英文:
Golang: net/http client nil when calling struct is passed to a go routine
问题
遇到了一个有趣的问题，即net/http(*Client)指针，特别是gcp go sdk compute.Operation包，尝试使用nil的http客户端发出请求，但只有在go例程中使用时才会出现此问题。这是一个示例：
import (
compute "cloud.google.com/go/compute/apiv1"
computepb "google.golang.org/genproto/googleapis/cloud/compute/v1"
)
func WaitForImages(op *compute.Operation, wg *sync.WaitGroup) {
defer wg.Done()
op.Wait(ctx)
// 在创建完镜像后执行一些操作
}
func TakeImage(context context.Context, req *computepb.InsertImageRequest, wg *sync.WaitGroup) {
c, err := compute.NewImagesRESTClient(ctx)
defer c.Close()
if err != nil {
return
}
op, err := c.Insert(ctx, req)
if err != nil {
return
}
wg.Add(1)
go WaitForImages(op, wg)
}
func Main() {
images := [//图片列表]
var wg *sync.WaitGroup = &sync.WaitGroup{}
ctx := context.TODO()
for _, img := range images {
img := img
req := &computepb.InsertImageRequest{
Project: myProject,
ImageResource: &computepb.Image{
Name: &img,
SourceDisk: &img,
},
}
TakeImage(ctx, req, wg)
}
wg.Wait()
}
这是我得到的错误信息：
4 0x00000000006ee4d7 in net/http.(*Client).deadline
at /usr/lib/go-1.19beta1/src/net/http/client.go:188
5 0x00000000006f1105 in net/http.(*Client).do
at /usr/lib/go-1.19beta1/src/net/http/client.go:599
6 0x00000000006f0f4f in net/http.(*Client).Do
at /usr/lib/go-1.19beta1/src/net/http/client.go:581
7 0x00000000006f08a5 in net/http.(*Client).Get
只有在go例程中执行op.Wait(ctx)时才会出现此问题。如果我正常等待它，就不会出现问题。我的实际程序要长得多，我无法运行到程序的最后，实际上，如果我在调试器上点击"step"相对较慢，它在几行代码后就会发生panic，但在全速运行时，有时我可以发出2-3个镜像请求，有时只有1个。我尝试关闭golang垃圾收集器，以防它破坏了http客户端，但没有成功。
英文:
Having an interesting issue where the net/http(*Client) pointer, specifically the gcp go sdk compute.Operation package attempts to make a request with a nil http client but only when used in a go routine. Here is an example
import (
compute "cloud.google.com/go/compute/apiv1"
computepb "google.golang.org/genproto/googleapis/cloud/compute/v1"
)
func WaitForImages(op *compute.Operation, wg *sync.WaitGroup) {
defer wg.Done()
op.Wait(ctx)
// Do some stuff after the image is made
}
func TakeImage(context context.Context, req *computepb.InsertImageRequest, wg *sync.WaitGroup) {
c, err := compute.NewImagesRESTClient(ctx)
defer c.Close()
if err != nil {
return
}
op, err := c.Insert(ctx, req)
if err != nil {
return
}
wg.Add(1)
go WaitForImages(op, wg)
}
func Main() {
images := [//List of images]
var wg *sync.WaitGroup = &sync.WaitGroup{}
ctx := context.TODO()
for _, img := range images {
img := img
req := &computepb.InsertImageRequest{
Project: myProject,
ImageResource: &computepb.Image{
Name: &img,
SourceDisk: &img,
},
}
TakeImage(ctx, req, wg)
}
wg.Wait()
}
This is the error I get
4 0x00000000006ee4d7 in net/http.(*Client).deadline
at /usr/lib/go-1.19beta1/src/net/http/client.go:188
5 0x00000000006f1105 in net/http.(*Client).do
at /usr/lib/go-1.19beta1/src/net/http/client.go:599
6 0x00000000006f0f4f in net/http.(*Client).Do
at /usr/lib/go-1.19beta1/src/net/http/client.go:581
7 0x00000000006f08a5 in net/http.(*Client).Get
This only happens if I do the op.Wait(ctx) inside a go routine. If I just wait for it regularly I get no issue. My actual program is much longer and I don't make it to the end of that program, in fact if I hit "step" on the debugger relatively slowly it panics after just a few lines, but in a full speed run sometimes I can make 2-3 image requests sometimes only 1. I tried turning off the golang garbage collector on the chance it was destroying the http client but had no luck.
答案1
得分: 1
问题出在c.Close()的调用上。尽管gcp返回一个新的compute.Operation客户端，但它仍然依赖于旧的compute.ImagesClient。在*compute.Operation.Wait()调用之前调用close会导致空指针解引用。
英文:
The issue was the c.Close() call. Even though gcp returns a new *compute.Operation client it is still reliant on the old *compute.ImagesClient. Calling close before the *compute.Operation.Wait() call causes a nil pointer dereference.
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