Exit plan on first failed task

[rtyler]

❯ RUST_LOG=info ./target/debug/zap plan examples/basic.zplan -t bsd
Running plan with: PlanOpts { plan: "examples/basic.zplan", targets: "bsd", dry_run: false }
 ERROR zap_model::plan > Failed to parse task: Error { variant: CustomError { message: "No such file or directory (os error 2)" }, location: Pos(0), line_col: Pos((1, 1)), path: None, line: "", continued_line: None }
 ERROR zap_model::plan > Failed to parse task: Error { variant: CustomError { message: "No such file or directory (os error 2)" }, location: Pos(0), line_col: Pos((1, 1)), path: None, line: "", continued_line: None }
 ERROR zap_model::plan > Failed to parse task: Error { variant: CustomError { message: "No such file or directory (os error 2)" }, location: Pos(0), line_col: Pos((1, 1)), path: None, line: "", continued_line: None }
 INFO  zap             > Plan located, preparing to execute

Basically after that first one zap should bail

[ssimontis]

Does there need to be some sort of "grace" to the exit? Like any errors reported from the task, the machine on which the plan failed, count of tasks executed vs remaining, etc?

And should a failure on one host cause all hosts to stop their work, or should other hosts attempt to continue forward and attempt the same step?

[rtyler]

@ssimontis reporting errors and the target that failed is a good idea. I intend to eventually make the plan command run against targets in parallel, so I think at most the failures of a task should/could only exit out of the plan execution for the target which fails.