Version

    SystemExecute

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

    Short Description

    SystemExecute executes system commands.

    ComponentSame input metadataSorted inputsInputsOutputsEach to all outputs[1]JavaCTLAuto-propagated metadata
    SystemExecute-⨯0-10-1-⨯⨯⨯

    [1]  Component sends each data record to all connected output ports.

    Ports

    Port typeNumberRequiredDescriptionMetadata
    Input0⨯For standard input of the specified system command (input of the process)Any1
    Output0[1]For a standard output of the specified system command (output of the process)Any2

    [1]  A standard output must be written to an output port or output file. If both an output port is connected and output file is specified, an output is sent to output port only.

    Metadata

    SystemExecute does not propagate metadata.

    SystemExecute has no metadata template.

    SystemExecute Attributes

    AttributeReqDescriptionPossible values
    Basic
    System commandyes

    A command to be executed by the system. The command is always saved to a tmp file as a script. In case an interpreter is specified, it executes that script. If the command requires an input, it has to be sent to the command through the optional input port. For details, see How it works.

    		 
    Process input/output charset 

    Encoding used for formatting/parsing data for input/from output of system process.

    The default encoding depends on DEFAULT_CHARSET_DECODER in defaultProperties.

    		UTF-8 | <any other>
    Output file URL[1]

    Name of a file, including the path, to which output of the process (together with errors) should be written if the output edge is not connected and if System command creates the standard output. For more information, see URL File Dialog.

    		 
    Append 

    By default, the contents of an output file is always deleted and overwritten by new data. If set to true, new output data is appended to the output file without deleting the file contents.

    		false (default) | true
    Command interpreter 

    An interpreter that should execute the command. If specified, System command is saved as a script to a temporary file and executed by this interpreter. Its form must be the following: <interpreter name> [parameters] ${} [parameters]. If an interpreter is defined, System command is saved to a temporary file and executed as a script. In such a case, the component replaces this ${} expression by the name of this temporary script file.

    See the list of well known interprets.

    		 
    Working directory A working directory of the component. current directory[2] (default) | other directory
    Advanced
    Number of error lines The number of lines that are printed if a command finishes with errors.2 (default) | 1-N
    Environment 

    System-dependent mapping from variables to values. Mappings are separated by a colon, semicolon or pipe. By default, the new value is appended to the environment of the current process. Both PATH=/home/user/mydir and PATH=/home/user/mydir!true means that /home/user/mydir will be appended to the existing PATH. Whereas PATH=/home/user/mydir!false replaces the old PATH value by the new one (/home/user/mydir).

    For example: PATH=/home/user/mydir[!true] (default) | PATH=/home/user/mydir!false

    Timeout for producer/consumer workers (ms) 

    Timeout; by default in milliseconds, but other time units may be used. For details, see Timeout.

    		0 (without limitation) | 1-n
    Ignore exit value 

    In case the executed system command returns non-zero value, the component fails. This option can change this behavior, the exit value can be ignored.

    		true | false (default)

    [1]  If the output port is not connected, a standard output can only be written to a specified output file. If the output port is connected, an output file will not be created and a standard output will be sent to the output port.

    [2]  A working directory defaults to current process working directory only if the graph runs on a local CloverDX engine. If it runs on the CloverDX Server, then the default working directory is the sandbox root. In the case of a Clustered Server environment, the default working directory is the sandbox root only if the sandbox is of a "shared" type, or it is of a "local" type and is located on the node running the SystemExecute component. Otherwise the Server node cannot access the sandbox locally, i.e. the sandbox is of type "local" but is located on a remote node, in which case the working directory defaults to some arbitrary temporary directory supplied by the Temp Space Management subsystem of the Server node. The component prints a message about which working directory was actually used into a graph run log at INFO log level.

    Details

    SystemExecute executes commands and arguments specified in the component itself as a separate process. The commands receive a standard input through the input port and send a standard output to the output port (if the command creates any output).

    How it works

    SystemExecute runs the command specified in the System command and creates two threads.

    • The first thread (producer) reads records from the input edge, serializes them and sends them to stdin of the command.

    • The second thread (consumer) reads stdout of the command, parses it and sends it to the output edge.

    Timeout

    • When the command ends, the component still waits until both the producer and the consumer also finish their work. The time is defined in the Timeout attribute.

    • By default, timeout is unlimited. In the case of an unexpected deadlock, you can set the timeout to any number of milliseconds.

    Well known command interprets

    The following list contains possible interprets that can be used in SystemExecute component. You are not limited to the items from this list.

    Windows

    • cmd /c ${}

    • powershell ${}

    Linux

    • /bin/sh ${}

    • /bin/bash ${}

    • /bin/tcsh ${}

    • /usr/bin/perl ${}

    • /usr/bin/python ${}

    Difference between SystemExecute and ExecuteScript

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

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

    Examples

    Run command on Linux
    Run command on Windows
    Run command that saves its output to file
    Calling external filter

    Run command on Linux

    This example shows execution of command on Linux using SystemExecute.

    Run the uptime command using the SystemExecute component. Send the results through an edge to the next component.

    Solution

    Connect the output port of SystemExecute with the next component. Metadata of the edge should contain just one string field.

    Configure SystemExecute.

    AttributeValue
    System commanduptime
    Command interpreter/bin/bash ${}

    Run command on Windows

    This example shows execution of command on MS Windows using SystemExecute

    Run tasklist using SystemExecute component. Send the results trough an edge to the next component.

    Solution

    Connect the output port of SystemExecute with the next component. Metadata of the edge should contain just one string field.

    Configure SystemExecute.

    AttributeValue
    System commandtasklist
    Process input/output charsetwindows-1252
    Command interpretercmd /c ${}
    [Note]Note

    If process input/output charset is not set or it is set incorrectly, you can encounter the following error message in the graph log: Character decoding error occurred. Set correct charset. Current charset is UTF-8.

    Run command that saves its output to file

    This example shows the way to run a command with SystemExecute and save the output from the command to a file.

    Run command who and save its output to the file logged_users.txt for further processing.

    Solution
    AttributeValue
    System commandwho
    Output file URL${DATAOUT_DIR}/logged_users.txt
    Command interpreter/bin/bash ${}

    Calling external filter

    This example shows the way to use an external shell filter from SystemExecute: the data from a graph is sent to input stream of the filter and the output of the script is sent back to the graph.

    Call sed to replace A with B.

    Solution

    Connect the input port of SystemExecute with the component producing the data and the output port of SystemExecute with the component consuming the data. Assign metadata to the edges. The metadata on both edges should be the same, unless the script changes the number of columns or delimiters.

    AttributeValue
    System commandsed 's_A_B_g'
    Command interpreter/bin/bash ${}

    Best Practices

    We recommend users to explicitly specify Process input/output charset.