Add vstorage write usage metrics

[siarhei-agoric]

What is the Problem Being Solved?

We need to be able to monitor how much is being written into vstorage.

Description of the Design

1. create necessary APIs using existing cosmos telemetry infrastructure: https://github.com/agoric-labs/cosmos-sdk/blob/Agoric/docs/core/telemetry.md
2. change Receive() in vstorage.go to capture and feed necessary metrics to cosmos telemetry for set, legacySet, setWithoutNotify, and append

   agoric-sdk/golang/cosmos/x/vstorage/vstorage.go

   Lines 44 to 241 in 9f48684

   	func (sh vstorageHandler) Receive(cctx context.Context, str string) (ret string, err error) {
   	ctx := sdk.UnwrapSDKContext(cctx)
   	keeper := sh.keeper
   	msg := new(vstorageMessage)
   	err = json.Unmarshal([]byte(str), &msg)
   	if err != nil {
   	return
   	}
   	// Allow recovery from OutOfGas panics so that we don't crash
   	defer func() {
   	if r := recover(); r != nil {
   	switch rType := r.(type) {
   	case sdk.ErrorOutOfGas:
   	err = fmt.Errorf(
   	"out of gas in location: %v; gasUsed: %d",
   	rType.Descriptor, ctx.GasMeter().GasConsumed(),
   	)
   	default:
   	// Not ErrorOutOfGas, so panic again.
   	panic(r)
   	}
   	}
   	}()
   	// Handle generic paths.
   	switch msg.Method {
   	case "set":
   	for _, arg := range msg.Args {
   	var entry agoric.KVEntry
   	err = json.Unmarshal(arg, &entry)
   	if err != nil {
   	return
   	}
   	keeper.SetStorageAndNotify(ctx, entry)
   	}
   	return "true", nil
   	// We sometimes need to use LegacySetStorageAndNotify, because the solo's
   	// chain-cosmos-sdk.js consumes legacy events for `mailbox.*` and `egress.*`.
   	// FIXME: Use just "set" and remove this case.
   	case "legacySet":
   	for _, arg := range msg.Args {
   	var entry agoric.KVEntry
   	err = json.Unmarshal(arg, &entry)
   	if err != nil {
   	return
   	}
   	//fmt.Printf("giving Keeper.SetStorage(%s) %s\n", entry.Path(), entry.Value())
   	keeper.LegacySetStorageAndNotify(ctx, entry)
   	}
   	return "true", nil
   	case "setWithoutNotify":
   	for _, arg := range msg.Args {
   	var entry agoric.KVEntry
   	err = json.Unmarshal(arg, &entry)
   	if err != nil {
   	return
   	}
   	keeper.SetStorage(ctx, entry)
   	}
   	return "true", nil
   	case "append":
   	for _, arg := range msg.Args {
   	var entry agoric.KVEntry
   	err = json.Unmarshal(arg, &entry)
   	if err != nil {
   	return
   	}
   	if !entry.HasValue() {
   	err = fmt.Errorf("no value for append entry with path: %q", entry.Key())
   	return
   	}
   	err = keeper.AppendStorageValueAndNotify(ctx, entry.Key(), entry.StringValue())
   	if err != nil {
   	return
   	}
   	}
   	return "true", nil
   	case "get":
   	// Note that "get" does not (currently) unwrap a StreamCell.
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	entry := keeper.GetEntry(ctx, path)
   	bz, err := json.Marshal(entry.Value())
   	if err != nil {
   	return "", err
   	}
   	return string(bz), nil
   	case "getStoreKey":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	value := vstorageStoreKey{
   	StoreName: keeper.GetStoreName(),
   	StoreSubkey: string(keeper.PathToEncodedKey(path)),
   	DataPrefixBytes: string(keeper.GetDataPrefix()),
   	NoDataValue: string(keeper.GetNoDataValue()),
   	}
   	bz, err := json.Marshal(value)
   	if err != nil {
   	return "", err
   	}
   	return string(bz), nil
   	case "has":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	value := keeper.HasStorage(ctx, path)
   	if !value {
   	return "false", nil
   	}
   	return "true", nil
   	// TODO: "keys" is deprecated
   	case "children", "keys":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	children := keeper.GetChildren(ctx, path)
   	if children.Children == nil {
   	return "[]", nil
   	}
   	bytes, err := json.Marshal(children.Children)
   	if err != nil {
   	return "", err
   	}
   	return string(bytes), nil
   	case "entries":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	children := keeper.GetChildren(ctx, path)
   	entries := make([]agoric.KVEntry, len(children.Children))
   	for i, child := range children.Children {
   	entry := keeper.GetEntry(ctx, fmt.Sprintf("%s.%s", path, child))
   	if !entry.HasValue() {
   	entries[i] = agoric.NewKVEntryWithNoValue(child)
   	} else {
   	entries[i] = agoric.NewKVEntry(child, entry.StringValue())
   	}
   	}
   	bytes, err := json.Marshal(entries)
   	if err != nil {
   	return "", err
   	}
   	return string(bytes), nil
   	case "values":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	children := keeper.GetChildren(ctx, path)
   	vals := make([]*string, len(children.Children))
   	for i, child := range children.Children {
   	vals[i] = keeper.GetEntry(ctx, fmt.Sprintf("%s.%s", path, child)).Value()
   	}
   	bytes, err := json.Marshal(vals)
   	if err != nil {
   	return "", err
   	}
   	return string(bytes), nil
   	case "size":
   	var path string
   	err = unmarshalSinglePathFromArgs(msg.Args, &path)
   	if err != nil {
   	return
   	}
   	children := keeper.GetChildren(ctx, path)
   	if children.Children == nil {
   	return "0", nil
   	}
   	return fmt.Sprint(len(children.Children)), nil
   	}
   	return "", errors.New("Unrecognized msg.Method " + msg.Method)
   	}

Security Considerations

TBD

Scaling Considerations

TBD

Test Plan

Manual testing to observe new slog entries for an appropriate pre-existing test case

Upgrade Considerations

TBD

[toliaqat]

@siarhei-agoric can you please share what approach you are taking to get vstorage metrics?

[siarhei-agoric]

@siarhei-agoric can you please share what approach you are taking to get vstorage metrics?

Yes. Please see updated Description of the Design section in the OP.