logfile.update: Log data manipulation
In mvisalli/shipr: ships for whales functions

Description Usage Arguments Details Examples

logfile.update

logfile.update(
  log_df = NULL,
  url = NULL,
  is_read = FALSE,
  assign_back = FALSE,
  logfile_path = NULL,
  ...
)

`log_df`	The table/data.frame containing the log data
`url`	the url to either be updated or appended
`is_read`	logical indicating whether or not the url has already been read in
`assign_back`	logical indicating whether the data.frame should be reassigned back to the working environment
`logfile_path`	If provided and the log_df param is NULL, this file path will be processed into the working environment/function as the log_df. Upon exit, the new data will be written to the file location. At time of build/testing there is a logfile located at `inst/data/logfile.json`
`...`	additional arguments to be processed

This function handles the processing of our log data. The log data will tell our other functions what needs to be read, what has been read and where to start/stop. Additionally the time-stamps will provide a little insight into debugging if data is missing etc in the future.

You can import the log data from a database and pass to the log_df parameter, which if you then set assign_back to TRUE, will reassign the updated dataframe back into the work-space, and can be written back to the database after. See examples for a rough walk-through.

Additionally you can provide a path to a json file for processing. This will avoid the need to add any tables to the working environment, and will assign, in place the dataframe, and write to the same connection upon closing.

If a url already exists, but we are changing the status of the data being read, the data is updated in place, and the cell for is_read simply changes.

FOR DB connection

Create the object in R as the_log
the_log <- dbConnect(your_tables)

this will reassign the new data to the_log, note that if assign_back = FALSE,
the entire data.frame will be returned, so catch with the_log <- logfile.update(log_df = the_log)
logfile.update(log_df = the_log, assign_back = TRUE)

write back to db
writeDB(the_log, ...)

Example if the data is in the environment as log_df_test with only 4 rows
nrow(log_df)
[1] 4

> tail(log_df_test,1)
                                                                       url is_read  timestamp
4 https://ais.sbarc.org/logs_delimited/2018/180101/AIS_SBARC_180101-03.txt   FALSE 1574145802

> logfile.update(log_df = log_df_test, url = "testurl.com", is_read = TRUE, assign_back = TRUE)
> tail(log_df_test,2)
                                                                       url is_read  timestamp
4 https://ais.sbarc.org/logs_delimited/2018/180101/AIS_SBARC_180101-03.txt   FALSE 1574145802
5                                                              testurl.com    TRUE 1574148016

> nrow(log_df_test)
[1] 5