= Exec Component
:doctitle: Exec
:shortname: exec
:artifactid: camel-exec
:description: Execute commands on the underlying operating system.
:since: 2.3
:supportlevel: Stable
:component-header: Only producer is supported
//Manually maintained attributes
:camel-spring-boot-name: exec

*Since Camel {since}*

*{component-header}*

The Exec component can be used to execute system commands.

== Dependencies

Maven users need to add the following dependency to their `pom.xml`

[source,xml]
-------------------------------------
<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-exec</artifactId>
  <version>${camel-version}</version>
</dependency>
-------------------------------------

where `${camel-version`} must be replaced by the actual version of Camel.

== URI format

---------------------------
exec://executable[?options]
---------------------------

where `executable` is the name, or file path, of the system command that
will be executed. If executable name is used (e.g. `exec:java`), the
executable must in the system path.

// component-configure options: START

// component-configure options: END

// component options: START
include::partial$component-configure-options.adoc[]
include::partial$component-endpoint-options.adoc[]
// component options: END

// endpoint options: START

// endpoint options: END


== Message headers

The supported headers are defined in
`org.apache.camel.component.exec.ExecBinding`.

[width="100%",cols="10%,10%,10%,70%",options="header",]
|=======================================================================
|Name |Type |Message |Description

|`ExecBinding.EXEC_COMMAND_EXECUTABLE` |`String` |`in` |The name of the system command that will be executed. Overrides
`executable` in the URI.

|`ExecBinding.EXEC_COMMAND_ARGS` |`java.util.List<String>` |`in` |Command-line arguments to pass to the executed process. The arguments
are used literally - no quoting is applied. Overrides any existing
`args` in the URI.

|`ExecBinding.EXEC_COMMAND_ARGS` |`String`| `in` |The arguments of the executable as a Single string where
each argument is whitespace separated (see `args` in URI option). The
arguments are used literally, no quoting is applied. Overrides any
existing `args` in the URI.

|`ExecBinding.EXEC_COMMAND_OUT_FILE` |`String` |`in` |The name of a file, created by the executable, that should be considered
as its output. Overrides any existing `outFile` in the URI.

|`ExecBinding.EXEC_COMMAND_TIMEOUT` |`long` |`in` |The timeout, in milliseconds, after which the executable should be
terminated. Overrides any existing `timeout` in the URI.

|`ExecBinding.EXEC_COMMAND_WORKING_DIR` |`String` |`in` |The directory in which the command should be executed. Overrides any
existing `workingDir` in the URI.

|`ExecBinding.EXEC_EXIT_VALUE` |`int` |`out` |The value of this header is the _exit value_ of the executable. Non-zero
exit values typically indicate abnormal termination. Note that the exit
value is OS-dependent.

|`ExecBinding.EXEC_STDERR` |`java.io.InputStream` |`out` |The value of this header points to the standard error stream (stderr) of
the executable. If no stderr is written, the value is `null`.

|`ExecBinding.EXEC_USE_STDERR_ON_EMPTY_STDOUT` |`boolean` |`in` |Indicates that when `stdout` is empty, this component will populate the
Camel Message Body with `stderr`. This behavior is disabled (`false`) by
default.

|`ExecBinding.EXEC_COMMANDS_LOG_LEVEL` |`String` |`in` |Logging level to be used for commands during execution. The default value is DEBUG.
Possible values are TRACE, DEBUG, INFO, WARN, ERROR or OFF (Values of LoggingLevel enum)
|=======================================================================

== Message body

If the `Exec` component receives an `in` message body that is
convertible to `java.io.InputStream`, it is used to feed input to the
executable via its stdin. After execution,
http://camel.apache.org/exchange.html[the message body] is the result of
the execution,- that is, an
`org.apache.camel.components.exec.ExecResult` instance containing the
stdout, stderr, exit value, and out file. This component supports the
following `ExecResult` http://camel.apache.org/type-converter.html[type
converters] for convenience:

[width="100%",cols="50%,50%",options="header",]
|=======================================================================
|From |To

|`ExecResult` |`java.io.InputStream`

|`ExecResult` |`String`

|`ExecResult` |`byte []`

|`ExecResult` |`org.w3c.dom.Document`
|=======================================================================

If an out file is specified (in the endpoint via `outFile` or the
message headers via `ExecBinding.EXEC_COMMAND_OUT_FILE`), converters
will return the content of the out file. If no out file is used, then
this component will convert the stdout of the process to the target
type. For more details, please refer to the xref:exec-component.adoc[usage examples] below.

== Usage examples

=== Executing word count (Linux)

The example below executes `wc` (word count, Linux) to count the words
in file `/usr/share/dict/words`. The word count (output) is written to
the standard output stream of `wc`.

[source,java]
--------------------------------------------------------------------------------------
from("direct:exec")
.to("exec:wc?args=--words /usr/share/dict/words")
.process(new Processor() {
     public void process(Exchange exchange) throws Exception {
       // By default, the body is ExecResult instance
       assertIsInstanceOf(ExecResult.class, exchange.getIn().getBody());
       // Use the Camel Exec String type converter to convert the ExecResult to String
       // In this case, the stdout is considered as output
       String wordCountOutput = exchange.getIn().getBody(String.class);
       // do something with the word count
     }
});
--------------------------------------------------------------------------------------

=== Executing `java`

The example below executes `java` with 2 arguments: `-server` and
`-version`, provided that `java` is in the system path.

[source,java]
--------------------------------------
from("direct:exec")
.to("exec:java?args=-server -version")
--------------------------------------

The example below executes `java` in `c:\temp` with 3 arguments:
`-server`, `-version` and the sytem property `user.name`.

[source,java]
----------------------------------------------------------------------------------------------------
from("direct:exec")
.to("exec:c:/program files/jdk/bin/java?args=-server -version -Duser.name=Camel&workingDir=c:/temp")
----------------------------------------------------------------------------------------------------

=== Executing Ant scripts

The following example executes http://ant.apache.org/[Apache Ant]
(Windows only) with the build file `CamelExecBuildFile.xml`, provided
that `ant.bat` is in the system path, and that `CamelExecBuildFile.xml`
is in the current directory.

[source,java]
--------------------------------------------------
from("direct:exec")
.to("exec:ant.bat?args=-f CamelExecBuildFile.xml")
--------------------------------------------------

In the next example, the `ant.bat` command redirects its output to
`CamelExecOutFile.txt` with `-l`. The file `CamelExecOutFile.txt` is
used as the out file with `outFile=CamelExecOutFile.txt`. The example
assumes that `ant.bat` is in the system path, and that
`CamelExecBuildFile.xml` is in the current directory.

[source,java]
-------------------------------------------------------------------------------------------------------
from("direct:exec")
.to("exec:ant.bat?args=-f CamelExecBuildFile.xml -l CamelExecOutFile.txt&outFile=CamelExecOutFile.txt")
.process(new Processor() {
     public void process(Exchange exchange) throws Exception {
        InputStream outFile = exchange.getIn().getBody(InputStream.class);
        assertIsInstanceOf(InputStream.class, outFile);
        // do something with the out file here
     }
  });
-------------------------------------------------------------------------------------------------------

=== Executing `echo` (Windows)

Commands such as `echo` and `dir` can be executed only with the command
interpreter of the operating system. This example shows how to execute
such a command - `echo` - in Windows.

[source,java]
----------------------------------------------------------
from("direct:exec").to("exec:cmd?args=/C echo echoString")
----------------------------------------------------------



include::spring-boot:partial$starter.adoc[]
