Error message when creating a custom beat

[grobd (Daniel Grob)]

Hi,

i just wanted to create a new community beat by sending the number of open files to Elasticsearch using the command lsof | wc -l. I have also checked the documentation in the beats section and followed it very carefully. When I execute the command mage GenerateCustomBeat I get the following error message.

    ...

    go: github.com/dlclark/regexp2 upgrade => v1.2.0
    go: github.com/pkg/errors upgrade => v0.9.1
    go: go.uber.org/zap upgrade => v1.15.0
    go: github.com/hashicorp/go-multierror upgrade => v1.1.0
    go: go.elastic.co/ecszap upgrade => v0.2.0
    go: github.com/mattn/go-colorable upgrade => v0.1.7
    go: github.com/jstemmer/go-junit-report upgrade => v0.9.1
    go: github.com/prometheus/procfs upgrade => v0.1.3
    go: github.com/elastic/go-ucfg upgrade => v0.8.3
    go: github.com/go-sourcemap/sourcemap upgrade => v2.1.3+incompatible
    go: go.uber.org/multierr upgrade => v1.5.0
    go: github.com/hashicorp/errwrap upgrade => v1.0.0
    go: howett.net/plist upgrade => v0.0.0-20200419221736-3b63eb3a43b5
    go: go.elastic.co/apm upgrade => v1.8.0
    go: github.com/dop251/goja upgrade => v0.0.0-20200811154920-cd0eddb06559
    go: github.com/dop251/goja_nodejs upgrade => v0.0.0-20200811150831-9bc458b4bbeb
    /home/grobd/go/pkg/mod/github.com/elastic/beats/v7@v7.0.0-alpha2.0.20200813103117-dbd6e3615f7a/libbeat/scripts/Makefile:295: warning: overriding recipe for target 'test'
    /home/grobd/go/pkg/mod/github.com/elastic/beats/v7@v7.0.0-alpha2.0.20200813103117-dbd6e3615f7a/libbeat/scripts/Makefile:137: warning: ignoring old recipe for target 'test'
    # github.com/dop251/goja_nodejs/require
    ../../../../pkg/mod/github.com/dop251/goja_nodejs@v0.0.0-20200811150831-9bc458b4bbeb/require/resolve.go:169:14: undefined: goja.StackFrame
    ../../../../pkg/mod/github.com/dop251/goja_nodejs@v0.0.0-20200811150831-9bc458b4bbeb/require/resolve.go:170:21: r.runtime.CaptureCallStack undefined (type *goja.Runtime has no field or method CaptureCallStack)
    Error: error compiling magefiles
    make: *** [fields] Error 1
    Error: running "make update" failed with exit code 2

Can a clever mind from this forum help me?