How to check if a Docker image with a specific tag exist locally?
Try docker inspect
, for example:
$ docker inspect --type=image treeder/hello.rb:nada
Error: No such image: treeder/hello.rb:nada
[]
But now with an image that exists, you'll get a bunch of information, eg:
$ docker inspect --type=image treeder/hello.rb:latest
[
{
"Id": "85c5116a2835521de2c52f10ab5dda0ff002a4a12aa476c141aace9bc67f43ad",
"Parent": "ecf63f5eb5e89e5974875da3998d72abc0d3d0e4ae2354887fffba037b356ad5",
"Comment": "",
"Created": "2015-09-23T22:06:38.86684783Z",
...
}
]
And it's in a nice json format.
tldr:
docker image inspect myimage:mytag
By way of demonstration...
success, found image:
$ docker image pull busybox:latest
latest: Pulling from library/busybox
Digest: sha256:32f093055929dbc23dec4d03e09dfe971f5973a9ca5cf059cbfb644c206aa83f
Status: Image is up to date for busybox:latest
$ docker image inspect busybox:latest >/dev/null 2>&1 && echo yes || echo no
yes
failure, missing image:
$ docker image rm busybox:latest
Untagged: busybox:latest
Untagged: busybox@sha256:32f093055929dbc23dec4d03e09dfe971f5973a9ca5cf059cbfb644c206aa83f
$ docker image inspect busybox:latest >/dev/null 2>&1 && echo yes || echo no
no
Reference:
https://docs.docker.com/engine/reference/commandline/image_inspect/
I usually test the result of docker images -q
(as in this script):
if [[ "$(docker images -q myimage:mytag 2> /dev/null)" == "" ]]; then
# do something
fi
But since .docker images
only takes REPOSITORY
as parameter, you would need to grep on tag, without using -q
docker images
takes tags now (docker 1.8+) [REPOSITORY[:TAG]]
The other approach mentioned below is to use docker inspect.
But with docker 17+, the syntax for images is: docker image inspect
(on an non-existent image, the exit status will be non-0)
As noted by iTayb in the comments:
- The
docker images -q
method can get really slow on a machine with lots of images. It takes 44s to run on a 6,500 images machine. - The
docker image inspect
returns immediately.
As noted in the comments by Henry Blyth:
If you use
docker image inspect my_image:my_tag
, and you want to ignore the output, you can add--format="ignore me"
and it will print that literally.You can also redirect stdout by adding
>/dev/null
but, if you can't do that in your script, then the format option works cleanly.