How deeply does 100 Go Mistakes and How to Avoid Them cover errgroup.Group?

Defines WithContext, Go, and Wait and demonstrates an indexed results handler, without detailing package internals.

Errgroup.Group

As explained in 100 Go Mistakes and How to Avoid Them

errgroup.Group is a type that coordinates a group of goroutines and records the first non-nil error returned by them.

A common mistake is launching goroutines with sync.WaitGroup but leaving error handling as an unresolved comment. Shared error slices, mutexes, or error channels add coordination complexity. errgroup.Group combines synchronization, error propagation, and context cancellation: call Go with a func() error, return failures from that function, and call Wait to obtain the first non-nil error. section 9.13

Use WithContext when parallel calls should share cancellation: an early failure can make waiting for slower calls unnecessary, provided those calls respond to the context. section 9.13

How 100 Go Mistakes and How to Avoid Them covers it

Cover of 100 Go Mistakes and How to Avoid Them

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Learn Go with Pocket-Sized Projectserrgroup.Group is a Go synchronization type that coordinates goroutines and reports an error from a failed goroutine.

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Related concepts

WaitGroupcontrasts with · WaitGroup is a synchronization type that counts concurrent operations and allows execution to wait until the counter reaches zero.
errgroup.Group.Gohas part · errgroup.Group.Go is a method that starts an error-returning function in a goroutine managed by an errgroup.Group and records its returned error.
errgroup.Group.Waithas part · errgroup.Group.Wait is a method that blocks until all functions in an errgroup.Group finish and returns the first non-nil error.
synchronizationuses · Synchronization coordinates operations, events, clocks, data, or states to establish required timing, ordering, visibility, or consistency relationships.
errgrouppart of · errgroup is a Go package that coordinates concurrent functions or goroutines, propagates their errors, and can integrate cancellation through a context.
error handlinguses · Error handling is the practice of detecting, representing, propagating, reporting, and responding to errors or failures during software operation.

This explainer was generated by Manning's knowledge graph from the text of 100 Go Mistakes and How to Avoid Them. The section links point to the parts of the book it draws on.