Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Panic when trying to serve http with embedded assets #43761

Closed
Cookie04DE opened this issue Jan 18, 2021 · 6 comments
Closed

Panic when trying to serve http with embedded assets #43761

Cookie04DE opened this issue Jan 18, 2021 · 6 comments
Labels
FrozenDueToAge

Comments

@Cookie04DE
Copy link

Cookie04DE commented Jan 18, 2021 •
edited by seankhliao

What version of Go are you using (go version)?

$ go version
go version go1.16beta1 linux/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

go env 
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/conrad/.cache/go-build"
GOENV="/home/conrad/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/media/conrad/Seagate/Programmieren/Go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/media/conrad/Seagate/Programmieren/Go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/media/conrad/Seagate/Installationen/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/media/conrad/Seagate/Installationen/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build184147953=/tmp/go-build -gno-record-gcc-switches"

What did you do?

package main

import (
	"embed"
	"net/http"
)

//go: embed assets/*
var assets embed.FS

func main() {
	fs := http.FileServer(http.FS(assets))
	http.ListenAndServe(":48784", fs)
}

I created a folder called 'assets' containing only index.html with the following content:

<html>
    <head>
    </head>
    <body>
        <h>Hello World!</h>
    </body>
</html>

I then ran go1.16beta1 run .

What did you expect to see?

No panic and the static site being served on localhost:48784.

What did you see instead?

This panic:

2021/01/18 21:26:57 http: panic serving [::1]:55146: runtime error: invalid memory address or nil pointer dereference
goroutine 6 [running]:
net/http.(*conn).serve.func1(0xc00010e960)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1824 +0x153
panic(0x663180, 0x84ba30)
        /home/conrad/sdk/go1.16beta1/src/runtime/panic.go:971 +0x47a
embed.FS.readDir(0x0, 0x6a6905, 0x1, 0x84d580, 0x7f12ea36a3a0, 0x0)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:266 +0x26
embed.FS.Open(0x0, 0x6a6905, 0x1, 0x8, 0x889f28, 0x44ed8c, 0x203000)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:285 +0xce
net/http.ioFS.Open(0x6faa40, 0x0, 0xc000016384, 0x1, 0xc000168000, 0x7f12ea36a3a0, 0xc0001179c0, 0x40f27b)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:760 +0x68
net/http.serveFile(0x6fde30, 0xc0001480e0, 0xc000162000, 0x6fad20, 0xc000012c10, 0xc000016384, 0x1, 0xc000100e01)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:597 +0x84
net/http.(*fileHandler).ServeHTTP(0xc000012c20, 0x6fde30, 0xc0001480e0, 0xc000162000)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:848 +0x9c
net/http.serverHandler.ServeHTTP(0xc000148000, 0x6fde30, 0xc0001480e0, 0xc000162000)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:2887 +0xa3
net/http.(*conn).serve(0xc00010e960, 0x6fe2a0, 0xc000028280)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1952 +0x8ed
created by net/http.(*Server).Serve
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:3013 +0x39b
2021/01/18 21:26:58 http: panic serving [::1]:55190: runtime error: invalid memory address or nil pointer dereference
goroutine 18 [running]:
net/http.(*conn).serve.func1(0xc000190000)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1824 +0x153
panic(0x663180, 0x84ba30)
        /home/conrad/sdk/go1.16beta1/src/runtime/panic.go:971 +0x47a
embed.FS.readDir(0x0, 0x6a6905, 0x1, 0x84d580, 0x7f12c1eee538, 0x0)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:266 +0x26
embed.FS.Open(0x0, 0x6a6905, 0x1, 0x8, 0x889f28, 0x64, 0x203000)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:285 +0xce
net/http.ioFS.Open(0x6faa40, 0x0, 0xc000194024, 0x1, 0x24, 0x7f12c1eee538, 0xc0000509c0, 0x40f27b)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:760 +0x68
net/http.serveFile(0x6fde30, 0xc0001b0000, 0xc00019e000, 0x6fad20, 0xc000012c10, 0xc000194024, 0x1, 0xc00018c001)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:597 +0x84
net/http.(*fileHandler).ServeHTTP(0xc000012c20, 0x6fde30, 0xc0001b0000, 0xc00019e000)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:848 +0x9c
net/http.serverHandler.ServeHTTP(0xc000148000, 0x6fde30, 0xc0001b0000, 0xc00019e000)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:2887 +0xa3
net/http.(*conn).serve(0xc000190000, 0x6fe2a0, 0xc000196000)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1952 +0x8ed
created by net/http.(*Server).Serve
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:3013 +0x39b
2021/01/18 21:27:03 http: panic serving [::1]:55398: runtime error: invalid memory address or nil pointer dereference
goroutine 8 [running]:
net/http.(*conn).serve.func1(0xc00010ea00)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1824 +0x153
panic(0x663180, 0x84ba30)
        /home/conrad/sdk/go1.16beta1/src/runtime/panic.go:971 +0x47a
embed.FS.readDir(0x0, 0x6a6905, 0x1, 0x84d580, 0x0, 0x0)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:266 +0x26
embed.FS.Open(0x0, 0x6a6905, 0x1, 0x8, 0x7f12ea36a538, 0x90, 0x203000)
        /home/conrad/sdk/go1.16beta1/src/embed/embed.go:285 +0xce
net/http.ioFS.Open(0x6faa40, 0x0, 0xc000016494, 0x1, 0x203000, 0xc0001641b8, 0xc0000559c0, 0x40f27b)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:760 +0x68
net/http.serveFile(0x6fde30, 0xc0001481c0, 0xc000162100, 0x6fad20, 0xc000012c10, 0xc000016494, 0x1, 0xc000101001)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:597 +0x84
net/http.(*fileHandler).ServeHTTP(0xc000012c20, 0x6fde30, 0xc0001481c0, 0xc000162100)
        /home/conrad/sdk/go1.16beta1/src/net/http/fs.go:848 +0x9c
net/http.serverHandler.ServeHTTP(0xc000148000, 0x6fde30, 0xc0001481c0, 0xc000162100)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:2887 +0xa3
net/http.(*conn).serve(0xc00010ea00, 0x6fe2a0, 0xc000028400)
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:1952 +0x8ed
created by net/http.(*Server).Serve
        /home/conrad/sdk/go1.16beta1/src/net/http/server.go:3013 +0x39b
@Cookie04DE Cookie04DE changed the title Panic when trying to server http with embedded assets Panic when trying to serve http with embedded assets Jan 18, 2021
@seankhliao
Copy link
Member

//go: embed should not contain a space

@seankhliao
Copy link
Member

Unlike many projects, the Go project does not use GitHub Issues for general discussion or asking questions. GitHub Issues are used for tracking bugs and proposals only.

For asking questions, see:

@Cookie04DE
Copy link
Author

Thanks, that worked. Perhaps this should produce a more helpful error, this one is a bit cryptic.

@seankhliao
Copy link
Member

there's https://go-review.googlesource.com/c/go/+/283852/ for not panicking

@bcmills
Copy link
Contributor

bcmills commented Feb 2, 2021

Duplicate of #43682

@bcmills bcmills marked this as a duplicate of #43682 Feb 2, 2021
@bcmills
Copy link
Contributor

bcmills commented Feb 2, 2021

(See related proposal #43698.)

@golang golang locked and limited conversation to collaborators Feb 2, 2022
Sign up for free to subscribe to this conversation on GitHub. Already have an account? Sign in.
Assignees
No one assigned
Labels
FrozenDueToAge
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
4 participants
@bcmills @gopherbot @seankhliao @Cookie04DE