WikiPrint - from Polar Technologies

DETER Testbed API

The DETER testbed API is broken up into 5 services, each covering one of the major abstractions that the testbed exports. The services are:

We discuss each in detail and provide links to the detailed javadoc of the implementation, where applicable and available.

The document and API are both works in progress and will be fleshed out and changed as the API is modified.

General Info

The API is implemented as a SOAP web service over TLS secured connections. The user's identity is generally provided by a client certificate, but the client certificates are generally transient. A valid temporary client certificate can be requested from the API by correctly responding to a challenge keyed on the user's password.

The API is implemented using the axis web service framework, which means that javadocs are provided for the various calls.

Each service and call are accessed by appending servicename/operation to the base URL of the API server. On DETERlab the base URL will be ​https://api.isi.deterlabnet:52323/axis2/service. For example, one can access the getVersion operation below at ​https://api.isi.deterlabnet:52323/axis2/service/ApiInfo/getVersion

Each operation returns useful parameters on success and throws a fault, called a DeterFault, on an error. Faults are standard SOAP faults with a detail section that includes the following fields:

The ErrorString and ErrorCode are equivalent, but the information in the DetailString is generally more informative about the specifics. Request or access errors are generally correctable on the client side while internal errors are not.

​javadoc for DeterFault

ApiInfo

The ApiInfo service provides metadata about the running DETER API. It also provides a simple check that a user is presenting authentication credentials correctly.

​javadoc for ApiInfo

The primary operation in the ApiInfo service is getVersion. The call is unauthenticated and can be made driectly from a web browser to confirm that the API is functioning and that the user can see DETERlab.

There is an addtional simpler service, echo, that takes one parameter and returns it:

Users

The Users API is concerned with managing users and their profiles as well as authenticating to the testbed and receiving a client certificate for later calls.

​javadoc for Users

Authentication

A user can authenticate to the testbed and receive a short-lived client x.509 certificate by requesting a challenge using the requestChallenge operation and responding to the challenge via the challengeResponse operation.

Currently only one challenge is available, type "clear". The challenge has no data and the user replies with their password in clear text. Note that the exchange is protected by the SSL encrypted exchange, but implementors should not respond to clear challenges with parameters in the query string. The "masked" challenge will address this issue shortly.

Each challenge is valid for 2 minutes and are rate limited. Web interfaces should collect the password from the user before requesting a challenge from the API to avoid spurious timeouts.

The certificate returned by the challenge is signed by the testbed.

Password Changes

The password is a unique user feature that is not in the profile because of its role in authentication. When a user needs to change their password there are two API calls that can be used.

If the user knows their current (or expired) password, they can authenticate using the standard challenge response protocol and then call

We expect that the web interface will handle issues like confirming user input to a password change page. The changePassword call just makes the change directly.

If a user has forgotten their password, the user can request a password challenge, sent to them at their profile e-mail address. The challenge is a 64-bit number that can be used to call changePasswordChallenge without logging in. To request a challenge, the web interface calls:

Again, we expect this call to generally be made from a web interface that will then want to present an input form to the in order to reset their password. The urlPrefix field provides that hook. A web interface running on https://niftydeter.com might call requestPasswordReset with parameters 'forgetfuluser' and 'https://niftydeter.com/reset.html?challenge='. After that call forgetfuluser will get e-mail asking him or her to access the web page at https://niftydeter.com/reset.html?challenge=1283548127541824, allowing niftydeter.com to present their password change interface, and do error checking, ete. on the new password.

Each challenge is valid for 2 hours, and they are rate limited so only a few can be outstanding.

With a valid challenge in hand, the web interface can call

Profile Manipulation

DETER keeps metadata about each user called a profile. The API provides an authenticated user with several interfaces to query and modify their profile information.

In the API each element of profile data is represented as a structure with the following data in it:

To get a profile schema, for example to create an empty web page,

To read a user's profile (generally only users can read their own profile).

Finally a user can modify a profile:

Notifications

A notification is a short message from another user or the testbed asking a user to take an action (add someone to a project, update a password before expiration) or communicating other information to the user (testbed downtime, etc). A web interface will want to present these to a user.

Each notification has a set of flags that define its state. Currently there are 2

The user is free to change this state using the markNotifications call. Note that notifications are per-user. A user who clears the READ or URGENT bit does not clear the bit for other recipients of the notification.

The filtering variables are all applied if given.

The mask and flags variable define the state a user is searching for. If a bit is set in both mask and flags, only messages with that bit set are returned. Similarly if a bit is clear in flags and set in mask, only messages with that bit clear will be returned.

To be concrete: a user who wants to retrieve all unread messages (urgent or not) should send a flags field with the READ bit clear and a mask with the READ bit set. To retrieve only unread urgent messages, the flags should have READ clear and URGENT set, and both READ and URGENT set in the mask.

Administrators can send notifications, for example to announce testbed events. The call to do so is:

Creation and Deletion

Finally a user can request access to the testbed by creating a profile. The user has no privileges and consumes minimal resources until they join a vetted project. This is an unauthenticated call, but the user profile is not created until an automated e-mail exchange is made between the testbed and the proto-user.

Note that all non-optional fields must be provided, so this is best preceeded by a call to getProfileDescription to learn the fields.

A base userid is constructed, either from the userid presented or from a required field in the profile. If that base userid is available, that a user with that userid is created. Otherwise the userid is disambiguated until there are no collisions. The userid actually created is returned.

The user is created without membership in any projects and without a password. A password reset challenge (equivalent to one issued by requestPasswordReset) is issued and the challenge e-mailed to the user at the address in the profile.

Administrators can create users without the confirmation step:

Note that either the cleartext password or the hash and type must be passed. This interface is under for initializing the testbed or creating users in batch for something like a class.

Removing a user is accomplished using

Most users are unlikely to use this service, and policy may allow only administrators to remove users.

Manipulating Profile Attributes

Administrators may add attributes to user profiles or remove them. That is to say, add a schema (including format constraints and descriptions), not set a value for a user.

Creating an attribute:

And removing an attribute:

Finally administrators can modify profile attributes:

Projects

The profile API lets users manage their project memberships as well as manipulate projects.

Listing Projects

Authenticated users can look at the various projects they are members of, and may scope such searcher by project names.

Filters are cumulative: specifying a regular expression and an owner will match on both.

Changing Project Membership

Each of these changes propagates to the linked circle that controls resource permissions for the project. In particular, the permissions fields should include the union of the project and circle rights to set

With appropriate rights a user can add another user to a project they are in. The user being added must confirm this addition (below). As a result of this call, users being added will be sent a notification including a challenge id to respond to, similar to a password change URL. The prefix for that URL can be passed in here.

For each user successfully added, a notification is sent. To respond to that notification the UI must call:

Administrators can add users without going through the confirmation process:

Users can also request to join a project. This requires some member of the project with ADD_USER rights to agree, so a notification is sent to all such users.

The join succeeds when a user with appropriate permissions calls joinProjectConfirm. Note that the user calling joinProjectConfirm sets the new user's project permissions.

Users can be removed from projects:

If a user has the right to both add and remove a user, that user can change a user's permissions:

Manipulating Projects

The owner of a group (and only the owner of that group) can give that privilege away:

Project Profiles

The calls for manipulating a project profile are very similar to user profiles:

To get a profile schema, for example to create an empty web page,

To read a project's profile.

Finally a user can modify a project profile:

Manipulating Profile Attributes

Administrators may add attributes to project profiles or remove them. That is to say, add a schema (including format constraints and descriptions), not set a value for a project.

Creating an attribute:

And removing an attribute:

Finally administrators can modify profile attributes:

Creating and Deleting Projects

Creating and removing projects are also similar to creating and removing users:

As with users, all required (non-optional) fields in the profile must be provided. The project will be created, but have no rights until approved.

On success the new project is created with the calling user as owner and sole member. The user has all rights.

Approval is a result of the testbed's vetting process. The user will be sent a notification when their project is approved. When approved this call is made by an admin.

Note that this call can be used to un-approve a previously approved project.

Removing a project is straightforward

Generally an removing a project requires a testbed administrator.

Circles

The profile API lets users manage their circle memberships as well as manipulate circles. The circles API is similar to the Projects API. The primary exceptions are that there is no approval process for circles (though there is for joining or adding a user) and that the permissions are different.

These calls work on all circles except those linked to a project. Those circles must have their membership, ownership, and permissions manipulated through the project to ensure that the contents remain synchronized.

Listing Circles

Authenticated users can look at the various circles they are members of, and may scope such searcher by circle names.

Filters are cumulative: specifying a regular expression and an owner will match on both.

Changing Circle Membership

With appropriate rights a user can add another user to a circle they are in. The user being added must confirm this addition (below). As a result of this call, users being added will be sent a notification including a challenge id to respond to, similar to a password change URL. The prefix for that URL can be passed in here.

For each user successfully added, a notification is sent. To respond to that notification the UI must call:

Administrators can add users without going through the confirmation process:

Users can also request to join a circle. This requires some member of the circle with ADD_USER rights to agree, so a notification is sent to all such users.

The join succeeds when a user with appropriate permissions calls joinCircleConfirm. Note that the user calling joinCircleConfirm sets the new user's circle permissions.

Users can be removed from circles:

If a user has the right to both add and remove a user, that user can change a user's permissions:

Manipulating Circles

The owner of a group (and only the owner of that group) can give that privilege away to another member:

Circle Profiles

The calls for manipulating a circle profile are very similar to user profiles:

To get a profile schema, for example to create an empty web page,

To read a circle's profile.

Finally a user can modify a circle profile:

Manipulating Profile Attributes

Administrators may add attributes to circle profiles or remove them. That is to say, add a schema (including format constraints and descriptions), not set a value for a circle. Creating an attribute:

And removing an attribute:

Finally administrators can modify profile attributes:

Creating and Deleting Circles

Creating and removing circles are also similar to creating and removing users:

As with users, all required (non-optional) fields in the profile must be provided. The circle will be created, and can be used immediately.

Removing a circle is straightforward.

Experiments

The experiment interface controls managing experiment definitions and realizing experimnets (allocating and initializing resources). The experimnet definition is in some flux, which is reflected in this section.

Viewing Experiments

One or more experiments can be viewed by an authorized user assuming that user has the proper permissions. The creator of a project owns it and that userid scopes its name. That is an experiment's name is a pair: (owner, name). This allows experiments to be instantiated in different projects.

Creating and Deleting Experiments

An experiment is created using:

An experiment is modified using:

Omitted arguments are not overwritten. To delete a field supply an empty description.

There will also be filter-based modification interfaces, but these are TBD.

An experiment is deleted using:

After removeExperiment succeeds, experiment state is removed from the testbed completely.

Realizing and Releasing Experiments

To realize an experiment use:

The user can either poll the experiment using viewExperiments and examining the StateDetail field or poll for a notification that the realization is complete.

If the realization fails - as indicated by the State variable in a viewExperiments response, the Log and FaultInfo fields characterize the error.

To release an experiment's resources:

After releaseExperiment succeeds, experiment state remains in the testbed, but containers are stopped and resources are returned to the testbed.

Resources

Resources are things that make up experiments. There are several specialized resources used in experimentation that have their own suite of operations, and there is a general set of operations for future expansion.

Computers

Computers are the physical computing resources of the testbed. A user may be interested in specific instances of a computer - pc23 - or in information about types or classes of computers. Both are possible to view with these calls.

A user can view computers or classes by:

If any of the permission fields are not present, the class permissions apply. If they are present for a specific computer, they specific computer's permissions override the class permissions.

Administrators can add new computers or classes using

Note that missing fields in a computer creation are generally filled in from the type. Creating a computer or class without any projects that can use it is of questionable value.

Similarly, they can modify an existing computer using (assuming they are in a project that allows modification of the class or computer):

Values passed in overwrite the current values if the user had modify rights. One of Name or Type must be present.

Finally an administrator can delete a computer:

Images

Images are saved container state - including saved physical container state. These are selected in the experiment definition, but users may need to manipulate them directly.

To read image information:

Images are created by operations on a container, but users can modify or delete their metadata:

As with other resources, these values overwrite the existing parameters (except for name which is a selector).

A user can delete an image:

Pubkey

Public/Private keypairs are used several places in the testbed for authentication and access. For example, access to containers that present a computer interface is done using the ssh protocol. These interfaces allow users to manipulate their keys.

Viewing keys:

Users can add and delete keys: