main function is not necessarily the first thing run.

If there is a function name init, that will run first.

If your main package imports other packages, and they have init functions, they will also be run before your main function starts.

init is a bit of black magic, and there are other ways to initialise resource that are more clear to the control flow. Like declaring variable at package scope with functions.

References

• John Arundel, For the Love of Go