Summary
Docker inspect and less
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 post might also interest you.
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:
In this example, we will use jq to view the data returned by the inpect command.
docker inspect 4c45aea49180 | jq '.[].NetworkSettings.Networks'
Here is the result you will get.
{
"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
In this one we will get the arguments
docker inspect 4c45aea49180 | jq '.[].Args'
You get these results :
[
"-server",
"-advertise",
"192.168.99.100",
"-bootstrap-expect",
"1"
]
Get all the mounted volumes
[
{
"Name": "a8125ffdf6c4be1db4464345ba36b0417a18aaa3a025267596e292249ca4391f",
"Source": "/mnt/sda1/var/lib/docker/volumes/a8125ffdf6c4be1db4464345ba36b0417a18aaa3a025267596e292249ca4391f/_data",
"Destination": "/data",
"Driver": "local",
"Mode": "",
"RW": true
}
]
Conclusion
As you can see, jq simplifes a lot the viewing of your json data. No more scrolling through large json.
Not only for docker, it works with other tools like Marathon, Mesos, Consul etc.
More information can be found here: https://stedolan.github.io/jq/
