# RRD {% hint style="info" %} rrd plugins requires TINE to be built with `-tags rrd` which need `librrd-dev` package to be installed in advance. {% endhint %} Let's create an example application that collects CPU usage and system load average, saves the data into RRD, and serves a web page that displays the collected data as graphs. The code provided starts a simple web server that listens on `http://127.0.0.1:8080` and exposes three endpoints: `/`, `/graph/load`, and `/graph/cpu`. ### Code Please find the complete source code in the [GitHub repository](https://github.com/OutOfBedlam/tine/tree/main/example/rrd_graph_web). ```go package main import ( "fmt" "net/http" "github.com/OutOfBedlam/tine/engine" _ "github.com/OutOfBedlam/tine/plugins/all" _ "github.com/OutOfBedlam/tine/x/rrd" ) func main() { addr := "127.0.0.1:8080" // start data collector that save metrics to rrd file collect, _ := engine.New(engine.WithConfig(collectorPipeline)) collect.Start() router := http.NewServeMux() router.HandleFunc("GET /", getView) router.HandleFunc("GET /graph/load", HttpHandler(graphLoadPipeline)) router.HandleFunc("GET /graph/cpu", HttpHandler(graphCpuPipeline)) fmt.Printf("\nlistener start at http://%s\n", addr) http.ListenAndServe(addr, router) // stop data collector collect.Stop() } ``` ### Run Create a file named `rrd_graph_web.go` with the provided code and build it using the `-tags rrd` build flags. ```sh go run --tags rrd ./rrd_graph_web.go ``` Then open a web browser to view the graphs displaying the system's load average and CPU usage.

### How this works #### Start collecting pipeline Make a pipeline that collecting CPU usage and load average and merge them into a record then writing on the RRD file. ```go collect, _ := engine.New(engine.WithConfig(collectorPipeline)) collect.Start() ...omit... collect.Stop() ``` In the `collectorPipeline` pipeline, the `inlets.cpu` and `inlets.load` collect CPU usage and load average data respectively. The `flows.merge` merges the collected data into a single record. The `outlets.rrd` writes the merged data to the RRD file specified by the `path` parameter. You can customize the pipeline configuration according to your requirements. Make sure to adjust the `path` parameter in the `outlets.rrd` section to specify the desired location for the RRD file. The pipeline is defined as: ```toml name = "rrd-collector" [defaults] interval = "1s" [[inlets.load]] [[inlets.cpu]] percpu = false totalcpu = true [[flows.merge]] wait_limit = "2s" name_infix = "." [[outlets.rrd]] path = "./tmp/rrdweb.rrd" step = "1s" heartbeat = "2s" fields = [ { field="load.load1", ds="load1", dst="GAUGE", min=0.0, max="U" }, { field="load.load5", ds="load5", dst="GAUGE", min=0.0, max="U" }, { field="load.load15", ds="load15", dst="GAUGE", min=0.0, max="U" }, { field="cpu.total_percent", ds="cpu_total", dst="GAUGE", min=0.0, max="U" }, ] rra = [ { cf = "AVERAGE", steps = "1s", rows="3h" }, { cf = "AVERAGE", steps = "1m", rows="3d" }, { cf = "AVERAGE", steps = "1h", rows="30d" }, { cf = "AVERAGE", steps = "1d", rows="13M" }, ] ``` #### Rendering HTML Attach the `getView` handler to the `/` endpoint. ```go router.HandleFunc("GET /", getView) ``` The `getView()` handler embeds two `` elements that runs on endpoints, `/graph/load` and `/graph/cpu`, and reloads them every 2 seconds. ```go func getView(w http.ResponseWriter, r *http.Request) { w.Header().Set("Content-Type", "text/html") w.Write([]byte(`

`)) } ``` #### HttpHandler wrapper for a pipeline Running a pipeline as a HTTP Handler requires preparation, the below `HttpHandler()` code shows how to wrap your pipeline for a handle. ```go func HttpHandler(config string) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { p, _ := engine.New( engine.WithConfig(config), engine.WithWriter(w), ) if err := p.Run(); err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) return } p.Stop() } } ``` #### Attach pipelines to the endpoints ```go router.HandleFunc("GET /graph/load", HttpHandler(graphLoadPipeline)) router.HandleFunc("GET /graph/cpu", HttpHandler(graphCpuPipeline)) ``` The pipeline definitions of `graphLoadPipeline` and `graphCpuPipeline` are: **graphLoadPipeline** ```toml name = "rrdweb-load" [[inlets.rrd_graph]] path = "./tmp/rrdweb.rrd" count = 1 title = "System Load" range = "10m" size = [600, 200] theme = "gchart2" fields = [ { ds = "load1", cf="AVERAGE", type="line", name="%-6s", min="%3.1lf", max="%3.1lf", avg="%3.1lf", last="%3.1lf\\n"}, { ds = "load5", cf="AVERAGE", type="line", name="%-6s", min="%3.1lf", max="%3.1lf", avg="%3.1lf", last="%3.1lf\\n"}, { ds = "load15", cf="AVERAGE", type="area", name="%-6s", min="%3.1lf", max="%3.1lf", avg="%3.1lf", last="%3.1lf\\n"}, ] [[outlets.image]] path = "nonamed.png" ``` **graphCpuPipeline** ```toml name = "rrdweb-cpu" [[inlets.rrd_graph]] path = "./tmp/rrdweb.rrd" count = 1 title = "CPU Usage (%)" range = "10m" size = [600, 200] theme = "gchart2" fields = [ { ds = "cpu_total", cf="AVERAGE", type="line", name="%-6s", min="%3.1lf", max="%3.1lf", avg="%3.1lf", last="%3.1lf\\n"}, ] [[outlets.image]] path = "nonamed.png" ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://tine.thingsme.xyz/recipes/rrd.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.