fix: recover from exporter panic in our custom batch_span_processor

[tim-mwangi]

Description

Sometimes the exporter panics leading the agent to crash. This change will recover from the panic.

Panic stacktrace:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x4742d0]

goroutine 198 [running]:
google.golang.org/protobuf/encoding/protowire.AppendString(...)
  /root/go/pkg/mod/google.golang.org/[email protected]/encoding/protowire/wire.go:455
google.golang.org/protobuf/internal/impl.appendStringValidateUTF8({0xc00853a000?, 0x413d64?, 0xc002ecb058?}, {0x16?}, 0xc002ecb070?, {0x6b?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_gen.go:4958 +0x95
google.golang.org/protobuf/internal/impl.(*MessageInfo).initOneofFieldCoders.func4({0xc00853a000, 0x291, 0xb49}, {0x413d64?}, 0xc002ecb0b0?, {0x16?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:96 +0x5d
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc0000e1500, {0xc00853a000?, 0xaa?, 0xe?}, {0x9?}, {0x8f?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.appendMessageInfo({0xc00853a000?, 0xc002ecb180?, 0x87efcc?}, {0x20000c0000e1500?}, 0xc002f42628, {0x85?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:238 +0xaa
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc0000e18d8, {0xc00853a000?, 0x869b68?, 0x1d?}, {0x866e49?}, {0x0?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.appendMessageSliceInfo({0xc00853a000?, 0xc002ecb2b8?, 0x87f585?}, {0xc00853a000?}, 0xc00387dc40, {0x88?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:485 +0xf1
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc0001c0cd8, {0xc00853a000?, 0x85194a?, 0x525?}, {0xc00853a000?}, {0x60?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.appendMessageSliceInfo({0xc00853a000?, 0xc002ecb3b0?, 0x87f585?}, {0xc00853a000?}, 0xc0037830c8, {0x1?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:485 +0xf1
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc0001c0b90, {0xc00853a000?, 0x85194a?, 0xa9c?}, {0xc00853a000?}, {0x90?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.appendMessageSliceInfo({0xc00853a000?, 0x0?, 0x0?}, {0xc0006f0020?}, 0xc003782f28, {0xf3?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:485 +0xf1
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc0001c0a48, {0xc00853a000?, 0x6000?, 0xb46?}, {0x102ecb4e8?}, {0x5?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.appendMessageSliceInfo({0xc00853a000?, 0xc002ecb568?, 0x42727c?}, {0x351b1c0?}, 0xc00057a990, {0x68?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/codec_field.go:485 +0xf1
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshalAppendPointer(0xc000508400, {0xc00853a000?, 0xc00d774270?, 0x1010001d39601?}, {0x7f6a0012cd68?}, {0xc8?})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:139 +0x13f
google.golang.org/protobuf/internal/impl.(*MessageInfo).marshal(0xc00853a000?, {{}, {0x1fa6b08, 0xc00eb07400}, {0xc00853a000, 0x0, 0xb49}, 0x2})
  /root/go/pkg/mod/google.golang.org/[email protected]/internal/impl/encode.go:107 +0x85
google.golang.org/protobuf/proto.MarshalOptions.marshal({{}, 0xf8?, 0x0, 0x0}, {0x0, 0x0, 0x0}, {0x1fa6b08, 0xc00eb07400})
  /root/go/pkg/mod/google.golang.org/[email protected]/proto/encode.go:166 +0x25d
google.golang.org/protobuf/proto.MarshalOptions.MarshalAppend({{}, 0x60?, 0xf6?, 0xb0?}, {0x0, 0x0, 0x0}, {0x1f805a0?, 0xc00eb07400?})
  /root/go/pkg/mod/google.golang.org/[email protected]/proto/encode.go:125 +0x73
github.com/golang/protobuf/proto.marshalAppend({0x0, 0x0, 0x0}, {0x7f6a5c9fe970?, 0xc00eb07400?}, 0xc8?)
  /root/go/pkg/mod/github.com/golang/[email protected]/proto/wire.go:40 +0x9e
github.com/golang/protobuf/proto.Marshal(...)
  /root/go/pkg/mod/github.com/golang/[email protected]/proto/wire.go:23
google.golang.org/grpc/encoding/proto.codec.Marshal({}, {0x1b0f660?, 0xc00eb07400})
  /root/go/pkg/mod/google.golang.org/[email protected]/encoding/proto/proto.go:45 +0x4d
google.golang.org/grpc.encode({0x7f6a5c9fe900?, 0x3518da0?}, {0x1b0f660?, 0xc00eb07400?})
  /root/go/pkg/mod/google.golang.org/[email protected]/rpc_util.go:633 +0x3e
google.golang.org/grpc.prepareMsg({0x1b0f660?, 0xc00eb07400?}, {0x7f6a5c9fe900?, 0x3518da0?}, {0x0, 0x0}, {0x0, 0x0})
  /root/go/pkg/mod/google.golang.org/[email protected]/stream.go:1770 +0xc7
google.golang.org/grpc.(*clientStream).SendMsg(0xc008e4eea0, {0x1b0f660?, 0xc00eb07400})
  /root/go/pkg/mod/google.golang.org/[email protected]/stream.go:892 +0xf2
google.golang.org/grpc.invoke({0x1f97b68?, 0xc011ab9030?}, {0x1d39612?, 0x7f69f573e0e8?}, {0x1b0f660, 0xc00eb07400}, {0x1b0f720, 0xc00d774120}, 0x0?, {0x0, ...})
  /root/go/pkg/mod/google.golang.org/[email protected]/call.go:70 +0x9f
google.golang.org/grpc.(*ClientConn).Invoke(0xc006090000, {0x1f97b68?, 0xc011ab9030?}, {0x1d39612?, 0xc00eb07400?}, {0x1b0f660?, 0xc00eb07400?}, {0x1b0f720?, 0xc00d774120?}, {0x0, ...})
  /root/go/pkg/mod/google.golang.org/[email protected]/call.go:37 +0x23f
go.opentelemetry.io/proto/otlp/collector/trace/v1.(*traceServiceClient).Export(0xc0034865b0, {0x1f97b68, 0xc011ab9030}, 0xc012c2e060?, {0x0, 0x0, 0x0})
  /root/go/pkg/mod/go.opentelemetry.io/proto/[email protected]/collector/trace/v1/trace_service_grpc.pb.go:40 +0xcb
go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc.(*client).UploadTraces.func1({0x1f97b68, 0xc011ab9030})
  /root/go/pkg/mod/go.opentelemetry.io/otel/exporters/otlp/otlptrace/[email protected]/client.go:204 +0xc9
go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc.newClient.Config.RequestFunc.func2({0x1f97b68, 0xc011ab9030}, 0xc00d7740f0)
  /root/go/pkg/mod/go.opentelemetry.io/otel/exporters/otlp/otlptrace/[email protected]/internal/retry/retry.go:98 +0xfb
go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc.(*client).UploadTraces(0xc00608e000, {0x1f97b68?, 0xc011ab8f50?}, {0xc0006f0028, 0x1, 0x1})
  /root/go/pkg/mod/go.opentelemetry.io/otel/exporters/otlp/otlptrace/[email protected]/client.go:203 +0x18c
go.opentelemetry.io/otel/exporters/otlp/otlptrace.(*Exporter).ExportSpans(0xc0037084b0, {0x1f97b68, 0xc011ab8f50}, {0xc006092000?, 0xc011b10f0a?, 0xc003496ea0?})
  /root/go/pkg/mod/go.opentelemetry.io/otel/exporters/otlp/[email protected]/exporter.go:47 +0x63
github.com/hypertrace/goagent/instrumentation/opentelemetry/batchspanprocessor.(*batchSpanProcessor).exportSpans(0xc000b60270, {0x1f97af8, 0xc00358c230?})
  /root/go/pkg/mod/github.com/hypertrace/[email protected]/instrumentation/opentelemetry/batchspanprocessor/batch_span_processor.modified.go:288 +0x245
github.com/hypertrace/goagent/instrumentation/opentelemetry/batchspanprocessor.(*batchSpanProcessor).processQueue(0xc000b60270)
  /root/go/pkg/mod/github.com/hypertrace/[email protected]/instrumentation/opentelemetry/batchspanprocessor/batch_span_processor.modified.go:316 +0x38a
github.com/hypertrace/goagent/instrumentation/opentelemetry/batchspanprocessor.NewBatchSpanProcessor.func1()
  /root/go/pkg/mod/github.com/hypertrace/[email protected]/instrumentation/opentelemetry/batchspanprocessor/batch_span_processor.modified.go:128 +0x54
created by github.com/hypertrace/goagent/instrumentation/opentelemetry/batchspanprocessor.NewBatchSpanProcessor in goroutine 38
  /root/go/pkg/mod/github.com/hypertrace/[email protected]/instrumentation/opentelemetry/batchspanprocessor/batch_span_processor.modified.go:126 +0x5e7

You should see an error message like

2024/05/24 10:45:57 logger.go:24: "msg"="recovering from a panic" "error"="panic value: panic span in span list"

Testing

Unit and local dev tests.

Checklist:

• [ ✅ ] My changes generate no new warnings
• [✅ ] I have added tests that prove my fix is effective or that my feature works
• [✅ ] Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.15%. Comparing base (d232486) to head (ff994c1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #230      +/-   ##
==========================================
+ Coverage   57.93%   60.15%   +2.21%     
==========================================
  Files          69       69              
  Lines        2746     2753       +7     
==========================================
+ Hits         1591     1656      +65     
+ Misses       1085     1019      -66     
- Partials       70       78       +8     

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