Logging and error handling in a web application drastically aids in the troubleshooting of the application by operations team members. Reliable and deterministic error handling is essential to creating robust and reliable applications. The ability to provide team members the relevant information about the state of the running service is also important. By providing logging and tracing patterns within your service, you will be able to quickly isolate what is happening based on the logged information.

So much time is dedicated in application development to working out the functionality of the success case. This makes sense, as the service or application needs to function in the first place. It is very often easy to overlook the not-so-successful cases. By not handling errors well, your application will likely not be resilient, or fail with grace.

In this chapter, we will be covering two often overlooked, but critically important, aspects of web application development. We will start by looking at how logging can be accomplished within the confines of the Echo framework. We will then look at how we can use Echo to capture the handler function and middleware errors before they are broadcast to the consumers of your service. In this chapter, we will explore the following topics:

• Logging
  • Echo's Logger interface, and how to extend the logger
  • Typical use cases of the logger within your application
  • Log levels and the appropriate use of log levels.
  • Introducing to the logging middleware
• Error handling
  • The error-handling function and capabilities built into Echo
  • How to customize error handling with Echo