Version

    ExecuteScript

    Short Description
    Ports
    Metadata
    ExecuteScript Attributes
    Details
    Examples
    Best Practices
    See also

    Short Description

    ExecuteScript is a component that runs either shell scripts or scripts interpreted by a selected interpreter. It either runs a script only once or repeatedly for each incoming record. Each incoming record can redefine almost all parameters of a run including the script itself.

    Ports

    Port typeNumberRequiredDescriptionMetadata
    Input0
    no
    		Parameters of a script run (including a script itself if needed).Any
    Output0
    no
    		A component input and results of a script run.Any
    Error1
    no
    		A component input and results of a script run. Records for scripts that cannot run or return 1.Any

    Metadata

    ExecuteScript does not propagate metadata from left to right or from right to left.

    This component has metadata templates available. See general details on metadata templates.

    The metadata template ExecuteScript_RunConfig available on the first input port is described in Input Mapping Fields Description.

    The metadata template ExecuteScript_RunResult available on output ports is described in Output Mapping Fields Description.

    ExecuteScript Attributes

    AttributeReqDescriptionPossible values
    Basic
    Scriptno

    Code of a script to be executed. If the interpreter attribute value is kept default, the script must be code of a shell script. Thus, it can easily be used for running one or more system commands. Otherwise, the code format depends on a chosen interpreter.

    		 
    Script URLno

    A URL of a script to be executed. If the interpreter attribute value is kept default, the script must be code of a shell script. Thus, it can easily be used for running one or more system commands. Otherwise, the code format depends on the chosen interpreter. If both the Script and Script URL attributes are specified, only Script URL is used.

    		 
    Script charsetno

    This character encoding is used for an executed script file. A script file reference is specified either in the Script URL attribute or a temporary batch file is created automatically from the Script attribute.

    The default encoding depends on DEFAULT_CHARSET_DECODER in defaultProperties.

    		UTF-8 (default) | <other encodings>
    Working directoryno

    A working directory of the executed script. All relative paths used inside the script will be interpreted with respect to this directory. By default, it is set to the root of the CloverDX project containing the graph.

    		 
    Timeoutno

    A limit for script execution (in milliseconds). The limit can be set in other units than milliseconds. See Time Intervals.

    When a script runs longer than the limit, the components terminates it. In this case in the output, record fields are set as follows: exitValue is set to 1, reachedTimeout to true and duration is greater or equal to timeout.

    		0 (unlimited) | positive number
    Input Mappingno

    Input mapping defines how data from an incoming token overrides default component settings. See input mapping fields description

    		CTL transformation
    Output Mappingno

    Output mapping maps results of successful script executions to the first output port. See output mapping fields description

    		CTL transformation
    Error Mappingno

    Error mapping maps results of unsuccessful scripts to the second output port. See output mapping fields description

    		CTL transformation
    Redirect Error Outputno

    By default, results of failed scripts are sent to the second output port (error port). If this switch is set to true, results of unsuccessful scripts are sent to the first output port in the same way as successful scripts.

    		false (default) | true
    Advanced
    Interpreterno

    Set an interpreter to be used for running a script. When an interpreter is executed, ${} is substituted with a name of a temporary batch file that contains a copy of the script. If an interpreter is sensitive to an extension of a script file, it is necessary to set Script file extension property so that a temporary file will have the right extension.

    A path to an interpreter followed by ${}. By default a script is interpreted by a system shell (e.g. cmdin Windows and sh in Linux).

    Environment variablesno

    Sets environment variables values in the script. It allows either setting them or appending to them. Appending to a non-existing variable leads to defining it and setting its value. Note that variable values are only visible inside of the script, i.e. setting PATH cannot be used for setting a path to an interpreter. Variable values set in this property can be overridden by mapping of input to EnvironmentVariables metadata in an input mapping dialog.

    If you are appending a value to the system variable (e.g. $PATH), the correct system-dependent path delimiter should be used at the beginning of the appended value (colon on Linux, semicolon on Windows).

    		 
    Standard inputno

    Contents of a standard input that will be sent to the script. Be aware that if the script expects more input lines than available, it may hang.

    		string
    Standard input file URLno

    A file URL to contents of a standard input that will be sent to the script. Be aware that if the script expects more input lines than available, it may hang.

    		 
    Standard output file URLno

    A file URL of a file to store a standard output of the script. The file content is either rewritten or appended depending on the append flag.

    		 
    Error output file URLno

    A file URL of a file to store an error output of the script. The file content is either rewritten or appended depending on the append flag.

    		 
    Appendno

    Sets whether a standard output and error output written into files (Standard output file URL and Error output file URL attributes) should rewrite existing content or it should be appended.

    		false (default) | true
    Data charsetno

    Character encoding used to encode a standard input passed from an input port and to decode a standard and error output to be passed to output ports.

    		UTF-8 (default) | <other encodings>
    Script file extensionno

    Sets an extension of a batch file that is given to the interpreter (its name is substituted for ${} in the interpreter setting).

    		bat (default) | string
    Stop processing on failno

    By default, any failed script causes the component to stop executing other scripts and information about skipped tokens is sent to the error output port. This behavior can be disabled by this attribute. Note: this function works only if an edge is connected to the component's error port.

    		true (default) | false
    [Note]Note

    The contents of the Script attribute are copied to a temporary batch file. On Microsoft Windows, it is often useful to start the script with @echo off to disable echoing the executed commands.

    Details

    Input Mapping Fields Description
    Output Mapping Fields Description

    ExecuteScript runs a script with a given interpreter (default system shell by default).

    When there is no edge connected to an input port, the component runs the script only once. One output record is produced in this case.

    When there are records coming to an input port, one script execution per record is performed and one output record per script execution is produced.

    If the script is successful, the component continues with processing of the next input tokens. Otherwise, component stops executing other scripts and from now on, all incoming tokens are ignored and information about ignored tokens is sent to the error output port. This behavior can be changed in the Stop processing on fail parameter.

    The output record contains all important information about a script run (times, exit value, error reports and standard output). Mapping of these values to user-defined output metadata can be defined in Output Mapping and Error Mapping attributes. If the Output mapping is empty, fields of the RunStatus record are mapped to the output by name.

    All script execution parameters can be set via input records using the Input Mapping attribute. The mapping sets which values for the input are used as script execution parameters. Input and output mapping are common to job control components.

    A single run of a script is performed as follows:

    • The script code is copied to a temporary batch file.

    • An interpreter is run with a ${} string substituted with the name of the temporary file.

    • When the script is over, the output record is produced and sent to the first output port for successful runs and to the second output port for unsuccessful runs.

    For more detailed information see attribute description.

    Input Mapping Fields Description

    Input records can be mapped to two different metadata: RunConfig and EnvironmentVariables.

    Fields of RunConfig have the following functionality:

    FieldDescription
    scriptOverrides the attribute Script.
    scriptURLOverrides the attribute Script URL.
    scriptCharsetOverrides the attribute Script charset.
    interpreterOverrides the attribute Interpreter.
    workingDirectoryOverrides the attribute Working Directory.
    timeoutOverrides the attribute Timeout.
    environmentVariables

    Overrides the attribute Environment Variables. It is expected that the value contains a list of variable assignments delimited with ";". An assignment with a simple "=" symbol assigns a value to an assigned environment variable. An assignment with a "+=" symbol appends a value to an assigned environment variable.

    stdInOverrides the attribute Standard Input.
    stdInFileURLOverrides the attribute Standard Input File URL.
    stdOutFileURLOverrides the attribute Standard Output File URL.
    errOutFileURLOverrides the attribute Error Output File URL.
    appendOverrides the attribute Append.
    dataCharsetOverrides the attribute Data charset.
    scriptFileExtensionOverrides the attribute Script File Extension.
    [Note]Note

    In Input mapping, you can use the $out.0.script field to create a dynamic command line. Just map a script and its parameters onto the field. Example:

    $out.0.script = "md5.exe " + $in.0.filePath;

    [Note]Note

    Environment variables provided to the executed script can be defined in three different ways:

    1. Use the component's Environmental variables attribute for static definition of environment variables. Variable names and values are defined once for all script executions.

    2. The output record EnvironmentVariables populated in Input mapping is the second way how environment variables can be defined. Set of variable names is still statically defined by the record structure, but values of variables can be derived from input tokens.

    3. The most complex way how environment variables can be defined is to populate the environmentVariables field in the output record RunConfig in Input mapping. Value of this field has the same syntax and meaning as the Environment variables attribute. Set of variables as well as their values can be defined fully dynamically in this case.

    [Note]Note

    If you want to append a string to an environment variable in Input mapping, use the getEnvironmentVariables() CTL function. Example:

    $out.1.PATH = getEnvironmentVariables()["PATH"] + ":" + $in.0.additionalPath;

    Output Mapping Fields Description

    If output mapping is empty, fields of the input record and result record are mapped to the output by name.

    FieldDescription
    stdOutStandard output of a script.
    errOutError output of a script.
    startTimeStart time of a script.
    stopTimeStop time of a script.
    durationDuration of a script. (duration = stopTime - startTime)
    exitValueValue returned by the script. Typically, 0 means no error, non-zero values stand for errors.
    reachedTimeoutBoolean determining whether the script reached timeout.
    errException

    If the script call finishes with an error, it may contain an exception that caused the error. This happens only in a situation when the script has not started (e.g. the path to the script is not valid) or its run has been interrupted (e.g. when a timeout has been reached).

    errMessageMessage reported by the exception in errException.

    Difference between SystemExecute and ExecuteScript

    SystemExecute uses a data-oriented approach. It allows you to stream data from and to the script.

    ExecuteScript executes scripts in steps. It allows you to receive scripts from an input edge and execute them one by one.

    Examples

    Run shell script
    Using timeout
    Running scripts one by one

    Run shell script

    This example shows way to run a simple script. The script is specified in the component.

    Use ExecuteScript to run last command.

    Solution

    Attach an edge to the first output port of ExecuteScript component.

    Configure the ExecuteScript component in the following way.

    AttributeValue
    Scriptlast
    Interpreter/bin/bash ${}

    Using timeout

    Scripts may hang or run too long. This example shows how to set timeout in ExecuteScript.

    Use ExecuteScript to run my_calculation program, which is on the PATH. The program should not run longer than 5 seconds.

    Solution
    AttributeValue
    Scriptmy_calculation
    Timeout (ms)5s
    Interpreter/bin/bash ${}

    If the timeout is specified without units, it is in millisecond. It can be set in other units. See Time Intervals.

    If you need to terminate the script, but the graph should not fail, connect an edge to the second output port of ExecuteScript.

    Running scripts one by one

    ExecuteScript allows you to receive scripts from an input edge. This example shows a way to execute scripts one by one.

    Execute shell commands received from an input edge.

    Solution

    Connect edges to input and output ports. The commands to be executed are received in the script field.

    AttributeValue
    Input mapping 
    //#CTL2
function integer transform() {
    $out.0.script = $in.0.script;

    return ALL;
}
    Interpreter/bin/bash ${}

    Best Practices

    We recommend users to specify Data charset.

    If the script is in an external file (specified with Script URL), we recommend users to explicitly specify Script charset too.