[Feature]: Handling of concurrent connections to DataStorage

[averissimo]

Guidelines

• I agree to follow this project's Contributing Guidelines.

Description

TODO in the short term:

• documentation update to reflect this limitation

Add support for concurrent connections in DataStorage backends

In particular, DataStorageLogFile and DataStorageSQLite don't have any mecanism such as file lock.

This might degrade the performance of those backends, which can be counter-acted with implementing #148 to mitigate any impact.

Problem

library(parallel)

log_file <- shiny.telemetry::DataStorageLogFile$new("log_file.txt") # corrupt log file
log_file <- shiny.telemetry::DataStorageSQLite$new("log_db.sqlite") # fails to insert with "Error : database is locked"

log_file$insert(app_name = "yada", session = "fake", type = "text", details = "First write")

mclapply(
  seq(10000),
  \(.x) {
#    log_file <- shiny.telemetry::DataStoragePostgreSQL$new(user = "postgres", password = "mysecretpassword")
    log_file$insert(app_name = "yada", session = "fake", type = "text", details = "I 💙 shiny.telemetry")
#    log_file$close()
  },
  mc.cores = getOption("mc.cores", 8)
)

log_file$read_event_data()

Proposed Solution

• for ...LogFile: filelock
• for ...SQLite: TBD

Alternatives Considered

TBD