Distributed Services with Go

How Logs Work

A log is an append-only sequence of records. You append records to the end of the log, and you typically read top to bottom, oldest to newest—similar to running tail -f on a file. You can log any data. People have historically used the term logs to refer to lines of text meant for humans to read, but that’s changed as more people use log systems where their “logs” are binary-encoded messages meant for other programs to read. When I talk about logs and records in this book, I’m not talking about any particular type of data. When you append a record to a log, the log assigns the record a unique and sequential offset number that acts like the ID for that record. A log is like a table that always orders the records by time and indexes ...