Ubuntu Manpage: globus_gram_protocol_definition

Provided by: libglobus-gram-protocol-doc_13.6-2_all

NAME

globus_gram_protocol_definition - GRAM Protocol Definition

The GRAM Protocol is used to handle communication between the Gatekeeper, Job Manager, and
GRAM Clients. The protocol is based on a subset of the HTTP/1.1 protocol, with a small set
of message types and responses sent as the body of the HTTP requests and responses. This
document describes GRAM Protocol version 2.

Framing
GRAM messages are framed in HTTP/1.1 messages. However, only a small subset of the HTTP
specification is used or understood by the GRAM system. All GRAM requests are HTTP POST
messages. Only the following HTTP headers are understood:

• Host

• Content-Type (set to 'application/x-globus-gram' in all cases)

• Content-Length

• Connection (set to 'close' in all HTTP responses)

Only the following status codes are supported in response's HTTP Status-Lines:

• 200 OK

• 403 Forbidden

• 404 Not Found

• 500 Internal Server Error

• 400 Bad Request

Message Format
All messages use the carriage return (ASCII value 13) followed by line feed (ASCII value
10) sequence to delimit lines. In all cases, a blank line separates the HTTP header from
the message body. All application/x-globus-gram message bodies consist of attribute names
followed by a colon, a space, and then the value of the attribute. When the value may
contain a newline or double-quote character, a special escaping rule is used to
encapsulate the complete string. This encapsulation consists of surrounding the string
with double-quotes, and escaping all double-quote and backslash characters within the
string with a backslash. All other characters are sent without modification. For example,
the string

rsl: &( executable = "/bin/echo" )
( arguments = "hello" )

becomes

rsl: "&( executable =
(arguments =

This is the only form of quoting which application/x-globus-gram messages support. Use of
% HEX HEX escapes (such as seen in URL encodings) is not meaningful for this protocol.

Message Types
Ping Request
A ping request is used to verify that the gatekeeper is configured properly to handle a
named service. The ping request consists of the following:

POST ping/job-manager-name HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version

The values of the message-specific strings are

job-manager-name
The name of the service to have the gatekeeper check. The service name corresponds to
one of the gatekeeper's configured grid-services, and is usually of the form
'jobmanager-scheduler-type'.

host-name
The name of the host on which the gatekeeper is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

Job Request
A job request is used to scheduler a job remotely using GRAM. The ping request consists of
the HTTP framing described above with the request-URI consisting of job-manager-name,
where job-manager name is the name of the service to use to schedule the job. The format
of a job request message consists of the following:

POST job-manager-name[@user-name] HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
job-state-mask: mask
callback-url: callback-contact
rsl: rsl-description

The values of the emphasized text items are as below:

job-manager-name
The name of the service to submit the job request to. The service name corresponds to
one of the gatekeeper's configured grid-services, and is usually of the form
'jobmanager-scheduler-type'.

user-name
Starting with GT4.0, a client may request that a certain account by used by the
gatekeeper to start the job manager. This is done optionally by appending the @ symbol
and the local user name that the job should be run as to the job-manager-name. If the
@ and username are not present, then the first grid map entry will be used. If the
client credential is not authorized in the grid map to use the specified account, an
authorization error will occur in the gatekeeper.

host-name
The name of the host on which the gatekeeper is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

mask
An integer representation of the job state mask. This value is obtained from a
bitwise-OR of the job state values which the client wishes to receive job status
callbacks about. These meanings of the various job state values are defined in the
GRAM Protocol API documentation.

callback-contact
A https URL which defines a GRAM protocol listener which will receive job state
updates. The from a bitwise-OR of the job state values which the client wishes to
receive job status callbacks about. The job status update messages are defined below.

rsl-description
A quoted string containing the RSL description of the job request.

Status Request
A status request is used by a GRAM client to get the current job state of a running job.
This type of message can only be sent to a job manager's job-contact (as returned in the
reply to a job request message). The format of a job request message consists of the
following:

POST job-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'status'

The values of the emphasized text items are as below:

job-contact
The job contact string returned in a response to a job request message, or determined
by querying the MDS system.

host-name
The name of the host on which the job manager is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

Callback Register Request
A callback register request is used by a GRAM client to register a new callback contact to
receive GRAM job state updates. This type of message can only be sent to a job manager's
job-contact (as returned in the reply to a job request message). The format of a job
request message consists of the following:

POST job-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'register mask callback-contact'

The values of the emphasized text items are as below:

job-contact
The job contact string returned in a response to a job request message, or determined
by querying the MDS system.

host-name
The name of the host on which the job manager is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

Callback Unregister Request
A callback unregister request is used by a GRAM client to request that the job manager no
longer send job state updates to the specified callback contact. This type of message can
only be sent to a job manager's job-contact (as returned in the reply to a job request
message). The format of a job request message consists of the following:

POST job-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'unregister callback-contact'

The values of the emphasized text items are as below:

job-contact
The job contact string returned in a response to a job request message, or determined
by querying the MDS system.

host-name
The name of the host on which the job manager is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

callback-contact
A https URL which defines a GRAM protocol listener which should no longer receive job
state updates. The from a bitwise-OR of the job state values which the client wishes
to receive job status callbacks about. The job status update messages are defined
below.

Job Cancel Request
A job cancel request is used by a GRAM client to request that the job manager terminate a
job. This type of message can only be sent to a job manager's job-contact (as returned in
the reply to a job request message). The format of a job request message consists of the
following:

POST job-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'cancel'

The values of the emphasized text items are as below:

job-contact
The job contact string returned in a response to a job request message, or determined
by querying the MDS system.

host-name
The name of the host on which the job manager is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

Job Signal Request
A job signal request is used by a GRAM client to request that the job manager process a
signal for a job. The arguments to the various signals are discussed in the
globus_gram_protocol_job_signal_t documentation.

POST job-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'signal'

The values of the emphasized text items are as below:

job-contact
The job contact string returned in a response to a job request message, or determined
by querying the MDS system.

host-name
The name of the host on which the job manager is running. This exists only for
compatibility with the HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

signal
A quoted string containing the signal number and it's parameters.

Job State Updates
A job status update message is sent by the job manager to all registered callback contacts
when the job's status changes. The format of the job status update messages is as follows:

POST callback-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
job-manager-url: job-contact
status: status-code
failure-code: failure-code

The values of the emphasized text items are as below:

callback-contact
The callback contact string registered with the job manager either by being passed as
the callback-contact in a job request message or in a callback register message.

host-name
The host part of the callback-contact URL. This exists only for compatibility with the
HTTP/1.1 protocol.

message-size
The length of the content of the message, not including the HTTP/1.1 header.

version
The version of the GRAM protocol which is being used. For the protocol defined in this
document, the value must be the string '2'.

job-contact
The job contact of the job which has changed states.

Proxy Delegation
A proxy delegation message is sent by the client to the job manager to initiate a
delegation handshake to generate a new proxy credential for the job manager. This
credential is used by the job manager or the job when making further secured connections.
The format of the delegation message is as follows:

POST callback-contact HTTP/1.1
Host: host-name
Content-Type: application/x-globus-gram
Content-Length: message-size

protocol-version: version
'renew'

If a successful (200) reply is sent in response to this message, then the client will
proceed with a GSI delegation handshake. The tokens in this handshake will be framed with
a 4 byte big-endian token length header. The framed tokens will then be wrapped using the
GLOBUS_IO_SECURE_CHANNEL_MODE_SSL_WRAP wrapping mode. The job manager will frame response
tokens in the same manner. After the job manager receives its final delegation token, it
will respond with another response message that indicates whether the delegation was
processed or not. This response message is a standard GRAM response message.

Note on Security Attributes
The following security attributes are needed to communicate with the Gatekeeper:

• Authentication must be done using GSSAPI mutual authentication

• Messages must be wrapped with support for the delegation message. When using Globus I/O,
this is accomplished by using the the GLOBUS_IO_SECURE_CHANNEL_MODE_GSI_WRAP wrapping
mode.

Changes
2004-08-11 Added information about gridmap choosing