How can I find a Docker image with a specific tag in Docker registry on the Docker command line?
DockerDocker ImageDocker TagDocker Problem Overview
I try to locate one specific tag for a Docker image. How can I do it on the command line? I want to avoid downloading all the images and then removing the unneeded ones.
In the official Ubuntu release, https://registry.hub.docker.com/_/ubuntu/, there are several tags (release for it), while when I search it on the command line,
user@ubuntu:~$ docker search ubuntu | grep ^ubuntu
ubuntu Official Ubuntu base image 354
ubuntu-upstart Upstart is an event-based replacement for ... 7
ubuntufan/ping 0
ubuntu-debootstrap 0
Also in the help of command line search
https://docs.docker.com/engine/reference/commandline/search/, no clue how it can work?
Is it possible in the docker search
command?
If I use a raw command to search via the Docker registry API, then the information can be fetched:
$ curl https://registry.hub.docker.com//v1/repositories/ubuntu/tags | python -mjson.tool
[
{
"layer": "ef83896b",
"name": "latest"
},
.....
{
"layer": "463ff6be",
"name": "raring"
},
{
"layer": "195eb90b",
"name": "saucy"
},
{
"layer": "ef83896b",
"name": "trusty"
}
]
Docker Solutions
Solution 1 - Docker
When using CoreOS, jq
is available to parse JSON data.
So like you were doing before, looking at library/centos
:
$ curl -s -S 'https://registry.hub.docker.com/v2/repositories/library/centos/tags/' | jq '."results"[]["name"]' |sort
"6"
"6.7"
"centos5"
"centos5.11"
"centos6"
"centos6.6"
"centos6.7"
"centos7.0.1406"
"centos7.1.1503"
"latest"
The cleaner v2 API is available now, and that's what I'm using in the example. I will build a simple script docker_remote_tags
:
#!/usr/bin/bash
curl -s -S "https://registry.hub.docker.com/v2/repositories/library/$@/tags/" | jq '."results"[]["name"]' |sort
Enables:
$ ./docker_remote_tags library/centos
"6"
"6.7"
"centos5"
"centos5.11"
"centos6"
"centos6.6"
"centos6.7"
"centos7.0.1406"
"centos7.1.1503"
"latest"
Reference:
jq
: https://stedolan.github.io/jq/ | apt-get install jq
Solution 2 - Docker
I didn't like any of the solutions above because A) they required external libraries that I didn't have and didn't want to install. B) I didn't get all the pages.
The Docker API limits you to 100 items per request. This will loop over each "next" item and get them all (for Python it's seven pages; other may be more or less... It depends)
If you really want to spam yourself, remove | cut -d '-' -f 1
from the last line, and you will see absolutely everything.
url=https://registry.hub.docker.com/v2/repositories/library/redis/tags/?page_size=100 `# Initial url` ; \
( \
while [ ! -z $url ]; do `# Keep looping until the variable url is empty` \
>&2 echo -n "." `# Every iteration of the loop prints out a single dot to show progress as it got through all the pages (this is inline dot)` ; \
content=$(curl -s $url | python -c 'import sys, json; data = json.load(sys.stdin); print(data.get("next", "") or ""); print("\n".join([x["name"] for x in data["results"]]))') `# Curl the URL and pipe the output to Python. Python will parse the JSON and print the very first line as the next URL (it will leave it blank if there are no more pages) then continue to loop over the results extracting only the name; all will be stored in a variable called content` ; \
url=$(echo "$content" | head -n 1) `# Let's get the first line of content which contains the next URL for the loop to continue` ; \
echo "$content" | tail -n +2 `# Print the content without the first line (yes +2 is counter intuitive)` ; \
done; \
>&2 echo `# Finally break the line of dots` ; \
) | cut -d '-' -f 1 | sort --version-sort | uniq;
Sample output:
$ url=https://registry.hub.docker.com/v2/repositories/library/redis/tags/?page_size=100 `#initial url` ; \
> ( \
> while [ ! -z $url ]; do `#Keep looping until the variable url is empty` \
> >&2 echo -n "." `#Every iteration of the loop prints out a single dot to show progress as it got through all the pages (this is inline dot)` ; \
> content=$(curl -s $url | python -c 'import sys, json; data = json.load(sys.stdin); print(data.get("next", "") or ""); print("\n".join([x["name"] for x in data["results"]]))') `# Curl the URL and pipe the JSON to Python. Python will parse the JSON and print the very first line as the next URL (it will leave it blank if there are no more pages) then continue to loop over the results extracting only the name; all will be store in a variable called content` ; \
> url=$(echo "$content" | head -n 1) `#Let's get the first line of content which contains the next URL for the loop to continue` ; \
> echo "$content" | tail -n +2 `#Print the content with out the first line (yes +2 is counter intuitive)` ; \
> done; \
> >&2 echo `#Finally break the line of dots` ; \
> ) | cut -d '-' -f 1 | sort --version-sort | uniq;
...
2
2.6
2.6.17
2.8
2.8.6
2.8.7
2.8.8
2.8.9
2.8.10
2.8.11
2.8.12
2.8.13
2.8.14
2.8.15
2.8.16
2.8.17
2.8.18
2.8.19
2.8.20
2.8.21
2.8.22
2.8.23
3
3.0
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.0.6
3.0.7
3.0.504
3.2
3.2.0
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.2.7
3.2.8
3.2.9
3.2.10
3.2.11
3.2.100
4
4.0
4.0.0
4.0.1
4.0.2
4.0.4
4.0.5
4.0.6
4.0.7
4.0.8
32bit
alpine
latest
nanoserver
windowsservercore
If you want the bash_profile
version:
function docker-tags () {
name=$1
# Initial URL
url=https://registry.hub.docker.com/v2/repositories/library/$name/tags/?page_size=100
(
# Keep looping until the variable URL is empty
while [ ! -z $url ]; do
# Every iteration of the loop prints out a single dot to show progress as it got through all the pages (this is inline dot)
>&2 echo -n "."
# Curl the URL and pipe the output to Python. Python will parse the JSON and print the very first line as the next URL (it will leave it blank if there are no more pages)
# then continue to loop over the results extracting only the name; all will be stored in a variable called content
content=$(curl -s $url | python -c 'import sys, json; data = json.load(sys.stdin); print(data.get("next", "") or ""); print("\n".join([x["name"] for x in data["results"]]))')
# Let's get the first line of content which contains the next URL for the loop to continue
url=$(echo "$content" | head -n 1)
# Print the content without the first line (yes +2 is counter intuitive)
echo "$content" | tail -n +2
done;
# Finally break the line of dots
>&2 echo
) | cut -d '-' -f 1 | sort --version-sort | uniq;
}
And simply call it: docker-tags redis
Sample output:
$ docker-tags redis
...
2
2.6
2.6.17
2.8
--trunc----
32bit
alpine
latest
nanoserver
windowsservercore
Solution 3 - Docker
As far as I know, the CLI does not allow searching/listing tags in a repository.
But if you know which tag you want, you can pull that explicitly by adding a colon and the image name: docker pull ubuntu:saucy
Solution 4 - Docker
This script (docker-show-repo-tags.sh) should work for any Docker enabled host that has curl, sed, grep, and sort. This was updated to reflect the fact the repository tag URLs changed.
#!/bin/sh
#
# Simple script that will display Docker repository tags
# using basic tools: curl, sed, grep, and sort.
#
# Usage:
# $ docker-show-repo-tags.sh ubuntu centos
for Repo in $* ; do
curl -sS "https://hub.docker.com/r/library/$Repo/tags/" | \
sed -e $'s/"tags":/\\\n"tags":/g' -e $'s/\]/\\\n\]/g' | \
grep '^"tags"' | \
grep '"library"' | \
sed -e $'s/,/,\\\n/g' -e 's/,//g' -e 's/"//g' | \
grep -v 'library:' | \
sort -fu | \
sed -e "s/^/${Repo}:/"
done
This older version no longer works.
#!/bin/sh
# WARNING: This no long works!
# Simple script that will display Docker repository tags.
#
# Usage:
# $ docker-show-repo-tags.sh ubuntu centos
for Repo in $* ; do
curl -s -S "https://registry.hub.docker.com/v2/repositories/library/$Repo/tags/" | \
sed -e $'s/,/,\\\n/g' -e $'s/\[/\\\[\n/g' | \
grep '"name"' | \
awk -F\" '{print $4;}' | \
sort -fu | \
sed -e "s/^/${Repo}:/"
done
This is the output for a simple example:
$ docker-show-repo-tags.sh centos | cat -n
1 centos:5
2 centos:5.11
3 centos:6
4 centos:6.10
5 centos:6.6
6 centos:6.7
7 centos:6.8
8 centos:6.9
9 centos:7.0.1406
10 centos:7.1.1503
11 centos:7.2.1511
12 centos:7.3.1611
13 centos:7.4.1708
14 centos:7.5.1804
15 centos:centos5
16 centos:centos5.11
17 centos:centos6
18 centos:centos6.10
19 centos:centos6.6
20 centos:centos6.7
21 centos:centos6.8
22 centos:centos6.9
23 centos:centos7
24 centos:centos7.0.1406
25 centos:centos7.1.1503
26 centos:centos7.2.1511
27 centos:centos7.3.1611
28 centos:centos7.4.1708
29 centos:centos7.5.1804
30 centos:latest
Solution 5 - Docker
I wrote a command line tool to simplify searching Docker Hub repository tags, available in my PyTools GitHub repository. It's simple to use with various command line switches, but most basically:
./dockerhub_show_tags.py repo1 repo2
It's even available as a Docker image and can take multiple repositories:
docker run harisekhon/pytools dockerhub_show_tags.py centos ubuntu
DockerHub
repo: centos
tags: 5.11
6.6
6.7
7.0.1406
7.1.1503
centos5.11
centos6.6
centos6.7
centos7.0.1406
centos7.1.1503
repo: ubuntu
tags: latest
14.04
15.10
16.04
trusty
trusty-20160503.1
wily
wily-20160503
xenial
xenial-20160503
If you want to embed it in scripts, use -q
/ --quiet
to get just the tags, like normal Docker commands:
./dockerhub_show_tags.py centos -q
5.11
6.6
6.7
7.0.1406
7.1.1503
centos5.11
centos6.6
centos6.7
centos7.0.1406
centos7.1.1503
Solution 6 - Docker
The v2 API seems to use some kind of pagination, so that it does not return all the available tags. This is clearly visible in projects such as python
(or library/python
). Even after quickly reading the documentation, I could not manage to work with the API correctly (maybe it is the wrong documentation).
Then I rewrote the script using the v1 API, and it is still using jq
:
#!/bin/bash
repo="$1"
if [[ "${repo}" != */* ]]; then
repo="library/${repo}"
fi
url="https://registry.hub.docker.com/v1/repositories/${repo}/tags"
curl -s -S "${url}" | jq '.[]["name"]' | sed 's/^"\(.*\)"$/\1/' | sort
The full script is available at: <https://github.com/denilsonsa/small_scripts/blob/master/docker_remote_tags.sh>
I've also written an improved version (in Python) that aggregates tags that point to the same version: <https://github.com/denilsonsa/small_scripts/blob/master/docker_remote_tags.py>
Solution 7 - Docker
Add this function to your .zshrc file or run the command manually:
#usage list-dh-tags <repo>
#example: list-dh-tags node
function list-dh-tags(){
wget -q https://registry.hub.docker.com/v1/repositories/$1/tags -O - | sed -e 's/[][]//g' -e 's/"//g' -e 's/ //g' | tr '}' '\n' | awk -F: '{print $3}'
}
Thanks to this -> https://stackoverflow.com/questions/28320134/how-to-list-all-tags-for-a-docker-image-on-a-remote-registry
Solution 8 - Docker
For anyone stumbling across this in modern times, you can use Skopeo to retrieve an image's tags from the Docker registry:
$ skopeo list-tags docker://jenkins/jenkins \
| jq -r '.Tags[] | select(. | contains("lts-alpine"))' \
| sort --version-sort --reverse
lts-alpine
2.277.3-lts-alpine
2.277.2-lts-alpine
2.277.1-lts-alpine
2.263.4-lts-alpine
2.263.3-lts-alpine
2.263.2-lts-alpine
2.263.1-lts-alpine
2.249.3-lts-alpine
2.249.2-lts-alpine
2.249.1-lts-alpine
2.235.5-lts-alpine
2.235.4-lts-alpine
2.235.3-lts-alpine
2.235.2-lts-alpine
2.235.1-lts-alpine
2.222.4-lts-alpine
Solution 9 - Docker
Reimplementation of the previous post, using Python over sed/AWK:
for Repo in $* ; do
tags=$(curl -s -S "https://registry.hub.docker.com/v2/repositories/library/$Repo/tags/")
python - <<EOF
import json
tags = [t['name'] for t in json.loads('''$tags''')['results']]
tags.sort()
for tag in tags:
print "{}:{}".format('$Repo', tag)
EOF
done
Solution 10 - Docker
For a script that works with OAuth bearer tokens on Docker Hub, try this:
Solution 11 - Docker
You can use Visual Studio Code to provide autocomplete for available Docker images and tags. However, this requires that you type the first letter of a tag in order to see autocomplete suggestions.
For example, when writing FROM ubuntu
it offers autocomplete suggestions like ubuntu
, ubuntu-debootstrap
and ubuntu-upstart
. When writing FROM ubuntu:a
it offers autocomplete suggestions, like ubuntu:artful
and ubuntu:artful-20170511.1