Summary
Docker inspect and grep
This isn’t so much a docker tip, as it is a jq tip. If you haven’t heard of jq, it is a great tool for parsing JSON from the command line. This also makes it a great tool to see what is happening in a container instead of having to use the –format specifier which I can never remember how to use exactly:
# Get network information:
$ [docker](/blog/en/jenkins/how-to-run-jenkins-jobs-with-docker) inspect 4c45aea49180 | jq '.[].NetworkSettings.Networks'
{
"bridge": {
"EndpointID": "ba1b6efba16de99f260e0fa8892fd4685dbe2f79cba37ac0114195e9fad66075",
"Gateway": "172.17.0.1",
"IPAddress": "172.17.0.2",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:11:00:02"
}
}
# Get the arguments with which the [container](/blog/en/docker/3-ways-to-connect-your-dolibarr-container-to-local-database) was started
$ [docker](/blog/en/docker/how-to-setup-your-local-nodejs-development-environment-using-docker) inspect 4c45aea49180 | jq '.[].Args'
[
"-server",
"-advertise",
"192.168.99.100",
"-bootstrap-expect",
"1"
]
# Get all the mounted volumes
11:22 $ [docker](/blog/en/docker/what-is-difference-between-docker-attach-and-exec) inspect 4c45aea49180 | jq '.[].Mounts'
[
{
"Name": "a8125ffdf6c4be1db4464345ba36b0417a18aaa3a025267596e292249ca4391f",
"Source": "/mnt/sda1/var/lib/[docker](/blog/en/docker/how-do-i-connect-mysql-workbench-to-mysql-inside-docker)/volumes/a8125ffdf6c4be1db4464345ba36b0417a18aaa3a025267596e292249ca4391f/_data",
"Destination": "/data",
"Driver": "local",
"Mode": "",
"RW": true
}
]
And of course also works great for querying other kinds of (docker-esque) APIs that produce JSON (e.g Marathon, Mesos, Consul etc.). JQ provides a very extensive API for accessing and processing JSON. More information can be found here: https://stedolan.github.io/jq/
