Gathering detailed insights and metrics for @dotcom-reliability-kit/middleware-log-errors
Gathering detailed insights and metrics for @dotcom-reliability-kit/middleware-log-errors
🪨 A well tested suite of tools designed to help FT.com applications be more reliable and measurable
5.0.3
9
MIT
JavaScript
10.09 kB
Installations
npm install @dotcom-reliability-kit/middleware-log-errorsDeveloper Guide
BETA
Typescript
Yes
Module System
CommonJS
Min. Node Version
20.x || 22.x
Node Version
22.13.1
NPM Version
10.9.2
Releases
459
middleware-allow-request-methods: v1.1.0
middleware-allow-request-methods-v1.1.0
Updated on May 08, 2025
opentelemetry: v3.1.0
opentelemetry-v3.1.0
Updated on May 08, 2025
serialize-request: v4.1.0
serialize-request-v4.1.0
Updated on May 08, 2025
serialize-error: v4.1.0
serialize-error-v4.1.0
Updated on May 08, 2025
middleware-render-error-info: v6.1.0
middleware-render-error-info-v6.1.0
Updated on May 08, 2025
middleware-log-errors: v5.1.0
middleware-log-errors-v5.1.0
Updated on May 08, 2025
Languages
4
JavaScript
TypeScript
CSS
Shell
JavaScript (98.43%)
TypeScript (1.11%)
CSS (0.32%)
Shell (0.14%)
Developer
Financial-Times
Download Statistics
Total Downloads
0
Last Day
0
Last Week
0
Last Month
0
Last Year
0
GitHub Statistics
MIT License
9 Stars
1,172 Commits
51 Watchers
13 Branches
33 Contributors
Updated on Jun 04, 2025
Maintainers
5
Package Meta Information
Latest Version
5.0.3
Package Id
@dotcom-reliability-kit/middleware-log-errors@5.0.3
Unpacked Size
10.09 kB
Size
3.79 kB
File Count
4
NPM Version
10.9.2
Node Version
22.13.1
Published on
Apr 09, 2025
Total Downloads
Cumulative downloads
Total Downloads
NaN
Last Day
0%
NaN
Compared to previous day
Last Week
0%
NaN
Compared to previous week
Last Month
0%
NaN
Compared to previous month
Last Year
0%
NaN
Compared to previous year
Weekly Downloads
Monthly Downloads
Yearly Downloads
Dependencies
1
Dev Dependencies
2
@dotcom-reliability-kit/middleware-log-errors
Express middleware to consistently log errors. This module is part of FT.com Reliability Kit.
Usage
Install @dotcom-reliability-kit/middleware-log-errors as a dependency:
1npm install --save @dotcom-reliability-kit/middleware-log-errors
Include in your code:
1import createErrorLogger from '@dotcom-reliability-kit/middleware-log-errors'; 2// or 3const createErrorLogger = require('@dotcom-reliability-kit/middleware-log-errors');
createErrorLogger
The createErrorLogger function can be used to generate Express middleware which logs errors to the console and Splunk via Reliability Kit logger.
[!CAUTION]
This middleware must be added to your Express app after all your application routes – you won't get error logs for any routes which are mounted after this middleware.
1const app = express(); 2// App routes go here 3app.use(createErrorLogger());
This will automatically serialize error objects and log them along with a serialized HTTP request which lead to the error being thrown. The information logged looks like this:
1{ 2 event: 'HANDLED_ERROR', 3 message: 'Error: something went wrong', 4 5 error: { 6 code: 'EXAMPLE_CODE', 7 message: 'Something went wrong' 8 // etc. (see `@dotcom-reliability-kit/serialize-error` linked above 9 // for information about the logged properties 10 }, 11 12 request: { 13 id: 'abc123', 14 method: 'GET', 15 url: '/' 16 // etc. (see `dotcom-reliability-kit/serialize-request` linked above 17 // for information about the logged properties) 18 }, 19 20 app: { 21 commit: '137da65185397a7d699ed54c3052d10d83e82137', 22 name: 'example-app', 23 nodeVersion: '22.13.0', 24 region: 'EU', 25 releaseDate: '2022-07-25T01:37:00Z' 26 } 27}
Configuration options
Config options can be passed into the createErrorLogger function as an object with any of the keys below.
1app.use(createErrorLogger({
2 // Config options go here
3}));options.filter
A function used to determine whether a particular error or request should be logged. This must be a Function which returns a Boolean and accepts both an error object and an Express Request object:
1type ErrorLoggingFilter = (error: any, request: express.Request) => boolean;
If the function returns true then the error and request details will be logged. Otherwise no logs will be output.
[!WARNING]
This option can be dangerous, misconfiguring it can result in a loss of log information. Consider whether you definitely need to filter logs before using, sometimes it's better to have a few too many logs than miss an important one.
Example of usage:
1app.use(createErrorLogger({ 2 filter: (error, request) => { 3 if (request.url === '/deliberate-erroring-endpoint') { 4 return false; 5 } 6 if (error?.code === 'ERROR_WE_DO_NOT_CARE_ABOUT') { 7 return false; 8 } 9 return true; 10 } 11}));
options.includeHeaders
An array of request headers to include in the serialized request object. This must be an Array of Strings, with each string being a header name. It's important that you do not include headers which include personally-identifiable-information, API keys, or other privileged information. This option gets passed directly into dotcom-reliability-kit/serialize-request which has further documentation.
This option defaults to:
1[ 2 'accept', 3 'accept-encoding', 4 'accept-language', 5 'content-type', 6 'referer', 7 'user-agent' 8]
Example of usage:
1app.use(createErrorLogger({ 2 includeHeaders: [ 3 'accept', 4 'content-length', 5 'content-type', 6 'user-agent' 7 ] 8}));
The default set of headers is also available to use, so that you don't need to repeat them if you want to add new included headers. You'll need to import @dotcom-reliability-kit/serialize-request, then these headers are available:
1const { DEFAULT_INCLUDED_HEADERS } = require('@dotcom-reliability-kit/serialize-request'); 2 3app.use(createErrorLogger({ 4 includeHeaders: [ 5 ...DEFAULT_INCLUDED_HEADERS, 6 'my-custom-header' 7 ] 8}));
[!NOTE]
There's no need to include thex-request-idheader in this array, as this is automatically included asrequest.idin the logs.
options.logger
A logger object which implements two methods, error and warn, which have the following permissive signature:
1type LogMethod = (...logData: any) => any;
This is passed directly onto the relevant log-error method, see the documentation for that package for more details.
options.logUserErrorsAsWarnings
A boolean indicating whether to log user errors (those with a 400–499 status property) with a level of warn rather than error. This helps to reduce the amount of error-level logs that you need to focus on.
This option defaults to false.
Migrating
Consult the Migration Guide if you're trying to migrate to a later major version of this package.
Contributing
See the central contributing guide for Reliability Kit.
License
Licensed under the MIT license.
Copyright © 2022, The Financial Times Ltd.
No vulnerabilities found.
No security vulnerabilities found.