Start up time of "exec" is slow

[joehoyle]

Start up time of "exec" is slow

[joehoyle]

Time to get to run the command on the CLI via composer (aka the composer wrapper command start-up time): 0.7s

cd vendor/altis/local-server/docker; VOLUME=/Users/joe/altis/dev COMPOSE_PROJECT_NAME=dev docker-compose exec -e COLUMNS=178 -e LINES=48  -u nobody php  whoami
real	0m0.719s
user	0m0.345s
sys	0m0.218s

[joehoyle]

Time to run the actual command:

time VOLUME=/Users/joe/altis/dev COMPOSE_PROJECT_NAME=dev docker-compose exec -e COLUMNS=178 -e LINES=48  -u nobody php  whoami
nobody

real	0m3.814s
user	0m0.577s
sys	0m0.194s

[joehoyle]

Running directly via docker exec is a lot faster:

time docker exec -u nobody 286ccd809caa whoami
nobody

real	0m0.265s
user	0m0.043s
sys	0m0.022s

[joehoyle]

It seems from docker/compose#4748 there is significant overhead to bootup docker-compose, see:

time docker-compose version
docker-compose version 1.24.1, build 4667896b
docker-py version: 3.7.3
CPython version: 3.6.8
OpenSSL version: OpenSSL 1.1.0j  20 Nov 2018

real	0m2.864s
user	0m0.450s
sys	0m0.168s