implemented jeffs nits

cmd/solana_exporter/slots.go

@@ -208,7 +208,7 @@ func (c *SlotWatcher) fetchAndEmitBlockProduction(ctx context.Context, endSlot i
 
 	// make sure the bounds are contained within the epoch we are currently watching:
 	if err := c.checkValidSlotRange(startSlot, endSlot); err != nil {
-		panic(err)
+		klog.Fatalf("invalid slot range: %v", err)
 	}
 
 	// fetch block production:

cmd/solana_exporter/utils.go

@@ -1,25 +1,11 @@
 package main
 
 import (
-	"encoding/json"
-	"fmt"
+	"k8s.io/klog/v2"
 )
 
 func assertf(condition bool, format string, args ...any) {
 	if !condition {
-		panic(fmt.Errorf(format, args...))
+		klog.Fatalf(format, args...)
 	}
 }
-
-// prettyPrint is just a useful debugging function
-func prettyPrint(obj any) {
-	// For pretty-printed JSON, use json.MarshalIndent
-	prettyJSON, err := json.MarshalIndent(obj, "", "  ")
-	if err != nil {
-		fmt.Println("Error marshalling to pretty JSON:", err, ". obj: ", obj)
-		return
-	}
-
-	// Print the pretty JSON string
-	fmt.Println(string(prettyJSON))
-}

pkg/rpc/client.go

@@ -92,14 +92,14 @@ func (c *Client) getResponse(ctx context.Context, method string, params []any, r
 	request := &rpcRequest{Version: "2.0", ID: 1, Method: method, Params: params}
 	buffer, err := json.Marshal(request)
 	if err != nil {
-		panic(err)
+		klog.Fatalf("failed to marshal request: %v", err)
 	}
 	klog.V(2).Infof("jsonrpc request: %s", string(buffer))
 
 	// make request:
 	req, err := http.NewRequestWithContext(ctx, "POST", c.rpcAddr, bytes.NewBuffer(buffer))
 	if err != nil {
-		panic(err)
+		klog.Fatalf("failed to create request: %v", err)
 	}
 	req.Header.Set("content-type", "application/json")
 
@@ -177,7 +177,7 @@ func (c *Client) GetBlockProduction(
 ) (*BlockProduction, error) {
 	// can't provide a last slot without a first:
 	if firstSlot == nil && lastSlot != nil {
-		panic("can't provide a last slot without a first!")
+		klog.Fatalf("can't provide a last slot without a first!")
 	}
 
 	// format params:
@@ -190,7 +190,8 @@ func (c *Client) GetBlockProduction(
 		if lastSlot != nil {
 			// make sure first and last slot are in order:
 			if *firstSlot > *lastSlot {
-				panic(fmt.Errorf("last slot %v is greater than first slot %v", *lastSlot, *firstSlot))
+				err := fmt.Errorf("last slot %v is greater than first slot %v", *lastSlot, *firstSlot)
+				klog.Fatalf("%v", err)
 			}
 			blockRange["lastSlot"] = *lastSlot
 		}