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Retry tasks

Source: R/rrq_retry.R
rrq_task_retry.Rd

Retry a task (or set of tasks). Typically this is after failure (e.g., ERROR, DIED or similar) but you can retry even successfully completed tasks. Once retried, functions that retrieve information about a task (e.g., rrq_task_status(), [rrq_task_result()]) will behave differently depending on the value of their followargument. Seevignette("fault-tolerance")` for more details.

Usage

rrq_task_retry(task_ids, controller = NULL)

Arguments

task_ids

Task ids to retry.

controller

The controller to use. If not given (or NULL) we'll use the controller registered with rrq_default_controller_set().

Value

New task ids

Examples

obj <- rrq_controller("rrq:example")

# It's straightforward to see the effect of retrying a task with
# one that produces a different value each time, so here, we use a
# simple task that draws one normally distributed random number
t1 <- rrq_task_create_expr(rnorm(1), controller = obj)
rrq_task_wait(t1, controller = obj)
#> [1] TRUE
rrq_task_result(t1, controller = obj)
#> [1] -0.6648678

# If we retry the task we'll get a different value:
t2 <- rrq_task_retry(t1, controller = obj)
rrq_task_wait(t2, controller = obj)
#> [1] TRUE
rrq_task_result(t2, controller = obj)
#> [1] 0.7877277

# Once a task is retried, most of the time (by default) you can use
# the original id and the new one exchangeably:
rrq_task_result(t1, controller = obj)
#> [1] 0.7877277
rrq_task_result(t2, controller = obj)
#> [1] 0.7877277

# Use the 'follow' argument to modify this behaviour
rrq_task_result(t1, follow = FALSE, controller = obj)
#> [1] -0.6648678
rrq_task_result(t2, follow = FALSE, controller = obj)
#> [1] 0.7877277

# See the retry chain with rrq_task_info
rrq_task_info(t1, controller = obj)
#> $id
#> [1] "d0b91033a5eac68ddf20c4b549f55eec"
#> 
#> $status
#> [1] "MOVED"
#> 
#> $queue
#> [1] "default"
#> 
#> $separate_process
#> [1] FALSE
#> 
#> $timeout
#> NULL
#> 
#> $worker
#> [1] "exhaustible_umbrette"
#> 
#> $pid
#> NULL
#> 
#> $depends
#> $depends$up
#> NULL
#> 
#> $depends$down
#> NULL
#> 
#> 
#> $moved
#> $moved$up
#> NULL
#> 
#> $moved$down
#> [1] "a48b72e80b66c2ce40fbb24c83a6536b"
#> 
#> 
rrq_task_info(t2, controller = obj)
#> $id
#> [1] "a48b72e80b66c2ce40fbb24c83a6536b"
#> 
#> $status
#> [1] "COMPLETE"
#> 
#> $queue
#> NULL
#> 
#> $separate_process
#> logical(0)
#> 
#> $timeout
#> NULL
#> 
#> $worker
#> [1] "exhaustible_umbrette"
#> 
#> $pid
#> NULL
#> 
#> $depends
#> $depends$up
#> NULL
#> 
#> $depends$down
#> NULL
#> 
#> 
#> $moved
#> $moved$up
#> [1] "d0b91033a5eac68ddf20c4b549f55eec"
#> 
#> $moved$down
#> NULL
#> 
#>