Kubo, invalid memory address or nil pointer dereference from IpfsNode.Bootstrap

[AxelGard]

Checklist

• This is a bug report, not a question. Ask questions on discuss.ipfs.io.
• I have searched on the issue tracker for my bug.
• I am running the latest kubo version or have an issue updating.

Installation method

ipfs-desktop

Version

v.0.20.0

Config

No response

Description

I posted on the forums and stack overflow about this issue because I assumed this was my fault for doing something wrong.
However, it appears as if it is not obvious what I'm doing wrong or there is a bug.
If it is not a bug then this needs to be expressed how to do in the documentation since this is basic stuff.
Hence, why I'm posting this as an issue.

I’m getting an invalid memory address or nil pointer dereference from IpfsNode.Bootstrap I assume that there is some panic in bootstrap Round, but am I doing something wrong here? Or is there a bug? I’m using kubo v0.20.0 here is my code:

package main

import (
    "context"
    "fmt"

    "github.com/ipfs/kubo/config"
    "github.com/ipfs/kubo/core"
    "github.com/ipfs/kubo/core/bootstrap"
)

func main() {
    ctx := context.Background()
    conf := core.BuildCfg{}
    node, err := core.NewNode(ctx, &conf)
    if err != nil {
        panic(err)
    }
    peers, err := config.DefaultBootstrapPeers()
    if err != nil {
        panic(err)
    }
    bs_conf := bootstrap.BootstrapConfigWithPeers(peers)
    err = node.Bootstrap(bs_conf) // this gets nil pointer dereference
    fmt.Println("THIS LINE WILL NOT PRINT")
    if err != nil {
        panic(err)
    }
}

The full error is:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x40 pc=0xee49eb]

goroutine 69 [running]:
github.com/ipfs/kubo/core/bootstrap.bootstrapRound({0x18bf1d8?, 0xc0000b05f0?}, {0x0, 0x0}, {0x0?, 0x0?, 0x0?, 0xc0006240c0?})
        /home/axel/go/pkg/mod/github.com/ipfs/kubo@v0.20.0/core/bootstrap/bootstrap.go:118 +0xab
github.com/ipfs/kubo/core/bootstrap.Bootstrap.func1({0x18cbd58?, 0xc0006226c0?})
        /home/axel/go/pkg/mod/github.com/ipfs/kubo@v0.20.0/core/bootstrap/bootstrap.go:89 +0xdc
github.com/jbenet/goprocess.(*process).Go.func1()
        /home/axel/go/pkg/mod/github.com/jbenet/goprocess@v0.1.4/impl-mutex.go:134 +0x36
created by github.com/jbenet/goprocess.(*process).Go
        /home/axel/go/pkg/mod/github.com/jbenet/goprocess@v0.1.4/impl-mutex.go:133 +0x238
exit status 2

the bs_conf := bootstrap.BootstrapConfigWithPeers(peers) is {4 30s 10s 0x112b700}

[aschmahmann]

Closing as this seems like a forums/question issue and how to resolve the issue was described at https://discuss.ipfs.tech/t/kubo-invalid-memory-address-or-nil-pointer-dereference-from-ipfsnode-bootstrap/16417/7. If there's more discussion to be had about a bug to be addressed here the issue can be modified to describe the bug and reopened.

[AxelGard]

Thanks @aschmahmann, I will post your answer here as well. if the forum page is ever lost:

Your issue seems to be that you use conf := core.BuildCfg{} which will set BulidCfg.Offline to false which means that you will not have a libp2p node instantiated with which to bootstrap which then gives you a null reference exception since you’re trying to bootstrap using a non-existent libp2p networking host.

If you set Offline to true it won’t panic anymore since the host will start.

That being said I’m not sure exactly what you’re trying to do and maybe using kubo as a library does enough of the job for you. However, you might be better suited to using something like GitHub - ipfs/boxo: A reference library for building IPFS applications and implementations. if you’re planning on building a custom IPFS application in Go.

There’s a relatively recent doc describing some of the tradeoffs a developer might make in deciding how to move from Kubo to something similar, but more configurable in kubo/customizing.md at master · ipfs/kubo · GitHub.

by @aschmahmann