feat: customtendermint config (#11049)

## Description

Closes: https://github.com/cosmos/cosmos-sdk/issues/10936

avoid copy pasting init command, allow teams to overwrite config by default. 

another feature proposal

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

CHANGELOG.md

@@ -219,6 +219,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * [\#10561](https://github.com/cosmos/cosmos-sdk/pull/10561) The `CommitMultiStore` interface contains a new `SetIAVLCacheSize` method
 * [\#10922](https://github.com/cosmos/cosmos-sdk/pull/10922), [/#10956](https://github.com/cosmos/cosmos-sdk/pull/10956) Deprecate key `server.Generate*` functions and move them to `testutil` and support custom mnemonics in in-process testing network. Moved `TestMnemonic` from `testutil` package to `testdata`.
+* [\#11049](https://github.com/cosmos/cosmos-sdk/pull/11049) Add custom tendermint config variables into root command. Allows App developers to set config.toml variables. 
 
 ### Features
 

server/util.go

@@ -105,7 +105,7 @@ func bindFlags(basename string, cmd *cobra.Command, v *viper.Viper) (err error)
 // is used to read and parse the application configuration. Command handlers can
 // fetch the server Context to get the Tendermint configuration or to get access
 // to Viper.
-func InterceptConfigsPreRunHandler(cmd *cobra.Command, customAppConfigTemplate string, customAppConfig interface{}) error {
+func InterceptConfigsPreRunHandler(cmd *cobra.Command, customAppConfigTemplate string, customAppConfig interface{}, tmConfig *tmcfg.Config) error {
 	serverCtx := NewDefaultContext()
 
 	// Get the executable name and configure the viper instance so that environmental
@@ -126,7 +126,7 @@ func InterceptConfigsPreRunHandler(cmd *cobra.Command, customAppConfigTemplate s
 	serverCtx.Viper.AutomaticEnv()
 
 	// intercept configuration files, using both Viper instances separately
-	config, err := interceptConfigs(serverCtx.Viper, customAppConfigTemplate, customAppConfig)
+	config, err := interceptConfigs(serverCtx.Viper, customAppConfigTemplate, customAppConfig, tmConfig)
 	if err != nil {
 		return err
 	}
@@ -184,12 +184,12 @@ func SetCmdServerContext(cmd *cobra.Command, serverCtx *Context) error {
 // configuration file. The Tendermint configuration file is parsed given a root
 // Viper object, whereas the application is parsed with the private package-aware
 // viperCfg object.
-func interceptConfigs(rootViper *viper.Viper, customAppTemplate string, customConfig interface{}) (*tmcfg.Config, error) {
+func interceptConfigs(rootViper *viper.Viper, customAppTemplate string, customConfig interface{}, tmConfig *tmcfg.Config) (*tmcfg.Config, error) {
 	rootDir := rootViper.GetString(flags.FlagHome)
 	configPath := filepath.Join(rootDir, "config")
 	tmCfgFile := filepath.Join(configPath, "config.toml")
 
-	conf := tmcfg.DefaultConfig()
+	conf := tmConfig
 
 	switch _, err := os.Stat(tmCfgFile); {
 	case os.IsNotExist(err):

server/util_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/require"
+	tmcfg "github.com/tendermint/tendermint/config"
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/client/flags"
@@ -27,7 +28,7 @@ var cancelledInPreRun = errors.New("Cancelled in prerun")
 // Used in each test to run the function under test via Cobra
 // but to always halt the command
 func preRunETestImpl(cmd *cobra.Command, args []string) error {
-	err := server.InterceptConfigsPreRunHandler(cmd, "", nil)
+	err := server.InterceptConfigsPreRunHandler(cmd, "", nil, tmcfg.DefaultConfig())
 	if err != nil {
 		return err
 	}
@@ -432,7 +433,7 @@ func TestEmptyMinGasPrices(t *testing.T) {
 	// Run StartCmd.
 	cmd = server.StartCmd(nil, tempDir)
 	cmd.PreRunE = func(cmd *cobra.Command, _ []string) error {
-		return server.InterceptConfigsPreRunHandler(cmd, "", nil)
+		return server.InterceptConfigsPreRunHandler(cmd, "", nil, tmcfg.DefaultConfig())
 	}
 	err = cmd.ExecuteContext(ctx)
 	require.Errorf(t, err, sdkerrors.ErrAppConfig.Error())

simapp/simd/cmd/root.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/spf13/cast"
 	"github.com/spf13/cobra"
+	tmcfg "github.com/tendermint/tendermint/config"
 	tmcli "github.com/tendermint/tendermint/libs/cli"
 	"github.com/tendermint/tendermint/libs/log"
 	dbm "github.com/tendermint/tm-db"
@@ -71,8 +72,9 @@ func NewRootCmd() (*cobra.Command, params.EncodingConfig) {
 			}
 
 			customAppTemplate, customAppConfig := initAppConfig()
+			customTMConfig := initTendermintConfig()
 
-			return server.InterceptConfigsPreRunHandler(cmd, customAppTemplate, customAppConfig)
+			return server.InterceptConfigsPreRunHandler(cmd, customAppTemplate, customAppConfig, customTMConfig)
 		},
 	}
 
@@ -81,6 +83,18 @@ func NewRootCmd() (*cobra.Command, params.EncodingConfig) {
 	return rootCmd, encodingConfig
 }
 
+// initTendermintConfig helps to override default Tendermint Config values.
+// return tmcfg.DefaultConfig if no custom configuration is required for the application.
+func initTendermintConfig() *tmcfg.Config {
+	cfg := tmcfg.DefaultConfig()
+
+	// these values put a higher strain on node memory
+	// cfg.P2P.MaxNumInboundPeers = 100
+	// cfg.P2P.MaxNumOutboundPeers = 40
+
+	return cfg
+}
+
 // initAppConfig helps to override default appConfig template and configs.
 // return "", nil if no custom configuration is required for the application.
 func initAppConfig() (string, interface{}) {