--- title: "Java OutputStream Output" description: "write TenXObject and template values to a Java OutputStream/Writer instance" source: "https://github.com/log-10x/modules/tree/main/pipelines/run/modules/output/event/outputStream/module.yaml" icon: "material/language-java" --- Defines a Java [OutputStream](https://www.baeldung.com/java-outputstream){target="\_blank"} to write [TenXObject](https://doc.log10x.com/api/js/#TenXObject "Provide structured, reflective access to log/trace events read from input(s).") instance and template field values. OutputStreams provide a simple mechanism for adding custom output destinations to write TenXObject/Summary/Template values. For an example of a custom OutputStream implementation see [UnixSocketOutputStream](https://github.com/log-10x/pipeline-extensions/blob/main/edge-extensions/src/main/java/com/log10x/ext/edge/output/unix/UnixSocketOutputStream.java#L19){target="\_blank"} ## :material-wrench-outline: Config Files To configure the Java OutputStream output module, [:material-cog: Edit](https://doc.log10x.com/config/app/#module-config "Learn how to edit app and module configurations") these files. Below is the default configuration from: [outputStream/config.yaml](https://github.dev/log-10x/config/blob/main/pipelines/run/output/event/outputStream/config.yaml "outputStream/config.yaml"){target="\_blank"} (** Required Fields*).
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```yaml # 🔟❎ 'run' output stream configuration # Configure a Java OutputStream to write TenXObject field and templates values. # To learn more see https://doc.log10x.com/run/output/event/outputStream/ # Set the 10x pipeline to 'run' tenx: run # =============================== Dependencies ================================ include: run/modules/output/event/outputStream # ============================ OutputStream Options =========================== # Multiple OutputStream file outputs can be defined below outputStream: # ----------------------------- Object Output ------------------------------ # 'writeObjects' controls whether to write TenXObject field values to output. - writeObjects: true # (❗ REQUIRED) # ------------------------- OutputStream Options ------------------------- # 'class' specifies the class derived from java.io.OutputStream # that is instantiated, written to and closed by the 10x host JVM # In this example, values are written to a Unix domain socket class: com.log10x.ext.edge.output.unix.UnixSocketOutputStream # 'args' provides an optional mechanism to pass an Object[] value # to the constructor of 'class' that contains implementation-specific # configuration values. In this example, we calculate and set the # file name used by the Unix domain socket to write which TenXObject instance/template values. args: - address - '$=path("/tenx.socket")' # 'groupKeys' provides an optional mechanism for grouping instances of # 'class' according to a unique set of values. Grouping allows multiple # outputs such as this output and the template output below it to # share a single instance of 'class' which is effective when writing # to OutputStream, which holds a mutually exclusive resource. In this # example, outputs are grouped by the address of the client Unix domain socket. groupKeys: - '$=path("/tenx.socket")' # --------------------------- Encoding Options ---------------------------- # 'filter' sets a JavaScript expression that TenXObjects must evaluate as truthy to write to the output. # To learn more see https://doc.log10x.com/run/output/receive/#filter-expressions filter: isObject # 'fields' defines the fields to write for each TenXObject sent to this output. # To learn more see https://doc.log10x.com/run/output/stream/#outputfields fields: - encode() # 'encodeType' specifies how 'fields' are encoded to output. Possible values: [json,delimited]. # To learn more see https://doc.log10x.com/run/output/event/outputStream/#outputstreamencodetype encodeType: delimited # 'encodeDelimiter' sets the char delimiter used to separate TenXObject # field values when 'encodeType' is set to: 'delimited' encodeDelimiter: ',' # ---------------------------- Template Output ---------------------------- # 'writeTemplates' controls whether to write template values for TenXObjects passed to # to file. Only new templates are written. - writeTemplates: true # ------------------------- OutputStream Options ------------------------- # The file output below writes the template values of TenXObjects # passed to this file location. To learn more about TenXTemplates, see: # https://doc.log10x.com/run/template # For descriptions of 'class', 'args', and 'groupKeys', see the # object output stream above. class: com.log10x.ext.edge.output.unix.UnixSocketOutputStream args: - address - '$=path("/tenx.socket")' groupKeys: - '$=path("/tenx.socket")' ``` ## :material-menu: Options Specify the options below to [configure](/config "configure") multiple Java OutputStream output: |Name|Description|Category| |---|---|---| |[outputStreamClass](#outputstreamclass "fully2 qualified java.io.OutputStream/Writer sub-class name")|Fully2 qualified java.io.OutputStream/Writer sub-class name|General| |[outputStreamArgs](#outputstreamargs "arguments to pass to the constructor of 'outputStreamClass'")|Arguments to pass to the constructor of 'outputStreamClass'|General| |[outputStreamFilter](#outputstreamfilter "a JavaScript expression an TenXObject must evaluate as 'truthy' against to be written to this output")|A JavaScript expression an TenXObject must evaluate as 'truthy' against to be written to this output|General| |[outputStreamFields](#outputstreamfields "list of TenXObject field names to encode")|List of TenXObject field names to encode|Encode| |[outputStreamWriteObjects](#outputstreamwriteobjects "if true, TenXObject field values specified by [outputStreamFields](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields) are encoded to this output")|If true, TenXObject field values specified by \[outputStreamFields\](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields) are encoded to this output|Encode| |[outputStreamWriteTemplates](#outputstreamwritetemplates "if true, write new TenXTemplates to this output")|If true, write new TenXTemplates to this output|Encode| |[outputStreamEncodeType](#outputstreamencodetype "the output format in which to encode TenXObject values. Possible values:[json, delimited]")|The output format in which to encode TenXObject values. Possible values:\[json, delimited\]|Encode| |[outputStreamEncodedLinePrefix](#outputstreamencodedlineprefix "the line prefix prepended to the encoded event if 'outputStreamEncodeType' is 'delimited'")|The line prefix prepended to the encoded event if 'outputStreamEncodeType' is 'delimited'|Encode| |[outputStreamEncodeDelimiter](#outputstreamencodedelimiter "the delimiter placed between key and values pairs if 'outputStreamEncodeType' is 'delimited'")|The delimiter placed between key and values pairs if 'outputStreamEncodeType' is 'delimited'|Encode| |[outputStreamGroupKeys](#outputstreamgroupkeys "values to assign an 'outputStream' to a target output instance")|Values to assign an 'outputStream' to a target output instance|Advanced| ### General #### :material-menu-right-outline:**`outputStreamClass`** Fully2 qualified java.io.OutputStream/Writer sub-class name. |Type|Required|Category| |---|---|---| |String|✔|General| specifies a fully qualified [OutputStream](https://docs.oracle.com/javase/8/docs/api/java/io/OutputStream.html){target="\_blank"} or [Writer](https://docs.oracle.com/javase/8/docs/api/java/io/Writer.html){target="\_blank"} sub-class to instantiate. The specified [outputStreamFields](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields "list of TenXObject field names to encode") of each encoded TenXObjects will be written to the stream with a matching call to its [flush](https://docs.oracle.com/javase/8/docs/api/java/io/Flushable.html#flush--){target="\_blank"} method after each instance. The class must implement a parameterless constructor or one with the following signature: ```java /** * @param args * The values of the 'outputStream' option group specified * for this OutputStream/Writer instance provided as a map(=...). * This allows the stream to read configuration values provided via config files/command line arguments. * * @param evaluatorBean * An evaluator bean to enable this stream to interact with the 10x Engine */ public MyOutputStream(Map args, com.log10x.api.bean.EvaluatorBean evaluatorBean){...} ``` #### :material-menu-right-outline:**`outputStreamArgs`** Arguments to pass to the constructor of 'outputStreamClass'. |Type|Default|Category| |---|---|---| |List|\[\]|General| Value pairs to insert to the OutputStream/Writer constructor 'args' Map. This argument adds configuration values to the map passed to Stream/Writer ctor in addition to those specified by its matching 'outputStream' option group instance. This argument allows for providing stream-specific context and default values such as a host address, port, etc. #### :material-menu-right-outline:**`outputStreamFilter`** A JavaScript expression an TenXObject must evaluate as 'truthy' against to be written to this output. |Type|Default|Category| |---|---|---| |String|""|General| Specifies a JavaScript expression that an TenXObject must evaluate as truthy to write its instance/template field values to this output. For example, to only emit [timestamped](https://doc.log10x.com/api/js/#TenXBaseObject+timestamped "Return true if length of timestamp is greater than 0") TenXObjects, specify: ```yaml outputStreamFilter: this.timestamped ``` ### Encode #### :material-menu-right-outline:**`outputStreamFields`** List of TenXObject field names to encode. |Type|Default|Category| |---|---|---| |List|\[\]|Encode| Specifies a list of TenXObject intrinsic/calculated/extracted field names to extract and write to the output. #### :material-menu-right-outline:**`outputStreamWriteObjects`** If true, TenXObject field values specified by \[outputStreamFields\](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields) are encoded to this output. |Type|Default|Category| |---|---|---| |String|true|Encode| Determine whether to write [outputStreamFields](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields "list of TenXObject field names to encode") values of an TenXObject passed to this output. This configuration is typically defined using a JavaScript expression. To enable/disable the output depending on whether a launch argument, environment variable, or JVM -D option evaluates as truthy, use: ```yaml outputStreamWriteObjects: $=TenXEnv.get("myOutputStreamClass") ``` To learn more see [TenXEnv.get](https://doc.log10x.com/api/js/#TenXEnv.get). #### :material-menu-right-outline:**`outputStreamWriteTemplates`** If true, write new TenXTemplates to this output. |Type|Default|Category| |---|---|---| |String|false|Encode| Controls whether to write template values of TenXObjects passed to this output. The output will only emit TenXTemplates that the pipeline did not load at startup via the [templateFile](https://doc.log10x.com/run/template/#templatefiles "input files or glob patterns containing JSON-encoded TenXTemplates") argument, and will only emit an TenXTemplate once based on its [templateHash](https://doc.log10x.com/api/js/#TenXBaseObject+templateHash "An alphanumeric encoded value of a 64bit hash of the current object's template field.") value. #### :material-menu-right-outline:**`outputStreamEncodeType`** The output format in which to encode TenXObject values. Possible values:\[json, delimited\]. |Type|Default|Category| |---|---|---| |String|delimited|Encode| Specifies how to encode [outputStreamFields](https://doc.log10x.com/run/output/event/outputStream/#outputstreamfields "list of TenXObject field names to encode") values to this output. Possible values: - **json**: formats names and values for the current TenXObject as: {"field":"str","field2":1, "field3": true} - **delimited**: formats values for the current TenXObject as: "str",1,true The [outputStreamEncodeDelimiter](https://doc.log10x.com/run/output/event/outputStream/#outputstreamencodedelimiter "the delimiter placed between key and values pairs if 'outputStreamEncodeType' is 'delimited'") argument determines the separator to use. #### :material-menu-right-outline:**`outputStreamEncodedLinePrefix`** The line prefix prepended to the encoded event if 'outputStreamEncodeType' is 'delimited'. |Type|Default|Category| |---|---|---| |String||Encode| Sets the char which is prepended to the emitted TenXObject field values when [outputStreamEncodeType](https://doc.log10x.com/run/output/event/outputStream/#outputstreamencodetype "the output format in which to encode TenXObject values. Possible values:[json, delimited]") is `delimited`. #### :material-menu-right-outline:**`outputStreamEncodeDelimiter`** The delimiter placed between key and values pairs if 'outputStreamEncodeType' is 'delimited'. |Type|Default|Category| |---|---|---| |String|" "|Encode| Sets the char delimiter to separate TenXObject field values when [outputStreamEncodeType](https://doc.log10x.com/run/output/event/outputStream/#outputstreamencodetype "the output format in which to encode TenXObject values. Possible values:[json, delimited]") is `delimited`. ### Advanced #### :material-menu-right-outline:**`outputStreamGroupKeys`** Values to assign an 'outputStream' to a target output instance. |Type|Default|Category| |---|---|---| |List|\[\]|Advanced| Specifies a list of values by which instances of the 'outputStream' option group are assigned to specific instances of 'outputStreamClass' to enable multiple outputs to use a single synchronized OutputStream instance.
:material-github: This module is defined in [outputStream/module.yaml](https://github.com/log-10x/modules/tree/main/pipelines/run/modules/output/event/outputStream/module.yaml "outputStream/module.yaml"){target="\_blank"}.