[processor/probabilisticsampler] panics when non-Bytes log attribute chosen

[e-dard]

Component(s)

processor/probabilisticsampler

What happened?

Description

It is possible to configure the processor to sample based upon an arbitrary attribute of each log record. Currently, if you provide an attribute that is not a Bytes typed attribute, then the collector will panic with something similar to the following:

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
    panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x102c9c0e8]

goroutine 14 [running]:
testing.tRunner.func1.2({0x102e93760, 0x1034ec850})
    /opt/homebrew/Cellar/go/1.19.5/libexec/src/testing/testing.go:1396 +0x1c8
testing.tRunner.func1()
    /opt/homebrew/Cellar/go/1.19.5/libexec/src/testing/testing.go:1399 +0x378
panic({0x102e93760, 0x1034ec850})
    /opt/homebrew/Cellar/go/1.19.5/libexec/src/runtime/panic.go:884 +0x204
go.opentelemetry.io/collector/pdata/pcommon.ByteSlice.AsRaw(...)

<snip>

Effectively, when Bytes() is called on any attribute value that is not of type AnyValue_BytesValue here:

opentelemetry-collector-contrib/processor/probabilisticsamplerprocessor/logsprocessor.go

Lines 75 to 80 in b2f0015

	if lidBytes == nil && lsp.samplingSource != "" {
	if value, ok := l.Attributes().Get(lsp.samplingSource); ok {
	tagPolicyValue = lsp.samplingSource
	lidBytes = value.Bytes().AsRaw()
	}
	}

The returned BytesSlice will be zero-initialised, resulting in the AsRaw() call panicking.

Steps to Reproduce

Configure the processor to sample based on an attribute of each log record, where the attribute is not of type Bytes e.g.,

processors:
  probabilistic_sampler:
    sampling_percentage: 15
    attribute_source: record
    from_attribute: <an_attribute_thats_not_bytes>

Expected Result

Either the attribute value is used for a sampling decision, or the log record is skipped and not sampled.

Actual Result

The collector panics.

Collector version

latest

Environment information

Environment

All

OpenTelemetry Collector configuration

No response

Log output

No response

Additional context

No response

[github-actions]

Pinging code owners:

• processor/probabilisticsampler: @jpkrohling

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• processor/probabilisticsampler: @jpkrohling

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• processor/probabilisticsampler: @jpkrohling

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[liwanxue]

facing same issue. any solutions?

[jpkrohling]

I submitted a PR to get this fixed.