Registry / aws / alb-log-parser

alb-log-parser

library0.0.8jsnpmunverified

alb-log-parser is a utility library for Node.js designed to parse Application Load Balancer (ALB) access logs generated by AWS. It provides a function to convert raw ALB log strings into structured JavaScript objects, mapping all fields defined by AWS, including recent additions like `target_group_arn`, `trace_id`, and `classification`. The current stable version is 0.0.8, with the last publish date being July 11, 2021. As a fork of `elb-log-parser`, its release cadence is infrequent, primarily focused on adapting to changes in AWS ALB log formats and improving parsing robustness, such as correctly handling `-1` as a numeric value. It differentiates itself by offering comprehensive field support specifically for ALB logs, making it suitable for serverless architectures (e.g., AWS Lambda) that process logs from S3 buckets for analysis in systems like Elasticsearch.

aws

npm install alb-log-parser

github ↗package ↗

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

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glibc

node 18–226 runs

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Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

parse

✓ const parse = require('alb-log-parser');

✗ const { parse } = require('alb-log-parser');

This package primarily uses CommonJS `module.exports` to export the `parse` function directly. Attempting to destructure it will result in `undefined`.

parse

✓ import parse from 'alb-log-parser';

✗ import { parse } from 'alb-log-parser';

While primarily a CommonJS package, modern Node.js environments configured for ESM can import it as a default ESM import. Named imports like `import { parse }` will not work.

This quickstart demonstrates how to install `alb-log-parser` and use its primary `parse` function to convert a raw ALB access log string into a structured JavaScript object. It shows both installation and basic API usage with a sample log line.

npm install alb-log-parser // or npm install -g alb-log-parser for global CLI usage const parse = require('alb-log-parser'); const albLogLine = 'http 2020-08-27T16:35:00.166351Z app/my-loadbalancer/50dc6c495c0c9188 192.168.131.39:2817 192.168.201.251:80 0.000 0.440 0.000 200 200 1107 11912 "GET http://example.com:80/path?foo=bar&baz=bak HTTP/1.1" "Fake/1.0.0 (Linux)" - - arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/my-tg/ffffffffffffffff "Self=1-00000000-111111111111111111111111;Root=1-00000000-222222222222222222222222" "-" "-" 0 2020-08-27T16:34:59.725000Z "forward" "-" "-" "192.168.201.251:80" "200" "-" "-"'; const parsedLog = parse(albLogLine); console.log(JSON.stringify(parsedLog, null, 2)); // Example for accessing specific fields console.log(` Client IP: ${parsedLog.client}`) console.log(`Request Method: ${parsedLog.request_method}`) console.log(`Target Status Code: ${parsedLog.target_status_code}`)

Debug

Known issues

gotchaThis package is currently in `0.0.x` versioning, indicating a non-stable API. Minor version updates may introduce breaking changes without strictly adhering to semantic versioning guidelines.

fix

Rely on specific patch versions (e.g., `~0.0.8` instead of `^0.0.8`) or thoroughly test updates before deploying to production environments.

affects: >=0.0.1

gotchaAs a fork of `elb-log-parser`, this package's maintenance and feature development are independent. It may not keep pace with future changes to AWS ALB log formats or new features in the original `elb-log-parser` or other, more actively maintained ALB log parsers in different languages.

fix

Periodically review AWS documentation for ALB log format changes and verify library behavior against new log entries. Consider contributing upstream or migrating if official support or more active development becomes critical.

affects: >=0.0.1

breakingIn `v0.0.8`, the parser was updated to interpret fields with the value `"-1"` as a numeric `-1` instead of a string `"-"`. While intended as a correction, this changes the data type and value for these specific fields, potentially affecting existing data processing pipelines or schema expectations.

fix

Update consumers of the parsed log data to expect numeric `-1` for relevant fields where `"-"` previously indicated absence or a non-numeric value. Review pipelines that perform strict type checking or rely on the previous string representation.

affects: >=0.0.8

Errors

Common errors & fixes

TypeError: parse is not a function

Attempting to destructure a default export, e.g., `const { parse } = require('alb-log-parser');` or `import { parse } from 'alb-log-parser';`, when the module exports the function directly as the default export.

fix

Use `const parse = require('alb-log-parser');` for CommonJS or `import parse from 'alb-log-parser';` for ESM to correctly import the default exported function.

ReferenceError: require is not defined

Attempting to use CommonJS `require()` syntax in an ES Module (`.mjs` file or `"type": "module"` in `package.json`) context.

fix

Switch to ESM import syntax: `import parse from 'alb-log-parser';` if your project is configured for ES Modules.

Upgrade

Version history

0.0.8latest on PyPI

Audit

Dependencies

No dependency data recorded yet.

Agent activity

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Resources

githubhttps://github.com/igtm/node-alb-log-parser ↗

packagehttps://www.npmjs.com/package/alb-log-parser ↗