Lectures

We break down two different meanings of “time” in Go: an instant ( time.Time) and a duration ( time.Duration). We learn how to get “now” via time.Now(), create a fixed date via time.Date(), check “time not set” with IsZero(), specify intervals correctly ( 150 * time.Millisecond), and do “proper math” with time via Add/ Sub and the measurement idiom time.Since.

We break down “time arithmetic” in Go: how to shift a moment correctly with Add, get a duration with Sub, measure “how much time has passed” with time.Since and “how much time is left” with time.Until. Separately—safe moment comparisons with Before/ After/ Equal and an important idea: UTC vs Local is about representation, not about changing the event.

We break down how to convert time.Time to a string and back in Go: the “magic” layout (a template based on a reference date), formatting via t.Format, parsing via time.Parse and time.ParseInLocation, and why it’s beneficial to use time.RFC3339 for the “machine world.” At the end: a practical example and a list of common mistakes (about "YYYY-MM-DD", mixing up 04/ 05, ignoring error, and time zones).

We break down how to wait in Go “for a time event” rather than just “pause”: a one-shot timer via time.After and regular ticks via time.NewTicker. In practice, we will see that both tools return a time channel ( <- chan time.Time), learn to read an event with the <- operator, properly stop a ticker via defer ticker . Stop (), and discuss common mistakes (forgot to read from the channel, did not stop the ticker, expected perfect accuracy, confused a timeout with cancellation via context).

We break down the difference between “pause and continue” and “the operation must meet a deadline”: when time.After (a delay) is appropriate, and when you need context.WithTimeout (a deadline as part of the contract). We also cover cooperative cancellation via ctx.Err(), the mandatory defer cancel(), an example using the mini app notebox, and correct timeout error handling via errors.Is and context.DeadlineExceeded.