Docker Cookbook

Discussion
This short example uses the default setup of the registry. It assumes no authentica‐
tion, an insecure registry, local storage, and a SQLAlchemy search backend. All of
these can be set via environmental variables or by editing a configuration file. This is
well 
documented
.
The registry that is running via the 
registry
Docker image is a Golang application that
exposes an HTTP REST 
API
, and that you can access with your own registry client or
even 
curl
.
For example, to list all images stored in the private registry, you can use the 
/v2/_cata‐
log
URI:
$ curl http://localhost:5000/v2/_catalog
{"repositories":["busy"]}
If you push another 
busybox
image to the private registry but tagged differently, you
will see it being added to the catalog:
$ docker tag busybox localhost:5000/busy1
$ docker push localhost:5000/busy1
...
$ curl http://localhost:5000/v2/_catalog
{"repositories":["busy","busy1"]}
60 | Chapter 2: Image Creation and Sharing

---

Each image in the registry is described by a manifest. You can get this manifest via the
API as well at the 
/v2//manifests/
URI, where 

is the name
of the image and 

is a tag of the image:
$ curl http://localhost:5000/v2/busy1/manifests/latest
{
"schemaVersion": 1,
"name": "busy1",
"tag": "latest",
"architecture": "amd64",
"fsLayers": [
{
"blobSum": "sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d..."
},
{
"blobSum": "sha256:1db09adb5ddd7f1a07b6d585a7db747a51c7bd17418d47e..."
},
{
"blobSum": "sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d..."
}
],
...
Each 
blob
seen in the preceding code corresponds to a layer of the image. You can
upload, retrieve, and delete blobs through the registry API. Details are available in the
API specification documentation 
page
.
To list all tags for a specific image, use the 
v2//tags/list
URI like so:
$ curl http://localhost:5000/v2/busy1/tags/list
{"name":"busy1","tags":["latest"]}
$ docker tag busybox localhost:5000/busy1:foobar
$ docker push localhost:5000/busy1:foobar
$ curl http://localhost:5000/v2/busy1/tags/list
{"name":"busy1","tags":["foobar","latest"]}
These examples using 
curl
are meant to give you a sense of the registry API. Com‐
plete API documentation is available on the 
Docker website
.
See Also
• The Docker registry page on 
Docker Hub
• The more extensive documentation on 
GitHub
• Deployment 
instructions