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5th chunk of `content/reference/api/registry/auth.md`
5c49ce0cd58841a435595f9af0fc8dff54bee3e11c9f14de0000000100000c5e
no attempt was made to authenticate), the token server must next query its
access control list to determine whether the client has the requested scope. In
this example request, if I have authenticated as user `jlhawn`, the token
server will determine what access I have to the repository `samalba/my-app`
hosted by the entity `registry.docker.io`.

Once the token server has determined what access the client has to the
resources requested in the `scope` parameter, it will take the intersection of
the set of requested actions on each resource and the set of actions that the
client has in fact been granted. If the client only has a subset of the
requested access **it must not be considered an error** as it is not the
responsibility of the token server to indicate authorization errors as part of
this workflow.

Continuing with the example request, the token server will find that the
client's set of granted access to the repository is `[pull, push]` which when
intersected with the requested access `[pull, push]` yields an equal set. If
the granted access set was found only to be `[pull]` then the intersected set
would only be `[pull]`. If the client has no access to the repository then the
intersected set would be empty, `[]`.

It is this intersected set of access which is placed in the returned token.

The server then constructs an implementation-specific token with this
intersected set of access, and returns it to the Docker client to use to
authenticate to the audience service (within the indicated window of time):

```text
HTTP/1.1 200 OK
Content-Type: application/json

{"token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NiIsImtpZCI6IlBZWU86VEVXVTpWN0pIOjI2SlY6QVFUWjpMSkMzOlNYVko6WEdIQTozNEYyOjJMQVE6WlJNSzpaN1E2In0.eyJpc3MiOiJhdXRoLmRvY2tlci5jb20iLCJzdWIiOiJqbGhhd24iLCJhdWQiOiJyZWdpc3RyeS5kb2NrZXIuY29tIiwiZXhwIjoxNDE1Mzg3MzE1LCJuYmYiOjE0MTUzODcwMTUsImlhdCI6MTQxNTM4NzAxNSwianRpIjoidFlKQ08xYzZjbnl5N2tBbjBjN3JLUGdiVjFIMWJGd3MiLCJhY2Nlc3MiOlt7InR5cGUiOiJyZXBvc2l0b3J5IiwibmFtZSI6InNhbWFsYmEvbXktYXBwIiwiYWN0aW9ucyI6WyJwdXNoIl19XX0.QhflHPfbd6eVF4lM9bwYpFZIV0PfikbyXuLx959ykRTBpe3CYnzs6YBK8FToVb5R47920PVLrh8zuLzdCr9t3w", "expires_in": 3600,"issued_at": "2009-11-10T23:00:00Z"}
```

## Using the Bearer token

Once the client has a token, it will try the registry request again with the
token placed in the HTTP `Authorization` header like so:

```text
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NiIsImtpZCI6IkJWM0Q6MkFWWjpVQjVaOktJQVA6SU5QTDo1RU42Ok40SjQ6Nk1XTzpEUktFOkJWUUs6M0ZKTDpQT1RMIn0.eyJpc3MiOiJhdXRoLmRvY2tlci5jb20iLCJzdWIiOiJCQ0NZOk9VNlo6UUVKNTpXTjJDOjJBVkM6WTdZRDpBM0xZOjQ1VVc6NE9HRDpLQUxMOkNOSjU6NUlVTCIsImF1ZCI6InJlZ2lzdHJ5LmRvY2tlci5jb20iLCJleHAiOjE0MTUzODczMTUsIm5iZiI6MTQxNTM4NzAxNSwiaWF0IjoxNDE1Mzg3MDE1LCJqdGkiOiJ0WUpDTzFjNmNueXk3a0FuMGM3cktQZ2JWMUgxYkZ3cyIsInNjb3BlIjoiamxoYXduOnJlcG9zaXRvcnk6c2FtYWxiYS9teS1hcHA6cHVzaCxwdWxsIGpsaGF3bjpuYW1lc3BhY2U6c2FtYWxiYTpwdWxsIn0.Y3zZSwaZPqy4y9oRBVRImZyv3m_S9XDHF1tWwN7mL52C_IiA73SJkWVNsvNqpJIn5h7A2F8biv_S2ppQ1lgkbw
```

This is also described in [Section 2.1 of RFC 6750: The OAuth 2.0 Authorization Framework: Bearer Token Usage](https://tools.ietf.org/html/rfc6750#section-2.1)

Title: Token Construction, Usage, and Bearer Token Implementation
Summary
The token server constructs a token with the intersected set of access and returns it to the Docker client. The client then retries the registry request with the token in the HTTP 'Authorization' header as a Bearer token, in accordance with RFC 6750.