internal: reintroduce legacy appengine build constraints (#3838)

internal/channelz/types_linux.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2018 gRPC authors.

internal/channelz/types_nonlinux.go

@@ -37,6 +37,6 @@ type SocketOptionData struct {
 // Windows OS doesn't support Socket Option
 func (s *SocketOptionData) Getsockopt(fd uintptr) {
 	once.Do(func() {
-		logger.Warning("Channelz: socket options are not supported on non-linux os.")
+		logger.Warning("Channelz: socket options are not supported on non-linux os and appengine.")
 	})
 }

internal/channelz/util_linux.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build linux,!appengine
 
 /*
  *

internal/channelz/util_test.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build linux,!appengine
 
 /*
  *

internal/credentials/spiffe.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2020 gRPC authors.

internal/credentials/syscallconn.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2018 gRPC authors.

internal/credentials/syscallconn_test.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2018 gRPC authors.

internal/profiling/buffer/buffer.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2019 gRPC authors.

internal/profiling/buffer/buffer_appengine.go

@@ -0,0 +1,43 @@
+// +build appengine
+
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package buffer
+
+// CircularBuffer is a no-op implementation for appengine builds.
+//
+// Appengine does not support stats because of lack of the support for unsafe
+// pointers, which are necessary to efficiently store and retrieve things into
+// and from a circular buffer. As a result, Push does not do anything and Drain
+// returns an empty slice.
+type CircularBuffer struct{}
+
+// NewCircularBuffer returns a no-op for appengine builds.
+func NewCircularBuffer(size uint32) (*CircularBuffer, error) {
+	return nil, nil
+}
+
+// Push returns a no-op for appengine builds.
+func (cb *CircularBuffer) Push(x interface{}) {
+}
+
+// Drain returns a no-op for appengine builds.
+func (cb *CircularBuffer) Drain() []interface{} {
+	return nil
+}

internal/profiling/buffer/buffer_test.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2019 gRPC authors.

internal/syscall/syscall_linux.go

@@ -1,3 +1,5 @@
+// +build !appengine
+
 /*
  *
  * Copyright 2018 gRPC authors.

internal/syscall/syscall_nonlinux.go

@@ -35,40 +35,40 @@ var logger = grpclog.Component("core")
 
 func log() {
 	once.Do(func() {
-		logger.Info("CPU time info is unavailable on non-linux environment.")
+		logger.Info("CPU time info is unavailable on non-linux or appengine environment.")
 	})
 }
 
 // GetCPUTime returns the how much CPU time has passed since the start of this process.
-// It always returns 0 under non-linux environment.
+// It always returns 0 under non-linux or appengine environment.
 func GetCPUTime() int64 {
 	log()
 	return 0
 }
 
-// Rusage is an empty struct under non-linux environment.
+// Rusage is an empty struct under non-linux or appengine environment.
 type Rusage struct{}
 
-// GetRusage is a no-op function under non-linux environment.
+// GetRusage is a no-op function under non-linux or appengine environment.
 func GetRusage() (rusage *Rusage) {
 	log()
 	return nil
 }
 
 // CPUTimeDiff returns the differences of user CPU time and system CPU time used
-// between two Rusage structs. It a no-op function for non-linux environment.
+// between two Rusage structs. It a no-op function for non-linux or appengine environment.
 func CPUTimeDiff(first *Rusage, latest *Rusage) (float64, float64) {
 	log()
 	return 0, 0
 }
 
-// SetTCPUserTimeout is a no-op function under non-linux environments
+// SetTCPUserTimeout is a no-op function under non-linux or appengine environments
 func SetTCPUserTimeout(conn net.Conn, timeout time.Duration) error {
 	log()
 	return nil
 }
 
-// GetTCPUserTimeout is a no-op function under non-linux environments
+// GetTCPUserTimeout is a no-op function under non-linux or appengine environments
 // a negative return value indicates the operation is not supported
 func GetTCPUserTimeout(conn net.Conn) (int, error) {
 	log()

interop/grpclb_fallback/client.go

@@ -1,4 +1,4 @@
-// +build linux
+// +build linux,!appengine
 
 /*
  *

test/go_vet/vet.go

@@ -0,0 +1,53 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// vet checks whether files that are supposed to be built on appengine running
+// Go 1.10 or earlier import an unsupported package (e.g. "unsafe", "syscall").
+package main
+
+import (
+	"fmt"
+	"go/build"
+	"os"
+)
+
+func main() {
+	fail := false
+	b := build.Default
+	b.BuildTags = []string{"appengine", "appenginevm"}
+	argsWithoutProg := os.Args[1:]
+	for _, dir := range argsWithoutProg {
+		p, err := b.Import(".", dir, 0)
+		if _, ok := err.(*build.NoGoError); ok {
+			continue
+		} else if err != nil {
+			fmt.Printf("build.Import failed due to %v\n", err)
+			fail = true
+			continue
+		}
+		for _, pkg := range p.Imports {
+			if pkg == "syscall" || pkg == "unsafe" {
+				fmt.Printf("Package %s/%s importing %s package without appengine build tag is NOT ALLOWED!\n", p.Dir, p.Name, pkg)
+				fail = true
+			}
+		}
+	}
+	if fail {
+		os.Exit(1)
+	}
+}

vet.sh

@@ -92,6 +92,10 @@ not git grep "\(import \|^\s*\)\"github.com/golang/protobuf/ptypes/" -- "*.go"
 # - Ensure all xds proto imports are renamed to *pb or *grpc.
 git grep '"github.com/envoyproxy/go-control-plane/envoy' -- '*.go' ':(exclude)*.pb.go' | not grep -v 'pb "\|grpc "'
 
+# - Check imports that are illegal in appengine (until Go 1.11).
+# TODO: Remove when we drop Go 1.10 support
+go list -f {{.Dir}} ./... | xargs go run test/go_vet/vet.go
+
 # - gofmt, goimports, golint (with exceptions for generated code), go vet.
 gofmt -s -d -l . 2>&1 | fail_on_output
 goimports -l . 2>&1 | not grep -vE "\.pb\.go"