[[filebeat-modules-devguide]] == Creating a New Filebeat Module This guide will walk you through creating a new Filebeat module. All Filebeat modules currently live in the main https://github.com/elastic/beats[Beats] repository. To clone the repository and build Filebeat (which you will need for testing), please follow the general instructions in <>. [float] === Overview Each Filebeat module is composed of one or more "filesets". We usually create a module for each service that we support (`nginx` for Nginx, `mysql` for Mysql, and so on) and a fileset for each type of log that the service creates. For example, the Nginx module has `access` and `error` filesets. You can contribute a new module (with at least one fileset), or a new fileset for an existing module. [float] === Creating a new fileset Regardless of whether you are creating a fileset in a new or existing module, the procedure is similar. Run the following command in the `filebeat` folder: [source,bash] ---- make create-fileset ---- You'll be prompted to enter a module and fileset name. Only use characters `[a-z]` and, if required, underscores (`_`). No other characters are allowed. For the module name, you can us either a new module name or an existing module name. If the module doesn't exist, it will be created. NOTE: In this guide we use `{fileset}` and `{module}` as placeholders for the fileset and module names. You need to replace these with the actual names you entered when your created the module and fileset. After running the `make create-fileset` command, you'll find the fileset, along with its generated files, under `module/{module}/{fileset}`. This directory contains the following files: [source,bash] ---- module/{module}/{fileset} ├── manifest.yml ├── config │   └── {fileset}.yml ├── ingest │   └── pipeline.json ├── _meta │   └── fields.yml │   └── kibana │    └── default └── test ---- Let's look at these files one by one. [float] ==== manifest.yml The `manifest.yml` is the control file for the module, where variables are defined and the other files are referenced. It is a YAML file, but in many places in the file, you can use built-in or defined variables by using the `{{.variable}}` syntax. The `var` section of the file defines the fileset variables and their default values. The module variables can be referenced in other configuration files, and their value can be overridden at runtime by the Filebeat configuration. As the fileset creator, you can use any names for the variables you define. Each variable must have a default value. So in it's simplest form, this is how you can define a new variable: [source,yaml] ---- var: - name: pipeline default: with_plugins ---- Most fileset should have a `paths` variable defined, which sets the default paths where the log files are located: [source,yaml] ---- var: - name: paths default: - /example/test.log* os.darwin: - /usr/local/example/test.log* - /example/test.log* os.windows: - c:/programdata/example/logs/test.log* ---- There's quite a lot going on in this file, so let's break it down: * The name of the variable is `paths` and the default value is an array with one element: `"/example/test.log*"`. * Note that variable values don't have to be strings. They can be also numbers, objects, or as shown in this example, arrays. * We will use the `paths` variable to set the prospector {filebeat}/configuration-filebeat-options.html#prospector-paths[paths] setting, so "glob" values can be used here. * Besides the `default` value, the file defines values for particular operating systems: a default for darwin/OS X/macOS systems and a default for Windows systems. These are introduced via the `os.darwin` and `os.windows` keywords. The values under these keys become the default for the variable, if Filebeat is executed on the respective OS. Besides the variable definition, the `manifest.yml` file also contains references to the ingest pipeline and prospector configuration to use (see next sections): [source,yaml] ---- ingest_pipeline: ingest/pipeline.json prospector: config/testfileset.yml ---- These should point to the respective files from the fileset. Note that when evaluating the contents of these files, the variables are expanded, which enables you to select one file or the other depending on the value of a variable. For example: [source,yaml] ---- ingest_pipeline: ingest/{{.pipeline}}.json ---- This example selects the ingest pipeline file based on the value of the `pipeline` variable. For the `pipeline` variable shown earlier, the path would resolve to `ingest/with_plugins.json` (assuming the variable value isn't overridden at runtime.) [float] ==== config/*.yml The `config/` folder contains template files that generate Filebeat prospector configurations. The Filebeat prospectors are primarily responsible for tailing files, filtering, and multi-line stitching, so that's what you configure in the template files. A typical example looks like this: [source,yaml] ---- type: log paths: {{ range $i, $path := .paths }} - {{$path}} {{ end }} exclude_files: [".gz$"] ---- You'll find this example in the template file that gets generated automatically when you run `make create-fileset`. In this example, the `paths` variable is used to construct the `paths` list for the {filebeat}/configuration-filebeat-options.html#prospector-paths[paths] option. Any template files that you add to the `config/` folder need to generate a valid Filebeat prospector configuration in YAML format. The options accepted by the prospector configuration are documented in the {filebeat}/configuration-filebeat-options.html[Filebeat Prospectors] section of the Filebeat documentation. The template files use the templating language defined by the https://golang.org/pkg/text/template/[Golang standard library]. Here is another example that also configures multiline stitching: [source,yaml] ---- type: log paths: {{ range $i, $path := .paths }} - {{$path}} {{ end }} exclude_files: [".gz$"] multiline: pattern: "^# User@Host: " negate: true match: after ---- Although you can add multiple configuration files under the `config/` folder, only the file indicated by the `manifest.yml` file will be loaded. You can use variables to dynamically switch between configurations. [float] ==== ingest/*.json The `ingest/` folder contains Elasticsearch {elasticsearch}/ingest.html[Ingest Node] pipeline configurations. The Ingest Node pipelines are responsible for parsing the log lines and doing other manipulations on the data. The files in this folder are JSON documents representing {elasticsearch}/pipeline.html[pipeline definitions]. Just like with the `config/` folder, you can define multiple pipelines, but a single one is loaded at runtime based on the information from `manifest.yml`. The generator creates a JSON object similar to this one: [source,json] ---- { "description": "Pipeline for parsing {module} {fileset} logs", "processors": [ ], "on_failure" : [{ "set" : { "field" : "error.message", "value" : "{{ _ingest.on_failure_message }}" } }] } ---- From here, you would typically add processors to the `processors` array to do the actual parsing. For details on how to use ingest node processors, see the {elasticsearch}/ingest-processors.html[ingest node documentation]. In particular, you will likely find the {elasticsearch}/grok-processor.html[Grok processor] to be useful for parsing. Here is an example for parsing the Nginx access logs. [source,json] ---- { "grok": { "field": "message", "patterns":[ "%{IPORHOST:nginx.access.remote_ip} - %{DATA:nginx.access.user_name} \\[%{HTTPDATE:nginx.access.time}\\] \"%{WORD:nginx.access.method} %{DATA:nginx.access.url} HTTP/%{NUMBER:nginx.access.http_version}\" %{NUMBER:nginx.access.response_code} %{NUMBER:nginx.access.body_sent.bytes} \"%{DATA:nginx.access.referrer}\" \"%{DATA:nginx.access.agent}\"" ], "ignore_missing": true } } ---- Note that you should follow the convention of naming of fields prefixed with the module and fileset name: `{module}.{fileset}.field`, e.g. `nginx.access.remote_ip`. Also, please review our <>. While developing the pipeline definition, we recommend making use of the {elasticsearch}/simulate-pipeline-api.html[Simulate Pipeline API] for testing and quick iteration. [float] ==== _meta/fields.yml The `fields.yml` file contains the top-level structure for the fields in your fileset. It is used as the source of truth for: * the generated Elasticsearch mapping template * the generated Kibana index pattern * the generated documentation for the exported fields Besides the `fields.yml` file in the fileset, there is also a `fields.yml` file at the module level, placed under `module/{module}/_meta/fields.yml`, which should contain the fields defined at the module level, and the description of the module itself. In most cases, you should add the fields at the fileset level. [float] ==== test In the `test/` directory, you should place sample log files generated by the service. We have integration tests, automatically executed by CI, that will run Filebeat on each of the log files under the `test/` folder and check that there are no parsing errors and that all fields are documented. In addition, assuming you have a `test.log` file, you can add a `test.log-expected.json` file in the same directory that contains the expected documents as they are found via an Elasticsearch search. In this case, the integration tests will automatically check that the result is the same on each run. [float] === Module-level files Besides the files in the fileset folder, there is also data that needs to be filled at the module level. [float] ==== _meta/docs.asciidoc This file contains module-specific documentation. You should include information about which versions of the service were tested and the variables that are defined in each fileset. [float] ==== _meta/fields.yml The module level `fields.yml` contains descriptions for the module-level fields. Please review and update the title and the descriptions in this file. The title is used as a title in the docs, so it's best to capitalize it. [float] ==== _meta/kibana This folder contains the sample Kibana dashboards for this module. To create them, you can build them visually in Kibana and then run the following command: [source,shell] ---- $ cd dev-tools/cmd/dashboards $ make # if export_dashboard is not built $ ./export_dashboards -dashboard '{dashboard-id}' -output '../../../filebeat/module/{module}/_meta/kibana/default/dashboard' ---- New Filebeat modules might not be compatible with Kibana 5.x. To export dashboards that are compatible with 5.x, run the following command inside the developer virtualenv: [source,shell] ---- $ cd filebeat $ make python-env $ cd module/{module}/ $ python ../../../dev-tools/export_5x_dashboards.py --regex {module} --dir _meta/kibana/5.x ---- Where the `--regex` parameter should match the dashboard you want to export. Please note that dashboards exported from Kibana 5.x are not compatible with Kibana 6.x. You can find more details about the process of creating and exporting the Kibana dashboards by reading {beatsdevguide}/new-dashboards.html[this guide].