test: demonstrate issue with signal handling in golang with pact_ffi

go/Makefile

@@ -0,0 +1,42 @@
+SKIP_SIGNAL_HANDLERS?=false
+TEST_COUNT?=50
+RACE=-race
+CGO_ENABLED=1
+ifeq ($(CGO_ENABLED),0)
+	SKIP_RACE=true
+endif
+ifeq ($(SKIP_RACE),true)
+	RACE=
+endif
+# export PACT_PROVIDER_DIR?=./pacts_plugin_protobuf
+
+ifeq ($(PACT_PROVIDER),protobuf)
+	export PACT_PROVIDER_DIR=./pacts_plugin_protobuf
+else ifeq ($(PACT_PROVIDER),csv)
+	export PACT_PROVIDER_DIR=./pacts_plugin_csv
+else ifeq ($(PACT_PROVIDER),avro)
+	export PACT_PROVIDER_DIR=./pacts_plugin_avro
+else ifeq ($(PACT_PROVIDER),message)
+	export PACT_PROVIDER_DIR=./pacts_plugin_message
+else
+	export PACT_PROVIDER_DIR=./pacts_http
+endif
+
+run:
+	go run pact/go/native/native
+
+test:
+	go test -v $(SKIP_RACE) -count $(TEST_COUNT) pact/go/native/native
+
+test_protobuf:
+	make test PACT_PROVIDER=protobuf
+test_csv:
+	make test PACT_PROVIDER=csv
+test_avro:
+	make test PACT_PROVIDER=avro
+test_go:
+	make test PACT_PROVIDER=go
+test_message:
+	make test
+test_http:
+	make test

go/go.mod

@@ -0,0 +1,8 @@
+module pact/go/native
+
+go 1.22.2
+
+require (
+	github.com/ebitengine/purego v0.7.1
+	golang.org/x/sys v0.21.0
+)

go/go.sum

@@ -0,0 +1,4 @@
+github.com/ebitengine/purego v0.7.1 h1:6/55d26lG3o9VCZX8lping+bZcmShseiqlh2bnUDiPA=
+github.com/ebitengine/purego v0.7.1/go.mod h1:ah1In8AOtksoNK6yk5z1HTJeUkC1Ez4Wk2idgGslMwQ=
+golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
+golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

go/native/README.md

@@ -0,0 +1,97 @@
+# Go Interop with Rust Issue
+
+This is an example which shows a Rust project which has been compiled as a shared library, and is called from multiple languages including Go.
+
+The rust project, may call out to external executables (called plugins) which can be written in any language.
+
+This is currently causing issues with occasional segfaults in Linux / MacOS.
+
+## Rust shared library
+
+The rust shared library is currently built for the following platforms.
+
+- x86_64-unknown-linux-gnu
+- aarch64-unknown-linux-gnu
+- x86_64-unknown-linux-musl
+- aarch64-unknown-linux-musl
+- x86_64-apple-darwin
+- aarch64-apple-darwin
+- x86_64-pc-windows-msvc
+- aarch64-pc-windows-msvc
+
+## Calling languages
+
+It is called from various languages, including but not limited to:
+
+- Golang (via cgo)
+- JS (via node-napi)
+- PHP (via FFI)
+- Python (via cffi)
+
+## Plugins, controlled by the rust shared library
+
+The shared library, may load plugins which are written in any language, and may call out to external executables which are written in any language.
+
+The following languages are currently being used as plugins:
+
+- Golang
+  - Built with GoReleaser for the following platforms:
+    - linux/amd64
+    - linux/arm64
+    - darwin/amd64
+    - darwin/arm64
+    - windows/amd64
+    - windows/arm64
+- Rust
+  - Built with cross / cargo
+  - For linux, musl static builds are used to work on glibc & musl systems
+    - x86_64-unknown-linux-musl
+    - aarch64-unknown-linux-musl
+    - x86_64-apple-darwin
+    - aarch64-apple-darwin
+    - x86_64-pc-windows-msvc
+    - aarch64-pc-windows-msvc
+- Java
+  - Requires user to have openjdk 17 installed
+
+## Issues
+
+### Issue 1 - Segfaults on Linux / MacOS
+
+```
+signal 17 received but handler not on signal stack
+mp.gsignal stack [0x400006e000 0x4000076000], mp.g0 stack [0xffff4320e810 0xffff43a0e410], sp=0x40000e3608
+fatal error: non-Go code set up signal handler without SA_ONSTACK flag
+```
+
+Fixed by workaround in following PR
+
+- https://github.com/wailsapp/wails/pull/2152/files#diff-d4a0fa73df7b0ab971e550f95249e358b634836e925ace96f7400480916ac09e
+
+> Sets up a new signal handler in C that overrides the current one (in C) so that SA_ONSTACK is used.
+
+See golang docs for os/signal 
+
+https://pkg.go.dev/os/signal#hdr-Go_programs_that_use_cgo_or_SWIG
+
+> If the non-Go code installs any signal handlers, it must use the SA_ONSTACK flag with sigaction. Failing to do so is likely to cause the program to crash if the signal is received. Go programs routinely run with a limited stack, and therefore set up an alternate signal stack.
+
+#### Additional Problems
+
+1. Does not fix Alpine linux
+2. Fix does not with CGO_ENABLED=0 using https://github.com/ebitengine/purego, as it requires C code to be injected.
+   1. Probably fix needs to be applied to fakego in purego
+
+## Testing
+
+- Use of CGO or ebitengine/purego is controlled by `CGO_ENABLED=1` for `cgo` and `CGO_ENABLED=0` for `purego`
+- Fix can be removed by settings `SKIP_SIGNAL_HANDLERS=true`
+
+### Issue 2 - Windows plugin executables are not shutdown properly
+
+```
+*** Test I/O incomplete 1m0s after exiting.
+exec: WaitDelay expired before I/O complete
+```
+
+The windows executable is shutdown externally via taskkill or the task manager, will exit the plugin correctly and the test will pass.

go/native/lib.go

@@ -0,0 +1,38 @@
+//go:build cgo
+// +build cgo
+
+// Package native contains the c bindings into the Pact Reference types.
+package main
+
+/*
+#cgo darwin,arm64 LDFLAGS: -L/tmp -L/usr/local/lib -Wl,-rpath -Wl,/tmp -Wl,-rpath -Wl,/usr/local/lib -lpact_ffi
+#cgo darwin,amd64 LDFLAGS: -L/tmp -L/usr/local/lib -Wl,-rpath -Wl,/tmp -Wl,-rpath -Wl,/usr/local/lib -lpact_ffi
+#cgo windows,amd64 LDFLAGS: -lpact_ffi
+#cgo linux,amd64 LDFLAGS: -L/tmp -L/opt/pact/lib -L/usr/local/lib -Wl,-rpath -Wl,/opt/pact/lib -Wl,-rpath -Wl,/tmp -Wl,-rpath -Wl,/usr/local/lib -lpact_ffi
+#cgo linux,arm64 LDFLAGS: -L/tmp -L/opt/pact/lib -L/usr/local/lib -Wl,-rpath -Wl,/opt/pact/lib -Wl,-rpath -Wl,/tmp -Wl,-rpath -Wl,/usr/local/lib -lpact_ffi
+#include "pact.h"
+*/
+import "C"
+import (
+	"fmt"
+	"os"
+)
+
+func plugin_provider() int {
+	verifier := C.pactffi_verifier_new()
+	// C.pactffi_log_to_stdout(0)
+	C.pactffi_verifier_set_provider_info(verifier, C.CString("p1"), C.CString("http"), C.CString("localhost"), 8000, C.CString("/"))
+	// C.pactffi_verifier_add_provider_transport(verifier, C.CString("http"), 8000, C.CString("/"), C.CString("http"))
+	// C.pactffi_verifier_add_provider_transport(verifier, C.CString("protobuf"), 37757, C.CString("/"), C.CString("tcp"))
+
+	C.pactffi_verifier_add_directory_source(verifier, C.CString(os.Getenv("PACT_PROVIDER_DIR")))
+	InstallSignalHandlers()
+	defer C.pactffi_verifier_shutdown(verifier)
+	result := C.pactffi_verifier_execute(verifier)
+	if result != 0 {
+		fmt.Printf("Result is not 0: %d", result)
+	} else {
+		fmt.Print("Result success")
+	}
+	return int(result)
+}