logging: implement lazy sprinting (#8898)

shout out to @joeabbey for the inspiration. This makes the lazy
functions internal by default to prevent potential misuse by external
callers.

Should backport cleanly into 0.36 and I'll handle a messy merge into 0.35

test/e2e/app/app.go

@@ -18,6 +18,7 @@ import (
 	"github.com/tendermint/tendermint/abci/example/code"
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/crypto"
+	tmstrings "github.com/tendermint/tendermint/internal/libs/strings"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/proto/tendermint/types"
 	"github.com/tendermint/tendermint/version"
@@ -484,7 +485,10 @@ func (app *Application) ExtendVote(_ context.Context, req *abci.RequestExtendVot
 		time.Sleep(time.Duration(app.cfg.VoteExtensionDelayMS) * time.Millisecond)
 	}
 
-	app.logger.Info("generated vote extension", "num", num, "ext", fmt.Sprintf("%x", ext[:extLen]), "state.Height", app.state.Height)
+	app.logger.Info("generated vote extension",
+		"num", num,
+		"ext", tmstrings.LazySprintf("%x", ext[:extLen]),
+		"state.Height", app.state.Height)
 	return &abci.ResponseExtendVote{
 		VoteExtension: ext[:extLen],
 	}, nil

test/e2e/runner/cleanup.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"os"
 
 	"github.com/tendermint/tendermint/libs/log"
@@ -27,6 +26,6 @@ func Cleanup(ctx context.Context, logger log.Logger, testnetDir string, ti infra
 		return err
 	}
 
-	logger.Info(fmt.Sprintf("Removing testnet directory %q", testnetDir))
+	logger.Info("Removing testnet", "directory", testnetDir)
 	return os.RemoveAll(testnetDir)
 }