# Error message when creating a custom beat

**URL:** <https://discuss.elastic.co/t/error-message-when-creating-a-custom-beat/244868>\
**Category:** Beats\
**Tags:** beats-development\
**Created:** [August 13, 2020, 11:19am UTC](https://discuss.elastic.co/t/error-message-when-creating-a-custom-beat/244868 "2020-08-13T11:19:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![grobd](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/grobd/32/73884_2.png) [@grobd](https://discuss.elastic.co/u/grobd)\
**Post date:** [August 13, 2020, 11:19am UTC](https://discuss.elastic.co/t/error-message-when-creating-a-custom-beat/244868/1 "2020-08-13T11:19:09Z")

</div>

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.

```auto
    ...

    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? 🙂

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [September 10, 2020, 1:19pm UTC](https://discuss.elastic.co/t/error-message-when-creating-a-custom-beat/244868/2 "2020-09-10T13:19:14Z")

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