mv` command.
+* For Terraform 1.1.0 and above: we recommend using Terraform's [moved](https://developer.hashicorp.com/terraform/language/modules/develop/refactoring) block instead of the `terraform state mv` command.
 
-* For Terraform 1.5.0 and above: We recomment utilizing Terraform [import](https://developer.hashicorp.com/terraform/language/import) block instead `terraform import` command.
+* For Terraform 1.5.0 and above: we recommend using Terraform's [import](https://developer.hashicorp.com/terraform/language/import) block instead of the `terraform import` command.
 
-* For Terraform 1.7.0 and above:  We recomment utilizing Terraform [removed](https://developer.hashicorp.com/terraform/language/resources/syntax) block instead `terraform state rm` command.
+* For Terraform 1.7.0 and above: we recommend using Terraform's [removed](https://developer.hashicorp.com/terraform/language/resources/syntax) block instead of the `terraform state rm` command.
 
 However, if necessary, you can still utilize the Terraform CLI to manipulate states. Before proceeding, ensure to set the environment variable `TF_DEMUX_ALLOW_STATE_COMMANDS=true` to confirm your intent.
 
@@ -53,4 +53,6 @@ Setting the `TF_DEMUX_LOG` environment variable to any non-empty value will caus
 
 ## Cache Directory
 
-`terraform-demux` keeps a cache of Hashicorp's releases index and downloaded Terraform binaries in the directory returned by [os.UserCacheDir](https://golang.org/pkg/os/#UserCacheDir), under `terraform-demux/` (e.g. `~/Library/Caches/terraform-demux/` on MacOS).
+`terraform-demux` keeps a cache of HashiCorp's releases index and downloaded Terraform binaries in the directory returned by [os.UserCacheDir](https://golang.org/pkg/os/#UserCacheDir), under `terraform-demux/` (e.g. `~/Library/Caches/terraform-demux/` on macOS).
+
+Setting `TF_DEMUX_CACHE_HOME` overrides this location. This is useful for tests, sandboxes, and CI runners where you don't want the wrapper to touch the user's real cache (note that `XDG_CACHE_HOME` is ignored by `os.UserCacheDir` on macOS).

cmd/terraform-demux/main.go

@@ -1,29 +1,18 @@
 package main
 
 import (
-	"bytes"
 	"log"
 	"os"
 	"runtime"
 
 	"github.com/etsy/terraform-demux/internal/wrapper"
 )
 
-var (
-	version = "v0.0.1+dev"
-)
+var version = "v0.0.1+dev"
 
 func main() {
-	// When TF_DEMUX_LOG is unset, hold log output in a buffer so we can
-	// replay it on stderr if something goes wrong. Otherwise the user only
-	// sees the final error message and not the trace that led to it.
-	var logBuf bytes.Buffer
-	verboseLogging := os.Getenv("TF_DEMUX_LOG") != ""
-	if verboseLogging {
-		log.SetOutput(os.Stderr)
-	} else {
-		log.SetOutput(&logBuf)
-	}
+	verbose := os.Getenv("TF_DEMUX_LOG") != ""
+	flushLog := wrapper.SetupLogging(verbose, os.Stderr)
 
 	arch := os.Getenv("TF_DEMUX_ARCH")
 	if arch == "" {
@@ -34,9 +23,7 @@ func main() {
 
 	exitCode, err := wrapper.RunTerraform(os.Args[1:], arch)
 	if err != nil {
-		if !verboseLogging {
-			os.Stderr.Write(logBuf.Bytes())
-		}
+		flushLog()
 		log.SetOutput(os.Stderr)
 		log.Fatal("error: ", err)
 	}

go.mod

@@ -1,9 +1,10 @@
 module github.com/etsy/terraform-demux
 
-go 1.21
+go 1.24.0
 
 require (
 	github.com/Masterminds/semver/v3 v3.2.1
+	github.com/gofrs/flock v0.13.0
 	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79
 	github.com/hashicorp/terraform-config-inspect v0.0.0-20231204233900-a34142ec2a72
 	github.com/natefinch/atomic v1.0.1
@@ -18,6 +19,8 @@ require (
 	github.com/hashicorp/hcl/v2 v2.0.0 // indirect
 	github.com/mitchellh/go-wordwrap v1.0.0 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
+	github.com/rogpeppe/go-internal v1.14.1 // indirect
 	github.com/zclconf/go-cty v1.1.0 // indirect
+	golang.org/x/sys v0.37.0 // indirect
 	golang.org/x/text v0.3.8 // indirect
 )

go.sum

@@ -10,6 +10,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-test/deep v1.0.3 h1:ZrJSEWsXzPOxaZnFteGEfooLba+ju3FYIbOrS+rQd68=
 github.com/go-test/deep v1.0.3/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/gofrs/flock v0.13.0 h1:95JolYOvGMqeH31+FC7D2+uULf6mG61mEZ/A8dRYMzw=
+github.com/gofrs/flock v0.13.0/go.mod h1:jxeyy9R1auM5S6JYDBhDt+E2TCo7DkratH4Pgi8P+Z0=
 github.com/golang/protobuf v1.1.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/btree v1.0.1 h1:gK4Kx5IaGY9CD5sPJ36FHiBJ6ZXl0kilRiiCj+jdYp4=
 github.com/google/btree v1.0.1/go.mod h1:xXMiIv4Fb/0kKde4SpL7qlzvu5cMJDRkFDxJfI9uaxA=
@@ -24,8 +26,9 @@ github.com/hashicorp/hcl/v2 v2.0.0 h1:efQznTz+ydmQXq3BOnRa3AXzvCeTq1P4dKj/z5GLlY
 github.com/hashicorp/hcl/v2 v2.0.0/go.mod h1:oVVDG71tEinNGYCxinCYadcmKU9bglqW9pV3txagJ90=
 github.com/hashicorp/terraform-config-inspect v0.0.0-20231204233900-a34142ec2a72 h1:nZ5gGjbe5o7XUu1d7j+Y5Ztcxlp+yaumTKH9i0D3wlg=
 github.com/hashicorp/terraform-config-inspect v0.0.0-20231204233900-a34142ec2a72/go.mod h1:l8HcFPm9cQh6Q0KSWoYPiePqMvRFenybP1CH2MjKdlg=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
@@ -39,11 +42,16 @@ github.com/natefinch/atomic v1.0.1 h1:ZPYKxkqQOx3KZ+RsbnP/YsgvxWQPGxjC0oBt2AhwV0
 github.com/natefinch/atomic v1.0.1/go.mod h1:N/D/ELrljoqDyT3rZrsUmtsuzvHkeB/wWjHV22AZRbM=
 github.com/peterbourgon/diskv v2.0.1+incompatible h1:UBdAOUP5p4RWqPBg048CAvpKN+vxiaj6gdUUzhl4XmI=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
+github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
 github.com/spf13/pflag v1.0.2/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/vmihailenco/msgpack v3.3.3+incompatible/go.mod h1:fy3FlTQTDXWkZ7Bh6AcGMlsjHatGryHQYUTf1ShIgkk=
 github.com/zclconf/go-cty v1.1.0 h1:uJwc9HiBOCpoKIObTQaLR+tsEXx1HBHnOsOOpcdhZgw=
 github.com/zclconf/go-cty v1.1.0/go.mod h1:xnAOWiHeOqg2nWS62VtQ7pbOu17FtxJNW8RLEih+O3s=
@@ -55,10 +63,14 @@ golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190502175342-a43fa875dd82/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=