Fix OTLP JSON deserialization of numeric histogram bucketCounts#16376
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Fix OTLP JSON deserialization of numeric histogram bucketCounts#16376
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🚀 Dogfood this PR with:
curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 16376Or
iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 16376" |
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Pull request overview
Improves OTLP JSON metrics deserialization robustness in Aspire (Dashboard + CLI shared OTLP serializer) by accepting histogram bucketCounts emitted as JSON numbers (a common exporter deviation from protojson’s uint64-as-string requirement), preventing JsonException failures when ingesting metrics.
Changes:
- Added
StringArrayFromNumbersConverterto deserializestring[]from JSON arrays containing either string or number tokens. - Applied the converter to histogram
bucketCountsfields in the shared OTLP metrics JSON model. - Added an integration test covering numeric
bucketCountsingestion and repository persistence.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| tests/Aspire.Dashboard.Tests/Integration/OtlpHttpJsonTests.cs | Adds an integration test and sample payload to validate numeric bucketCounts are accepted and stored correctly. |
| src/Shared/Otlp/Serialization/StringArrayFromNumbersConverter.cs | Introduces a converter that reads string-or-number JSON array elements into string[]. |
| src/Shared/Otlp/Serialization/OtlpMetricsJson.cs | Annotates histogram bucket count properties to use the new converter. |
| src/Aspire.Dashboard/Aspire.Dashboard.csproj | Links the new shared converter source file into the Dashboard build. |
| src/Aspire.Cli/Aspire.Cli.csproj | Links the new shared converter source file into the CLI build. |
Some OTLP exporters send uint64 histogram bucket counts as JSON numbers instead of strings. The protojson spec requires string encoding for uint64 fields, but small values are often sent as bare numbers. Change BucketCounts from string[] to ulong[] with JsonNumberHandling (WriteAsString | AllowReadingFromString), matching the pattern used by Count, TimeUnixNano, and other uint64 properties. This lets System.Text.Json handle both string and number tokens natively without a custom converter. Also simplifies OtlpJsonProtobufConverter (removes ulong.Parse calls) and TelemetryExportService (removes ToString conversion).
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eerhardt
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🎬 CLI E2E Test Recordings — 72 recordings uploaded (commit View recordings
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This was referenced Apr 23, 2026
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Description
Some OTLP exporters (e.g. VS Code Copilot Chat) send histogram
bucketCountsas JSON numbers ([0, 2, 0, ...]) instead of strings (["0", "2", "0", ...]). While the protojson spec requires string encoding foruint64fields, many exporters emit small values as bare numbers. This causes aJsonExceptionin the Dashboard:Changes
The fix changes
BucketCountsfromstring[]toulong[]with[JsonNumberHandling(WriteAsString | AllowReadingFromString)], matching the pattern already used byCount,TimeUnixNano, and otheruint64properties in the same file. This letsSystem.Text.Jsonhandle both string and number tokens natively.OtlpMetricsJson.cs—BucketCountsonOtlpHistogramDataPointJsonandOtlpExponentialHistogramBucketsJsonchanged fromstring[]toulong[]withJsonNumberHandlingattribute.OtlpJsonProtobufConverter.cs— removedulong.Parse()calls, values are now added directly.TelemetryExportService.cs— removed.Select(v => v.ToString(...)).ToArray(), assignsulong[]directly.OtlpHttpJsonTests.cs— addedCallService_Metrics_NumericBucketCounts_Successintegration test that posts metrics JSON with numeric bucket counts and asserts histogram data (bounds + counts) is deserialized correctly end-to-end.Checklist