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.
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:
Only the following status codes are supported in response's HTTP Status-Lines:
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" )
rsl: "&( executable = \"bin/echo\" ) (arguments = \"hello\" )"
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.
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
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:
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:
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 <em>mask</em> <em>callback-contact</em>"
The values of the emphasized text items are as below:
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 <em>callback-contact</em>"
The values of the emphasized text items are as below:
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:
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
"<em>signal</em>"
The values of the emphasized text items are as below:
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:
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 procede 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.
The following security attributes are needed to communicate with the Gatekeeper:
2004-08-11 Added information about gridmap choosing
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