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Read checkpoint

Source: R/checkpoint.R
read_checkpoint.Rd

Reads a checkpoint by ID, or the latest valid checkpoint if ID is not specified. Verifies checksums before returning data.

Usage

read_checkpoint(result_path, checkpoint_id = NULL, load_outcomes = TRUE)

Arguments

result_path

Character string giving the base path for results. If NULL, the function returns NULL immediately.

checkpoint_id

Integer specifying the checkpoint ID to read. If NULL (default), reads the latest checkpoint from latest.json.

load_outcomes

Logical; when FALSE, validate shard integrity but omit materializing accumulated outcomes. Used by the filesystem RunStore while appending the next ledger checkpoint.

Value

A list with the following elements, or NULL if checkpoint not found or invalid:

  • checkpoint_id - Integer ID of the checkpoint

  • meta - List of checkpoint metadata

  • task_grid - Tibble/data.frame of task grid with status

  • results_df - Data frame of task results

Details

The function performs the following steps:

  1. If checkpoint_id is NULL, read latest.json to get the latest ID

  2. Construct checkpoint directory path from the ID

  3. Verify directory exists

  4. Verify checksums match

  5. Read meta.json, ledger.rds, and results.rds

  6. Return assembled checkpoint data

If the checkpoint has invalid checksums, a warning is issued and NULL is returned. This allows the caller to fall back to earlier checkpoints.

See also

write_checkpoint(), list_checkpoints(), validate_checkpoint_fingerprint()

Examples

if (FALSE) { # \dontrun{
# Read latest checkpoint
checkpoint <- read_checkpoint("/path/to/results")

# Read specific checkpoint
checkpoint <- read_checkpoint("/path/to/results", checkpoint_id = 5)
} # }