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diff --git a/collectors/charts.d.plugin/README.md b/collectors/charts.d.plugin/README.md index 092a3f02..3e4edf56 100644 --- a/collectors/charts.d.plugin/README.md +++ b/collectors/charts.d.plugin/README.md @@ -1,20 +1,14 @@ -<!-- -title: "charts.d.plugin" -custom_edit_url: "https://github.com/netdata/netdata/edit/master/collectors/charts.d.plugin/README.md" -sidebar_label: "charts.d.plugin" -learn_status: "Published" -learn_topic_type: "Tasks" -learn_rel_path: "Developers/Collectors" ---> - # charts.d.plugin `charts.d.plugin` is a Netdata external plugin. It is an **orchestrator** for data collection modules written in `BASH` v4+. -1. It runs as an independent process `ps fax` shows it -2. It is started and stopped automatically by Netdata -3. It communicates with Netdata via a unidirectional pipe (sending data to the `netdata` daemon) -4. Supports any number of data collection **modules** +1. It runs as an independent process `ps fax` shows it +2. It is started and stopped automatically by Netdata +3. It communicates with Netdata via a unidirectional pipe (sending data to the `netdata` daemon) +4. Supports any number of data collection **modules** + +To better understand the guidelines and the API behind our External plugins, please have a look at the [Introduction to External plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md) prior to reading this page. + `charts.d.plugin` has been designed so that the actual script that will do data collection will be permanently in memory, collecting data with as little overheads as possible @@ -25,12 +19,11 @@ The scripts should have the filename suffix: `.chart.sh`. ## Configuration -`charts.d.plugin` itself can be configured using the configuration file `/etc/netdata/charts.d.conf` -(to edit it on your system run `/etc/netdata/edit-config charts.d.conf`). This file is also a BASH script. +`charts.d.plugin` itself can be [configured](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#use-edit-config-to-edit-configuration-files) using the configuration file `/etc/netdata/charts.d.conf`. This file is also a BASH script. In this file, you can place statements like this: -``` +```conf enable_all_charts="yes" X="yes" Y="no" @@ -48,36 +41,31 @@ A `charts.d.plugin` module is a BASH script defining a few functions. For a module called `X`, the following criteria must be met: -1. The module script must be called `X.chart.sh` and placed in `/usr/libexec/netdata/charts.d`. +1. The module script must be called `X.chart.sh` and placed in `/usr/libexec/netdata/charts.d`. -2. If the module needs a configuration, it should be called `X.conf` and placed in `/etc/netdata/charts.d`. - The configuration file `X.conf` is also a BASH script itself. - To edit the default files supplied by Netdata, run `/etc/netdata/edit-config charts.d/X.conf`, - where `X` is the name of the module. +2. If the module needs a configuration, it should be called `X.conf` and placed in `/etc/netdata/charts.d`. + The configuration file `X.conf` is also a BASH script itself. + You can edit the default files supplied by Netdata, by editing `/etc/netdata/edit-config charts.d/X.conf`, where `X` is the name of the module. -3. All functions and global variables defined in the script and its configuration, must begin with `X_`. +3. All functions and global variables defined in the script and its configuration, must begin with `X_`. -4. The following functions must be defined: +4. The following functions must be defined: - - `X_check()` - returns 0 or 1 depending on whether the module is able to run or not + - `X_check()` - returns 0 or 1 depending on whether the module is able to run or not (following the standard Linux command line return codes: 0 = OK, the collector can operate and 1 = FAILED, the collector cannot be used). - - `X_create()` - creates the Netdata charts, following the standard Netdata plugin guides as described in - **[External Plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md)** (commands `CHART` and `DIMENSION`). + - `X_create()` - creates the Netdata charts (commands `CHART` and `DIMENSION`). The return value does matter: 0 = OK, 1 = FAILED. - - `X_update()` - collects the values for the defined charts, following the standard Netdata plugin guides - as described in **[External Plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md)** (commands `BEGIN`, `SET`, `END`). + - `X_update()` - collects the values for the defined charts (commands `BEGIN`, `SET`, `END`). The return value also matters: 0 = OK, 1 = FAILED. -5. The following global variables are available to be set: - - `X_update_every` - is the data collection frequency for the module script, in seconds. +5. The following global variables are available to be set: + - `X_update_every` - is the data collection frequency for the module script, in seconds. The module script may use more functions or variables. But all of them must begin with `X_`. -The standard Netdata plugin variables are also available (check **[External Plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md)**). - ### X_check() The purpose of the BASH function `X_check()` is to check if the module can collect data (or check its config). @@ -90,7 +78,7 @@ connect to a local mysql database to find out if it can read the values it needs ### X_create() The purpose of the BASH function `X_create()` is to create the charts and dimensions using the standard Netdata -plugin guides (**[External Plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md)**). +plugin guidelines. `X_create()` will be called just once and only after `X_check()` was successful. You can however call it yourself when there is need for it (for example to add a new dimension to an existing chart). @@ -100,7 +88,7 @@ A non-zero return value will disable the collector. ### X_update() `X_update()` will be called repeatedly every `X_update_every` seconds, to collect new values and send them to Netdata, -following the Netdata plugin guides (**[External Plugins](https://github.com/netdata/netdata/blob/master/collectors/plugins.d/README.md)**). +following the Netdata plugin guidelines. The function will be called with one parameter: microseconds since the last time it was run. This value should be appended to the `BEGIN` statement of every chart updated by the collector script. @@ -187,16 +175,14 @@ You can have multiple `charts.d.plugin` running to overcome this problem. This is what you need to do: -1. Decide a new name for the new charts.d instance: example `charts2.d`. +1. Decide a new name for the new charts.d instance: example `charts2.d`. -2. Create/edit the files `/etc/netdata/charts.d.conf` and `/etc/netdata/charts2.d.conf` and enable / disable the +2. Create/edit the files `/etc/netdata/charts.d.conf` and `/etc/netdata/charts2.d.conf` and enable / disable the module you want each to run. Remember to set `enable_all_charts="no"` to both of them, and enable the individual modules for each. -3. link `/usr/libexec/netdata/plugins.d/charts.d.plugin` to `/usr/libexec/netdata/plugins.d/charts2.d.plugin`. +3. link `/usr/libexec/netdata/plugins.d/charts.d.plugin` to `/usr/libexec/netdata/plugins.d/charts2.d.plugin`. Netdata will spawn a new charts.d process. Execute the above in this order, since Netdata will (by default) attempt to start new plugins soon after they are created in `/usr/libexec/netdata/plugins.d/`. - - |