concurrency

README

Includes golang concurrency design patterns and best practices:

• Golang concurrency architecture such as pipeline, fan in/out, race-to-finish.
• Go routine lifetime control with self cancelling go routines or external signals to complete go routines.
• Returning error from Go routines though context or error channels.
• Benchmarking to demonstrate the effective go routine spin, limiting number of workers to achieve execution speed, analysing performance bottlenecks.

simple concurrency with go routines:

• 2/2 simple go routine to handle connections concurrently
• 1/2 limit the number of connections

go routine lifetime

• 1/2 go routine signalling finish
• /2 waiting for go routines
• 2/2 cancelling go routines
• 1/2 returning error from go routines
• 3/3 timeout from go routine ( extra )
• 1/3 context timeout (extra)

benchmarking

• /3 benchmarking with go routines
• /3 execution of a task with concurrency vs single thread of execution comparison
• /2 stack growth of go routines
• /5 garbage collection and go routines
• /5 channel buffering for fast execution
• /5 limiting number of go routines executing concurrently

architectures ( channels & go routines )

• 1/1 pipeline
• 1/1 select statement and infinite loop
• 2/2 limiting number of workers ( extra )

/37 total + /13 extra points that can be added concurrency

@todo: time.After in case statement, stack growth ( downsides of using time.After in case statement ) @todo: release semaphores as a FILO manner

Directory structure and files

.
├── handleconn                  # handle incoming connections
|   ├── example1                # read/write n bytes at a time, should better handle the read/write buffering
|   ├── example2                # improves example 1 by using bufio to read/write, fixed the issue with writing more than necessary bytes, logs when closing connection
|   ├── example3                # uses io.Copy
|   ├── example4                # limit number of connections
├── architecture                #
|   ├── simplepipeline          # a barebone pipeline demonstrator
|   ├── simplepipeline2         # cancel go routines
|   ├── limitedworkers          # limited workers
|   ├── workersrace             # multiple workers working on same task, first to finish wins
├── lifetime                    # 
|   ├── closuretimeout          # simple query to dB with timeout packed in closure
|   ├── internaltimeout         # forselect loop that times out
|   ├── externaltimeout         # external channel signals timeout
|   ├── exitgoroutines          # exit with exit channel closure broadcast
|   ├── returnerror             # 
|   ├── contexttimeout          # timeout if context expires
|   ├── contextcancel           # go routine cancelled by another go routine
├── README.md                   # this file