Skip to content

Commit

Permalink
Enable response hook to add attributes to the span
Browse files Browse the repository at this point in the history
  • Loading branch information
@scheler
scheler committed Jul 5, 2024
1 parent 3c8c1e4 commit 07f0e25
Show file tree
Hide file tree
Showing 3 changed files with 129 additions and 94 deletions.
4 changes: 4 additions & 0 deletions examples/web/examples/fetch/index.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,10 @@ registerInstrumentations({
propagateTraceHeaderCorsUrls: [
'http://localhost:8090',
],
responseHook: (span, request, response) => {
span.setAttribute('responseHook.method', request.method);
span.setAttribute('responseHook.status_code', response.status);
},
}),
],
tracerProvider: tracerProvider,
Expand Down
185 changes: 91 additions & 94 deletions plugins/web/opentelemetry-instrumentation-fetch2/src/fetch.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,44 +18,21 @@ import * as api from '@opentelemetry/api';
import {
isWrapped,
InstrumentationBase,
InstrumentationConfig,
safeExecuteInTheMiddle,
safeExecuteInTheMiddle
} from '@opentelemetry/instrumentation';
import * as core from '@opentelemetry/core';
import * as web from '@opentelemetry/sdk-trace-web';
import { AttributeNames } from './enums/AttributeNames';
import { SEMATTRS_HTTP_URL, SEMATTRS_HTTP_HOST, SEMATTRS_HTTP_METHOD, SEMATTRS_HTTP_SCHEME, SEMATTRS_HTTP_STATUS_CODE, SEMATTRS_HTTP_USER_AGENT } from '@opentelemetry/semantic-conventions';
import { FetchError, FetchResponse, SpanContextData } from './types';
import { FetchError, FetchInstrumentationConfig, FetchResponse, SpanContextData } from './types';
import { PACKAGE_NAME, PACKAGE_VERSION } from './version';
import { _globalThis } from '@opentelemetry/core';

const isNode = typeof process === 'object' && process.release?.name === 'node';
const RESOURCE_FETCH_INITIATED = '@opentelemetry/ResourceFetchInitiated'; // TODO: duplicated in resource-timing instrumentation


export interface FetchCustomAttributeFunction {
(
span: api.Span,
request: Request | RequestInit,
result: Response | FetchError
): void;
}

/**
* FetchPlugin Config
*/
export interface FetchInstrumentationConfig extends InstrumentationConfig {
// urls which should include trace headers when origin doesn't match
propagateTraceHeaderCorsUrls?: web.PropagateTraceHeaderCorsUrls;
/**
* URLs that partially match any regex in ignoreUrls will not be traced.
* In addition, URLs that are _exact matches_ of strings in ignoreUrls will
* also not be traced.
*/
ignoreUrls?: Array<string | RegExp>;
/** Function for adding custom attributes on the span */
applyCustomAttributesOnSpan?: FetchCustomAttributeFunction;
}

/**
* This class represents a fetch plugin for auto instrumentation;
Expand Down Expand Up @@ -103,8 +80,7 @@ export class FetchInstrumentation extends InstrumentationBase {
},
});
}

/**
/**
* Finish span, add attributes.
* @param span
* @param endTime
Expand All @@ -115,14 +91,45 @@ export class FetchInstrumentation extends InstrumentationBase {
response: FetchResponse,
spanContextData: SpanContextData,
endTime: api.HrTime
) {
): Promise<void> {

return new Promise((resolve, reject) => {
try {
spanContextData.endTime = endTime;
document.dispatchEvent(new CustomEvent(RESOURCE_FETCH_INITIATED, {
detail: spanContextData
}));
this._addFinalSpanAttributes(span, response);
span.end(endTime);
} finally {
resolve();
}
});
}

spanContextData.endTime = endTime;
document.dispatchEvent(new CustomEvent(RESOURCE_FETCH_INITIATED, {
detail: spanContextData
}));
this._addFinalSpanAttributes(span, response);
span.end(endTime);
private _executeResponseHook(
span: api.Span,
request: Request | RequestInit,
result: Response | FetchError
) : Promise<void> {
if (!this._config.responseHook) {
return Promise.resolve();
}
return new Promise((resolve) => {
safeExecuteInTheMiddle(
() => {
this._config.responseHook?.(span, request, result);
},
err => {
if (err) {
this._diag.error('Error running response hook', err);
}
},
true
);
resolve();

});
}

/**
Expand Down Expand Up @@ -211,6 +218,7 @@ export class FetchInstrumentation extends InstrumentationBase {
const startTime = core.hrTime();
const createdSpan = plugin._createSpan(url, startTime, options);
if (!createdSpan) {
// url was ignored and no span was created, hence no need to wrap fetch
return original.apply(this, args);
}

Expand All @@ -223,81 +231,92 @@ export class FetchInstrumentation extends InstrumentationBase {
spanId: createdSpan.spanContext().spanId
}



function endSpanOnError(span: api.Span, endTime: api.HrTime, error: FetchError) {
plugin._applyAttributesAfterFetch(span, options, error);
plugin._endSpan(span, {
status: error.status || 0,
statusText: error.message,
url,
}, spanContextData, endTime);
function endSpanOnError(span: api.Span, endTime: api.HrTime, error: FetchError): Promise<void> {
return plugin._executeResponseHook(span, options, error)
.then(() => {
plugin._endSpan(span, {
status: error.status || 0,
statusText: error.message,
url,
}, spanContextData, endTime);
});
}

function endSpanOnSuccess(span: api.Span, endTime: api.HrTime, response: Response) {
plugin._applyAttributesAfterFetch(span, options, response);
if (response.status >= 200 && response.status < 400) {
plugin._endSpan(span, response, spanContextData, endTime);
} else {
plugin._endSpan(span, {
status: response.status,
statusText: response.statusText,
url,
}, spanContextData, endTime);
}
function endSpanOnSuccess(span: api.Span, endTime: api.HrTime, response: Response): Promise<void> {
return plugin._executeResponseHook(span, options, response)
.then(() => {
if (response.status >= 200 && response.status < 400) {
plugin._endSpan(span, response, spanContextData, endTime);
} else {
plugin._endSpan(span, {
status: response.status,
statusText: response.statusText,
url,
}, spanContextData, endTime);
}
})
}

function onSuccess(
span: api.Span,
resolve: (value: Response | PromiseLike<Response>) => void,
response: Response
): void {
// For client spans, the span should end at the earliest when the response is received
// and not wait for the body to be read. However, since we need attributes that are based on the
// response, we will proceed to read the body and end the span using a endTime that is now.
const endTime = core.millisToHrTime(Date.now());
): Promise<void> {
return new Promise(() => {
// For client spans, the span should end at the earliest when the response is received
// and not wait for the body to be read. However, since we need attributes that are based on the
// response, we will proceed to read the body and end the span using a endTime that is now.
const endTime = core.millisToHrTime(Date.now());

try {
const resClone = response.clone();
const resClone4Hook = response.clone();
const body = resClone.body;
if (body) {
const reader = body.getReader();
const read = (): void => {
// FIXME: Find out the entire body is ready is read; it will buffer the entire body in memory,
// which might not be desirable for large responses.
reader.read().then(
({ done }) => {
if (done) {
endSpanOnSuccess(span, endTime, resClone4Hook);
endSpanOnSuccess(span, endTime, resClone4Hook)
.finally(() => {
resolve(response);
});
} else {
read();
}
},
error => {
endSpanOnError(span, endTime, error);
endSpanOnError(span, endTime, error)
.finally(() => {
resolve(response);
});
}
);
};
read();
} else {
// some older browsers don't have .body implemented
endSpanOnSuccess(span, endTime, response);
endSpanOnSuccess(span, endTime, response)
.finally(() => {
resolve(response);
});
}
} finally {
resolve(response);
}
})
}


function onError(
span: api.Span,
reject: (reason?: unknown) => void,
error: FetchError
) {
): Promise<void> {
const endTime = core.millisToHrTime(Date.now());
try {
endSpanOnError(span, endTime, error);
} finally {
reject(error);
}
return endSpanOnError(span, endTime, error)
.finally(() => {
reject(error);
});
}

return new Promise((resolve, reject) => {
Expand All @@ -323,28 +342,6 @@ export class FetchInstrumentation extends InstrumentationBase {
};
}

private _applyAttributesAfterFetch(
span: api.Span,
request: Request | RequestInit,
result: Response | FetchError
) {
const applyCustomAttributesOnSpan =
this._config.applyCustomAttributesOnSpan;
if (applyCustomAttributesOnSpan) {
safeExecuteInTheMiddle(
() => applyCustomAttributesOnSpan(span, request, result),
error => {
if (!error) {
return;
}

this._diag.error('applyCustomAttributesOnSpan', error);
},
true
);
}
}

/**
* implements enable function
*/
Expand Down
34 changes: 34 additions & 0 deletions plugins/web/opentelemetry-instrumentation-fetch2/src/types.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,41 @@
*/

import * as api from '@opentelemetry/api';
import { InstrumentationConfig } from '@opentelemetry/instrumentation';
import * as web from '@opentelemetry/sdk-trace-web';

/**
* Hook function to be called after fetch is executed and before ending the span.
* FIXME: The hook function doesn't have access to the fetch url if the request
* is a RequestInit object
*/
export interface FetchInstrumentationExecutionResponseHook {
(
span: api.Span,
request: Request | RequestInit,
result: Response | FetchError
): void;
}

/**
* FetchPlugin Config
*/
export interface FetchInstrumentationConfig extends InstrumentationConfig {
// urls which should include trace headers when origin doesn't match
propagateTraceHeaderCorsUrls?: web.PropagateTraceHeaderCorsUrls;
/**
* URLs that partially match any regex in ignoreUrls will not be traced.
* In addition, URLs that are _exact matches_ of strings in ignoreUrls will
* also not be traced.
*/
ignoreUrls?: Array<string | RegExp>;

/** Hook function to be called after fetch is executed and before ending the span.
* This is useful for adding custom attributes to the span based on the fetch's
* request and response
*/
responseHook?: FetchInstrumentationExecutionResponseHook;
}
/**
* Interface used to provide information to finish span on fetch response
*/
Expand Down

0 comments on commit 07f0e25

Please sign in to comment.