// retrieveMetrics contacts the attached gexp node and retrieves the entire set
// of collected system metrics.
func retrieveMetrics(client rpc.Client) (map[string]interface{}, error) {
req := map[string]interface{}{
"id": new(int64),
"method": "debug_metrics",
"jsonrpc": "2.0",
"params": []interface{}{true},
}
if err := client.Send(req); err != nil {
return nil, err
}
var res rpc.JSONSuccessResponse
if err := client.Recv(&res); err != nil {
return nil, err
}
if res.Result != nil {
if mets, ok := res.Result.(map[string]interface{}); ok {
return mets, nil
}
}
return nil, fmt.Errorf("unable to retrieve metrics")
}
// monitor starts a terminal UI based monitoring tool for the requested metrics.
func monitor(ctx *cli.Context) error {
var (
client rpc.Client
err error
)
// Attach to an Expanse node over IPC or RPC
endpoint := ctx.String(monitorCommandAttachFlag.Name)
if client, err = utils.NewRemoteRPCClientFromString(endpoint); err != nil {
utils.Fatalf("Unable to attach to gexp node: %v", err)
}
defer client.Close()
// Retrieve all the available metrics and resolve the user pattens
metrics, err := retrieveMetrics(client)
if err != nil {
utils.Fatalf("Failed to retrieve system metrics: %v", err)
}
monitored := resolveMetrics(metrics, ctx.Args())
if len(monitored) == 0 {
list := expandMetrics(metrics, "")
sort.Strings(list)
if len(list) > 0 {
utils.Fatalf("No metrics specified.\n\nAvailable:\n - %s", strings.Join(list, "\n - "))
} else {
utils.Fatalf("No metrics collected by gexp (--%s).\n", utils.MetricsEnabledFlag.Name)
}
}
sort.Strings(monitored)
if cols := len(monitored) / ctx.Int(monitorCommandRowsFlag.Name); cols > 6 {
utils.Fatalf("Requested metrics (%d) spans more that 6 columns:\n - %s", len(monitored), strings.Join(monitored, "\n - "))
}
// Create and configure the chart UI defaults
if err := termui.Init(); err != nil {
utils.Fatalf("Unable to initialize terminal UI: %v", err)
}
defer termui.Close()
rows := len(monitored)
if max := ctx.Int(monitorCommandRowsFlag.Name); rows > max {
rows = max
}
cols := (len(monitored) + rows - 1) / rows
for i := 0; i < rows; i++ {
termui.Body.AddRows(termui.NewRow())
}
// Create each individual data chart
footer := termui.NewPar("")
footer.Block.Border = true
footer.Height = 3
charts := make([]*termui.LineChart, len(monitored))
units := make([]int, len(monitored))
data := make([][]float64, len(monitored))
for i := 0; i < len(monitored); i++ {
charts[i] = createChart((termui.TermHeight() - footer.Height) / rows)
row := termui.Body.Rows[i%rows]
row.Cols = append(row.Cols, termui.NewCol(12/cols, 0, charts[i]))
}
termui.Body.AddRows(termui.NewRow(termui.NewCol(12, 0, footer)))
refreshCharts(client, monitored, data, units, charts, ctx, footer)
termui.Body.Align()
termui.Render(termui.Body)
// Watch for various system events, and periodically refresh the charts
termui.Handle("/sys/kbd/C-c", func(termui.Event) {
termui.StopLoop()
})
termui.Handle("/sys/wnd/resize", func(termui.Event) {
termui.Body.Width = termui.TermWidth()
for _, chart := range charts {
chart.Height = (termui.TermHeight() - footer.Height) / rows
}
termui.Body.Align()
termui.Render(termui.Body)
})
go func() {
tick := time.NewTicker(time.Duration(ctx.Int(monitorCommandRefreshFlag.Name)) * time.Second)
for range tick.C {
if refreshCharts(client, monitored, data, units, charts, ctx, footer) {
termui.Body.Align()
}
termui.Render(termui.Body)
}
}()
termui.Loop()
return nil
}