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This document is part of the BioCompute Object User Guide

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2.5 Execution Domain “execution_domain”

This section defines the execution_domain part of the BCO.

The fields required for execution of the BCO have been encapsulated together in order to clearly separate information needed for deployment, software configuration and running applications in a dependent environment. One byproduct of an accurate BCO definition is facilitation of reproducibility as defined by the Oxford English Dictionary as “the extent to which consistent results are obtained when produced repeatedly.”

Condensed example:

"execution_domain": {
        "script_access_type": "text",
        "script": [
        ],
        "script_driver": "manual",
        "software_prerequisites": [
        ],
        "external_data_endpoints": [
        ], 
        "environment_variables": {
        }
}

2.5.1 Script “script”

The Script field points to internal or external references to a script object that was used to perform computations for this BCO instance. This may be a reference to an object in GitHub, a computational service or any other type of script.

 "script": ["https://example.com/workflows/antiviral_resistance_detection_hive.py"]

2.5.2 Script driver “script_driver”

This field provides a space to indicate what kind of executable can be launched in order to perform a sequence of commands described in the script (see above) in order to run the pipeline.

"script_driver": "shell"

2.5.3 Algorithmic tools and Software Prerequisites “software_prerequisites”

An optional multi-value field listing the minimal necessary prerequisites, library, tool versions needed to successfully run the script to produce BCO. The keys are name, version, and uri.

        "software_prerequisites": [
            {
                "name": "HIVE-hexagon", 
                "version": "babajanian.1",
                "uri": {
                    "uri": "http://example.com/dna.cgi?cmd=dna-hexagon&cmdMode=-",
                    "access_time": "2017-01-24T09:40:17-0500",
                    "sha1_chksum": "d60f506cddac09e9e816531e7905ca1ca6641e3c"
                }
            }, 
            {
                "name": "HIVE-heptagon", 
                "version": "albinoni.2",
                "uri": {
                    "uri": "http://example.com/dna.cgi?cmd=dna-heptagon&cmdMode=-",
                    "access_time": "2017-01-24T09:40:17-0500"
                }
            }
        ]

2.5.4 External Data Endpoints “external_data_endpoints”

An optional multi-value field listing the minimal necessary domain specific external data source access in order to successfully run the script to produce BCO. The values under this field present the requirements for network protocol endpoints used by a pipeline’s scripts, or other software.

The key url defines an endpoint to be accessed. If the path of the URL is / then any resource at the given domain may be accessed, while if the path is more specific than only resources which path prefix matches may be accessed.

The key name should describe the service that is accessed.

"external_data_endpoints": [

    {"url": "protocol://domain:port/application/path","name": "generic name"},

    {"url": "ftp://data.example.com:21/",
    "name": "access to ftp server"},

    {"url": "http://eutils.ncbi.nlm.nih.gov/entrez/eutils",
    "name": "access to e-utils web service"}
]

2.5.5 Environment Variables “environment_variables”

This is an array of key-value pairs useful to configure the execution environment on the target platform. For example, one might specify the number of compute cores, or available memory use of the script. The possible keys are specific to each platform. The “value” should be a JSON string. The regex is based on the following:

http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html Environment variable names used by the utilities in the Shell and Utilities volume of IEEE Std 1003.1-2001 consist solely of uppercase letters, digits, and the ‘_’ (underscore) from the characters defined in Portable Character Set and do not begin with a digit. Other characters may be permitted by an implementation; applications shall tolerate the presence of such names. Uppercase and lowercase letters shall retain their unique identities and shall not be folded together. The name space of environment variable names containing lowercase letters is reserved for applications. Applications can define any environment variables with names from this name space without modifying the behavior of the standard utilities. Note: Other applications may have difficulty dealing with environment variable names that start with a digit. For this reason, use of such names is not recommended anywhere.

        "environment_variables": {
            "HOSTTYPE": "x86_64-linux",
            "EDITOR": "vim"
        }
    }