JOP (Journal of Operations)

Logs in memory, spatially and temporally, key value events.

These events, generated by multiple processes, are then flushed to disk for analysis (e.g. to detect locks).

Usage

  iex> "myjop"
  ...> |> Jop.init()
  ...> |> Jop.log("key_1", :any_term_112)
  ...> |> Jop.log("key_2", :any_term_133)
  ...> |> Jop.flush()
log stored in jop_myjop.2020_05_12_21.42.49_dates.gz
log stored in jop_myjop.2020_05_12_21.42.49_keys.gz
#Jop<myjop:uninitialized>

Basic example

# prepare for logging and return a handle
myjop = Jop.init("myjop")

# log with handle event "key_1", :any_term_112
Jop.log myjop, "key_1", :any_term_112
Process.sleep 12

# clear logs
Jop.clear myjop

Jop.log myjop, "key_2", :any_term_113
Process.sleep 12

Jop.log myjop, "key_1", :any_term_112
Process.sleep 12

Jop.log myjop, "key_2", :any_term_113
# flush to disk and erase the log
Jop.flush myjop

log stored in jop_myjop.2020_05_12_21.42.49_dates.gz
log stored in jop_myjop.2020_05_12_21.42.49_keys.gz
#Jop<myjop:uninitialized>

will generate both a temporal (by date) and a spatial (by key) log files:

Examining the temporal log file

# list all operations by date
zcat jop_myjop.2020_05_12_21.42.49_dates.gz

00:00:00_000.482 "key_2": :any_term_113
00:00:00_014.674 "key_1": :any_term_112
00:00:00_028.568 "key_2": :any_term_113

Examining the spatial (by key) log file

# list all operations by key :
zcat jop_myjop.2020_05_12_21.42.49_keys.gz

"key_1": 00:00:00_014.674 :any_term_112
"key_2": 00:00:00_000.482 :any_term_113
"key_2": 00:00:00_028.568 :any_term_113

Real life: concurrent process logging

Processes log in myjop as follow:

# Handle can be saved in process state
myjop = Jop.ref("myjop")

# Log if logging is activated
Jop.log myjop, "key_1", :any_term_112

Console activate / deactivate the logging:

# Activate the logging
# Starts the logging
myjop = Jop.init("myjop")

# Do some queries while the logging is on
inspect myjop # see how many records
Enum.count mylog
Enum.member? mylog, "mykey"
 ...

# Flush the logs on disk, keep on logging
Jop.flush myjop, :nostop

# Clear the logs, keep on logging
Jop.clear myjop  # clear all entries and continue logging

# Flush the logs on disk and deactivate the logging
Jop.flush myjop

# Start logging again
Jop.init("myjop")

Installation

Add jop to your list of dependencies in mix.exs:

def deps do
  [
    {:jop, "~> 0.1"}
  ]
end

Performance

Excerpt from a run of the unit test :

throughput 840812 logs/s. (1 process)
throughput 3851427 logs/s. (concurrency: 8 cores)