Image showing Docker tip : inspect and grep

Docker tip : inspect and grep

affiliate best offer

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 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 was started

$ docker inspect 4c45aea49180 | jq '.[].Args'
[
"-server",
"-advertise",
"192.168.99.100",
"-bootstrap-expect",
"1"
]

# Get all the mounted volumes

11:22 $ docker inspect 4c45aea49180 | jq '.[].Mounts'
[
{
"Name": "a8125ffdf6c4be1db4464345ba36b0417a18aaa3a025267596e292249ca4391f",
"Source": "/mnt/sda1/var/lib/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/

You might also like these blog posts

Full Bright

Full Bright

A professional and sympathic business man.

Contact

Contact Us

To order one of our services, navigate to the order service page

Address

10 rue de Penthièvre,
75008 Paris

Email Us

hello at bright-softwares dot com

Open Hours

Monday - Friday
9:00AM - 05:00PM