cmd: Add clients list command

[sawadashota]

Related issue

#1310

Proposed changes

Add hydra clients list command.
In this PR, command renders columns only client_id, name, response type, scope, RedirectUris, GrantTypes, TokenEndpointAuthMethod.

The command behaves like following.

$ go run main.go clients list --help
This command list an OAuth 2.0 Clients.

Example:
  hydra clients list

Usage:
  hydra clients list [flags]

Flags:
  -h, --help        help for list
      --limit int   The maximum amount of policies returned. (default 20)
      --page int    The number of page. (default 1)

Global Flags:
      --access-token string    Set an access token to be used in the Authorization header, defaults to environment variable OAUTH2_ACCESS_TOKEN
      --endpoint string        Set the URL where ORY Hydra is hosted, defaults to environment variable HYDRA_ADMIN_URL
      --fake-tls-termination   Fake tls termination by adding "X-Forwarded-Proto: https" to http headers
      --skip-tls-verify        Foolishly accept TLS certificates signed by unkown certificate authorities

$ go run main.go clients list --endpoint 'http://localhost:4445'
|              CLIENT ID               |   NAME    | RESPONSE TYPES |        SCOPE         |         REDIRECT URIS         |    GRANT TYPES     | TOKEN ENDPOINT AUTH METHOD |
|--------------------------------------|-----------|----------------|----------------------|-------------------------------|--------------------|----------------------------|
| b56de81b-5851-41e3-85ba-092883b094b1 | example3  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| be7047ff-bf38-4041-8ed5-652d0190b97d | example4  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| decf2324-2236-48b1-b3df-c55c3787877b | example8  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 1a02a217-6b67-4e17-b58f-8da04ca9a3ca | example12 | id_token,code  | openid profile email | https://example.com/callback  | authorization_code | none                       |
|                                      |           |                |                      | https://example.com/callback2 |                    |                            |
| 644df9cc-3f96-4898-b051-0e46c2d15d5d | example   | id_token,code  | openid profile email | https://example.com/callback  | authorization_code | none                       |
| ff99c49a-32b4-4532-9e90-dc044074c95e | example2  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| f94bc770-e8fe-4b90-8df4-38459c202f43 | example5  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 4c6dc0cd-de22-44f7-b658-eb30e1740f37 | example6  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 1fd91b28-36dc-4619-baa2-98f34d8c9273 | example7  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 2f84958e-b00d-46bc-b68b-9596f8e311c5 | example9  | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 51528e84-bcad-429f-9a22-561d53f7c1f2 | example10 | token          | hoge                 |                               | client_credentials | client_secret_basic        |
| 401fd0ab-89fd-41c7-bff4-6c58d79cf724 | example11 | token          | hoge                 |                               | client_credentials | client_secret_basic        |

$ go run main.go clients list --endpoint 'http://localhost:4445' --limit 2 --page 1
|              CLIENT ID               |   NAME   | RESPONSE TYPES |        SCOPE         |        REDIRECT URIS         |    GRANT TYPES     | TOKEN ENDPOINT AUTH METHOD |
|--------------------------------------|----------|----------------|----------------------|------------------------------|--------------------|----------------------------|
| 644df9cc-3f96-4898-b051-0e46c2d15d5d | example  | id_token,code  | openid profile email | https://example.com/callback | authorization_code | none                       |
| ff99c49a-32b4-4532-9e90-dc044074c95e | example2 | token          | hoge                 |                              | client_credentials | client_secret_basic        |

$ go run main.go clients list --endpoint 'http://localhost:4445' --limit 2 --page 2
|              CLIENT ID               |   NAME   | RESPONSE TYPES | SCOPE | REDIRECT URIS |    GRANT TYPES     | TOKEN ENDPOINT AUTH METHOD |
|--------------------------------------|----------|----------------|-------|---------------|--------------------|----------------------------|
| b56de81b-5851-41e3-85ba-092883b094b1 | example3 | token          | hoge  |               | client_credentials | client_secret_basic        |
| be7047ff-bf38-4041-8ed5-652d0190b97d | example4 | token          | hoge  |               | client_credentials | client_secret_basic        |

Checklist

• I have read the contributing guidelines
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact hi@ory.sh) from the maintainers to push the changes.
• I signed the Developer's Certificate of Origin
  by signing my commit(s). You can amend your signature to the most recent commit by using git commit --amend -s. If you
  amend the commit, you might need to force push using git push --force HEAD:<branch>. Please be very careful when using
  force push.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

Further comments

To render table, added following package.
https://github.com/olekukonko/tablewriter

[aeneasr]

Awesome changes! Just some nitpicks, then this can get merged!

[aeneasr]

Let's rename this to ListClients :)

[sawadashota]

Oops... I fixed!

[aeneasr]

Response Type should be Response Types. I also think it would be important to add the following fields:

• RedirectUris
• GrantTypes
• TokenEndpointAuthMethod

[sawadashota]

Exactly! Have added :)

[aeneasr]

Awesome, thank you!