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fix(otel): prevent unpaired unicode surrogate pairs from causing insert errors #2594

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Merged
merged 2 commits into from
Oct 8, 2025
Merged

fix(otel): prevent unpaired unicode surrogate pairs from causing insert errors #2594

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fc41b95
fix(otel): prevent unpaired unicode surrogate pairs from causing inse…
ericallam Oct 8, 2025
b02bfc2
only check parts of the string that are not going to get truncated
ericallam Oct 8, 2025
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121 changes: 90 additions & 31 deletions apps/webapp/app/v3/otlpExporter.server.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@ import type {
import { startSpan } from "./tracing.server";
import { enrichCreatableEvents } from "./utils/enrichCreatableEvents.server";
import { env } from "~/env.server";
import { detectBadJsonStrings } from "~/utils/detectBadJsonStrings";
import { singleton } from "~/utils/singleton";

class OTLPExporter {
private _tracer: Tracer;
Expand Down Expand Up @@ -221,18 +223,16 @@ function convertLogsToCreateableEvents(
);

const properties =
convertKeyValueItemsToMap(
truncateAttributes(log.attributes ?? [], spanAttributeValueLengthLimit),
[],
undefined,
[
truncateAttributes(
convertKeyValueItemsToMap(log.attributes ?? [], [], undefined, [
SemanticInternalAttributes.USAGE,
SemanticInternalAttributes.SPAN,
SemanticInternalAttributes.METADATA,
SemanticInternalAttributes.STYLE,
SemanticInternalAttributes.METRIC_EVENTS,
SemanticInternalAttributes.TRIGGER,
]
]),
spanAttributeValueLengthLimit
) ?? {};

return {
Expand Down Expand Up @@ -304,18 +304,16 @@ function convertSpansToCreateableEvents(
);

const properties =
convertKeyValueItemsToMap(
truncateAttributes(span.attributes ?? [], spanAttributeValueLengthLimit),
[],
undefined,
[
truncateAttributes(
convertKeyValueItemsToMap(span.attributes ?? [], [], undefined, [
SemanticInternalAttributes.USAGE,
SemanticInternalAttributes.SPAN,
SemanticInternalAttributes.METADATA,
SemanticInternalAttributes.STYLE,
SemanticInternalAttributes.METRIC_EVENTS,
SemanticInternalAttributes.TRIGGER,
]
]),
spanAttributeValueLengthLimit
) ?? {};

return {
Expand Down Expand Up @@ -774,24 +772,85 @@ function binaryToHex(buffer: Buffer | string | undefined): string | undefined {
return Buffer.from(Array.from(buffer)).toString("hex");
}

function truncateAttributes(attributes: KeyValue[], maximumLength: number = 1024): KeyValue[] {
return attributes.map((attribute) => {
return isStringValue(attribute.value)
? {
key: attribute.key,
value: {
stringValue: attribute.value.stringValue.slice(0, maximumLength),
},
}
: attribute;
});
function truncateAttributes(
attributes: Record<string, string | number | boolean | undefined> | undefined,
maximumLength: number = 1024
): Record<string, string | number | boolean | undefined> | undefined {
if (!attributes) return undefined;

const truncatedAttributes: Record<string, string | number | boolean | undefined> = {};

for (const [key, value] of Object.entries(attributes)) {
if (!key) continue;

if (typeof value === "string") {
truncatedAttributes[key] = truncateAndDetectUnpairedSurrogate(value, maximumLength);
} else {
truncatedAttributes[key] = value;
}
}

return truncatedAttributes;
}

function truncateAndDetectUnpairedSurrogate(str: string, maximumLength: number): string {
const truncatedString = smartTruncateString(str, maximumLength);

if (hasUnpairedSurrogateAtEnd(truncatedString)) {
return smartTruncateString(truncatedString, [...truncatedString].length - 1);
}

return truncatedString;
}

const ASCII_ONLY_REGEX = /^[\p{ASCII}]*$/u;

function smartTruncateString(str: string, maximumLength: number): string {
if (!str) return "";
if (str.length <= maximumLength) return str;

const checkLength = Math.min(str.length, maximumLength * 2 + 2);

if (ASCII_ONLY_REGEX.test(str.slice(0, checkLength))) {
return str.slice(0, maximumLength);
}

return [...str.slice(0, checkLength)].slice(0, maximumLength).join("");
}

function hasUnpairedSurrogateAtEnd(str: string): boolean {
if (str.length === 0) return false;

const lastCode = str.charCodeAt(str.length - 1);

// Check if last character is an unpaired high surrogate
if (lastCode >= 0xd800 && lastCode <= 0xdbff) {
return true; // High surrogate at end = unpaired
}

// Check if last character is an unpaired low surrogate
if (lastCode >= 0xdc00 && lastCode <= 0xdfff) {
// Low surrogate is only valid if preceded by high surrogate
if (str.length === 1) return true; // Single low surrogate

const secondLastCode = str.charCodeAt(str.length - 2);
if (secondLastCode < 0xd800 || secondLastCode > 0xdbff) {
return true; // Low surrogate not preceded by high surrogate
}
}

return false;
}

export const otlpExporter = new OTLPExporter(
eventRepository,
clickhouseEventRepository,
process.env.OTLP_EXPORTER_VERBOSE === "1",
process.env.SERVER_OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT
? parseInt(process.env.SERVER_OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT, 10)
: 8192
);
export const otlpExporter = singleton("otlpExporter", initializeOTLPExporter);

function initializeOTLPExporter() {
return new OTLPExporter(
eventRepository,
clickhouseEventRepository,
process.env.OTLP_EXPORTER_VERBOSE === "1",
process.env.SERVER_OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT
? parseInt(process.env.SERVER_OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT, 10)
: 8192
);
}