Have you ever had a CI job fail, and had to page though masses of logs saying things downloaded, things worked successfully, things installed, etc. before you reach the actual failure point? Have you tried searching for strings like "Error" or "Failure" only to be taken to a line that says "0 Failures" or "0 Errors", or even worse to a line that says failure, but it's turns out that it's normal for that to fail - perhaps it's part of a test of error trapping code? Sometimes you can find the error quickly by skipping to the bottom and working backwards, but if the error doesn't quite make sense you have a suspicion that something out of the ordinary may have happened earlier in the build process, but it's like a needle in a haystack to find it?

Then you need Log diff. This will eliminate everything "normal" from your logs by comparing it to logs of previous successful runs. You will be placed straight at the first line that contains something out of the ordinary, with all the normal lines collapsed down out of your way (You can expand a few lines of context if you need to figure out where you are). You can call up a side-by-side view with the closest lines on the last successful run (perhaps with a side by side view). As you scroll down, any lines that occurred in the last successful run will be hidden by default. Any lines you see will be related to the error, or to new code or tests that are part of your branch.

The whole thing runs in a browser to avoid putting load on any server. Initially you will be able to upload 2 log files, integration with github actions for logs will follow.

This project is written in Typescript with the React frontend framework, and yarn package manager. It uses the vite project for building and compiling.

Prerequisites:

• A recent version of Nodejs (nvm is a handy tool for managing multiple versions installed on the same machine)
• Yarn (See the installation instructions)
• Microsoft Visual Studio Code is recommended as it has very good TypeScript / React support and includes Live Share which allows remote paring for free. The paid versions of IntelliJ might also have good TypeScript support.

To set up on your machine:

• git clone the project
• cd log-diff
• Run yarn to install the dependencies
• Run yarn dev to run the development server
• Visit the URL it gives you in your browser - usually something like http://localhost:5173/

The development server has some tricks up it's sleeve. It will automatically compile the project when it starts up and will monitor for changes to the source and try to update them in the browser if possible. It also enhances error messages and provides debug symbols to the browser to use in it's developer tools (sourcemap files).

Additional commands you can pass to yarn are listed in the scripts section of package.json. They include:

• yarn build: Build the project
• yarn lint: Check the project with the ESLint linter that is configured
• yarn preview: Preview the site on a local web browser from the build output, without the extra features of yarn dev

Copyright 2022-2024 Diffblue Limited

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.