go1.20+: Refuse to work if cgo is enabled

On go1.20+ it is no longer possible to directly copy a cgo-enabled
library into a docker container. For this reason, this commit adds a
flag to commands that automatically make them fail with an appropriate
message if cgo is enabled.

.github/workflows/test.yaml

@@ -36,7 +36,7 @@ jobs:
           go test ./...
       - name: Build executable
         run: |
-          go build -o wdcli ./cmd/wdcli
+          CGO_ENABLED=0 go build -o wdcli ./cmd/wdcli
       - name: Upload Release
         uses: softprops/action-gh-release@v1
         if: startsWith(github.ref, 'refs/tags/')

Makefile

@@ -4,7 +4,7 @@ all: wdcli
 
 wdcli:
 	go generate ./internal/dis/component/control/static/
-	go build -o ./wdcli ./cmd/wdcli
+	CGO_ENABLED=0 go build -o ./wdcli ./cmd/wdcli
 
 deps: internal/dis/component/server/assets/node_modules
 

README.md

@@ -58,7 +58,7 @@ To bootstrap a new distillery instance, the `wdcli bootstrap` command can be use
 First copy the executable onto the server, using a command similar as:
 
 ```bash
-GOOS=linux GOARCH=amd64 go build -o wdcli ./cmd/wdcli && scp ./wdcli distillery.example.com:
+CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o wdcli ./cmd/wdcli && scp ./wdcli distillery.example.com:
 ```
 
 Next, access the server and run the `bootstrap` command:

cmd/system_update.go

@@ -31,6 +31,7 @@ func (systemupdate) Description() wisski_distillery.Description {
 	return wisski_distillery.Description{
 		Requirements: cli.Requirements{
 			NeedsDistillery: true,
+			FailOnCgo:       true,
 		},
 		ParserConfig: parser.Config{
 			IncludeUnknown: true,

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/pquerna/otp v1.4.0
 	github.com/rs/zerolog v1.29.0
 	github.com/tkw1536/goprogram v0.3.5
-	github.com/tkw1536/pkglib v0.0.0-20230409110642-5f57240e294b
+	github.com/tkw1536/pkglib v0.0.0-20230427085354-69b5e047c325
 	github.com/yuin/goldmark v1.5.4
 	github.com/yuin/goldmark-meta v1.1.0
 	golang.org/x/crypto v0.8.0

go.sum

@@ -117,6 +117,8 @@ github.com/tkw1536/goprogram v0.3.5 h1:S0axKo3R/vGa4zhYqYDKAZEPhAfwUSSeMtVwnAu4s
 github.com/tkw1536/goprogram v0.3.5/go.mod h1:pYr4dMHOSVurbPQ4KTR0ett8XWNISbsRS6zlh9Nsxa8=
 github.com/tkw1536/pkglib v0.0.0-20230409110642-5f57240e294b h1:qeoY+XHCDx1fubOJkLuMSdz4xNWtgeLpxPfxBiEIj4c=
 github.com/tkw1536/pkglib v0.0.0-20230409110642-5f57240e294b/go.mod h1:0A1B9Cc5+yJXR3eeB14CqD4dFSbEjjWRo5Pr9M3XYuI=
+github.com/tkw1536/pkglib v0.0.0-20230427085354-69b5e047c325 h1:A1XZyL73L+FI/r3P7OLnibAFDlCV0Q8dTU7bwFfAYvo=
+github.com/tkw1536/pkglib v0.0.0-20230427085354-69b5e047c325/go.mod h1:0A1B9Cc5+yJXR3eeB14CqD4dFSbEjjWRo5Pr9M3XYuI=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
 github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb h1:zGWFAtiMcyryUHoUjUJX0/lt1H2+i2Ka2n+D3DImSNo=
 github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=

internal/cli/requirements.go

@@ -9,6 +9,9 @@ import (
 type Requirements struct {
 	// Do we need an installed distillery?
 	NeedsDistillery bool
+
+	// Automatically fail when cgo is enabled?
+	FailOnCgo bool
 }
 
 // AllowsFlag checks if the provided flag may be passed to fullfill this requirement

internal/dis/init.go

@@ -7,6 +7,7 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/config"
 	"github.com/FAU-CDI/wisski-distillery/internal/dis/component"
 	"github.com/tkw1536/goprogram/exit"
+	"github.com/tkw1536/pkglib/cgo"
 )
 
 var errNoConfigFile = exit.Error{
@@ -19,8 +20,20 @@ var errOpenConfig = exit.Error{
 	Message:  "error loading configuration file: %q",
 }
 
+// An error to be returned when cgo is enabled unexpectedly.
+var CGoEnabled = exit.Error{
+	ExitCode: exit.ExitGeneralArguments,
+	Message:  "this functionality is only available when cgo support is disabled. Set `CGO_ENABLED=0' at build time and try again",
+}
+
 // NewDistillery creates a new distillery from the provided flags
 func NewDistillery(params cli.Params, flags cli.Flags, req cli.Requirements) (dis *Distillery, err error) {
+	// check cgo support to prevent weird error messages
+	// this has to happen either when we are inside docker, or when explicity requested by the command.
+	if cgo.Enabled && (flags.InternalInDocker || req.FailOnCgo) {
+		return nil, CGoEnabled
+	}
+
 	dis = new(Distillery)
 	dis.Still.Upstream = component.Upstream{
 		SQL:         component.HostPort{Host: "127.0.0.1", Port: 3306},

program.go

@@ -12,6 +12,7 @@ import (
 	"github.com/rs/zerolog"
 	"github.com/tkw1536/goprogram"
 	"github.com/tkw1536/goprogram/exit"
+	"github.com/tkw1536/pkglib/cgo"
 )
 
 // these define the ggman-specific program types
@@ -59,12 +60,7 @@ var errUserIsNotRoot = exit.Error{
 	Message:  "this command has to be executed as root. the current user is not root",
 }
 
-// an error when cgo is enabled
+const warnCGoEnabled = "Warning: This executable has been built with cgo enabled. This means certain commands may not work. \n"
-var errCGoEnabled = exit.Error{
-	ExitCode: exit.ExitGeneralArguments,
-	Message:  "this command has to be executed as root. the current user is not root",
-}
-
 const warnNoDeployWdcli = "Warning: Not using %q executable at %q. This might leave the distillery in an inconsistent state. \n"
 
 func NewProgram() Program {
@@ -76,6 +72,11 @@ func NewProgram() Program {
 				return errUserIsNotRoot
 			}
 
+			// warn about cgo!
+			if cgo.Enabled {
+				context.Printf(warnCGoEnabled)
+			}
+
 			// when not running inside docker and we need a distillery
 			// then we should warn if we are not using the distillery executable.
 			if dis := context.Environment; !context.Args.Flags.InternalInDocker && context.Description.Requirements.NeedsDistillery && !dis.Config.Paths.UsingDistilleryExecutable() {