标签：#parallelsteps

A small word that changes the rhythm of a job For as long as I have been writing Actions workflows I have been carrying a quiet workaround in my head. Want to warm a cache while the build runs? Append & to the shell command, then squint at logs that arrive out of order and pray the job doesn't exit on you. It worked, sort of. It also meant that anything more interesting than "run one thing, then the next thing" lived as folklore, hidden inside run: blocks. GitHub closed that gap this week. On June 25 the Actions changelog announced that steps inside a job can now run concurrently, marked with a new background keyword and supported by helpers to wait for them and cancel them. Until now, the changelog notes, every step in a workflow ran in sequence, with each step starting only after the previous one completed. That single rule has shaped every workflow I have ever written. It is gone, and the replacement is the kind of feature you don't notice until the day you reach for it and it's there. What the keywords actually do There are four pieces, all of them documented in the announcement. background: true is the entry point. Set it on a step and that step starts running, and the next step starts immediately. It does not block the job. wait and wait-all are the rendezvous. wait pins on one or more named background steps and pauses until they finish. wait-all is the same idea against every background step still in flight. Either way you get back into a linear flow on your terms. cancel is the cleanup. It gracefully terminates a background step when you no longer need it, which is the missing piece if you have ever tried to kill a long-running side process from inside a job and ended up shelling out to kill . parallel is the convenience wrapper. The changelog describes it as taking a group of steps and converting them into background steps with a wait placed after. For the common "fan out, then join" shape, you write one block instead of decorating five steps by hand. Where