feat: Allow app developers to override default appConfig template (co…

…smos#9550)

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## Description

Closes: cosmos#5540

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---

### Author Checklist

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please add links to any relevant follow up issues.*

I have...

- [x] 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
- [x] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] 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`
- [x] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [x] updated the relevant documentation or specification
- [x] reviewed "Files changed" and left comments if necessary
- [x] confirmed all CI checks have passed

### Reviewers Checklist

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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)

simd/cmd/root.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 
+	serverconfig "github.com/cosmos/cosmos-sdk/server/config"
 	"github.com/spf13/cast"
 	"github.com/spf13/cobra"
 	tmcli "github.com/tendermint/tendermint/libs/cli"
@@ -14,7 +15,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/baseapp"
 	"github.com/cosmos/cosmos-sdk/client"
-	config "github.com/cosmos/cosmos-sdk/client/config"
+	"github.com/cosmos/cosmos-sdk/client/config"
 	"github.com/cosmos/cosmos-sdk/client/debug"
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	"github.com/cosmos/cosmos-sdk/client/keys"
@@ -66,7 +67,9 @@ func NewRootCmd() (*cobra.Command, params.EncodingConfig) {
 				return err
 			}
 
-			return server.InterceptConfigsPreRunHandler(cmd)
+			customAppTemplate, customAppConfig := initAppConfig()
+
+			return server.InterceptConfigsPreRunHandler(cmd, customAppTemplate, customAppConfig)
 		},
 	}
 
@@ -75,6 +78,45 @@ func NewRootCmd() (*cobra.Command, params.EncodingConfig) {
 	return rootCmd, encodingConfig
 }
 
+// initAppConfig helps to override default appConfig template and configs.
+// return "", nil if no custom configuration is required for the application.
+func initAppConfig() (string, interface{}) {
+	// The following code snippet is just for reference.
+
+	// WASMConfig defines configuration for the wasm module.
+	type WASMConfig struct {
+		// This is the maximum sdk gas (wasm and storage) that we allow for any x/wasm "smart" queries
+		QueryGasLimit uint64 `mapstructure:"query_gas_limit"`
+
+		// Address defines the gRPC-web server to listen on
+		LruSize uint64 `mapstructure:"lru_size"`
+	}
+
+	type CustomAppConfig struct {
+		serverconfig.Config
+
+		WASM WASMConfig `mapstructure:"wasm"`
+	}
+
+	customAppConfig := CustomAppConfig{
+		Config: *serverconfig.DefaultConfig(),
+		WASM: WASMConfig{
+			LruSize:       1,
+			QueryGasLimit: 300000,
+		},
+	}
+
+	customAppTemplate := serverconfig.DefaultConfigTemplate + `
+[wasm]
+# This is the maximum sdk gas (wasm and storage) that we allow for any x/wasm "smart" queries
+query_gas_limit = 300000
+# This is the number of wasm vm instances we keep cached in memory for speed-up
+# Warning: this is currently unstable and may lead to crashes, best to keep for 0 unless testing locally
+lru_size = 0`
+
+	return customAppTemplate, customAppConfig
+}
+
 func initRootCmd(rootCmd *cobra.Command, encodingConfig params.EncodingConfig) {
 	cfg := sdk.GetConfig()
 	cfg.Seal()