feat(gnovm, tm2): implement event emission with std.Emit

[notJoon]

Description

Succeed in my predecessor's legacy.

I have implemented the output to show the path where the event occurred, as discussed in #1833. Also made it print the timestamp or block height together.

Key Changes

In this change, event emission functionality has been added to the Gno. The main changes include:

1. Introducing of the emitEvent function:

   • The emitEvent function emits an event based on the given type and attributes
   • Attributes are passed as an even-length of array key-value pairs
   • When emitting an event, the current package path, timestamp, and block height information are recorded along with the event(discussed in [chain] Support for on-chain Realm Events #1833). This metadata provides additional context about where the event occured.

2. Additional of event-related types and functions in the sdk packages:

   • NewEvent creates a new Event object based on the provided information.
   • ArributedEvent struct contains informations such as event type, package path, block height, timestamp and attributes. But I'm not sure how to utilize the eventType yet. So, I've just put it as a placeholder which will be a disscussion for another time.
   • EventArribute represents an attribute of an event and consists of a key-value pair
   • NewEventArribute creates a new EventAttribute object based on the given key-value pair.

Example

package ee

import (
	"std"
)

const (
	EventSender = "sender"
	EventReceiver = "receiver"
)

func Sender(){
    SubSender()
    SubReceiver()
}

func SubSender() {
    std.Emit(
        EventSender,
		"key1", "value1",
		"key2", "value2",
		"key3", "value3",
    )  
}

func SubReceiver() {
    std.Emit(
        EventReceiver,
        "bar", "baz",
    )
}

func Receiver() {
    std.Emit(
        EventReceiver,
        "foo", "bar",
    )
}

Result

[
  "{\"type\":\"sender\",\"pkg_path\":\"gno.land/r/demo/ee\",\"identifier\":\"SubSender\",\"timestamp\":1713846501,\"attributes\":[{\"key\":\"key1\",\"value\":\"value1\"},{\"key\":\"key2\",\"value\":\"value2\"},{\"key\":\"key3\",\"value\":\"value3\"}]}",
  "{\"type\":\"receiver\",\"pkg_path\":\"gno.land/r/demo/ee\",\"identifier\":\"SubReceiver\",\"timestamp\":1713846501,\"attributes\":[{\"key\":\"bar\",\"value\":\"baz\"}]}"
]

Related Issue/PR

#575 emit & event built-in functions (@r3v4s)
#853 feat: event & emit in gno (@anarcher) <- previous work.
#975 [META] Gno Wishlist / Feature Request Dump (@zivkovicmilos)

[codecov]

Codecov Report

Attention: Patch coverage is 38.88889% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 46.72%. Comparing base (7bf662a) to head (7a5fd74).
Report is 5 commits behind head on master.

Files	Patch %	Lines
tm2/pkg/bft/abci/types/types.go	0.00%	7 Missing ⚠️
gno.land/pkg/sdk/vm/keeper.go	60.00%	2 Missing ⚠️
tm2/pkg/crypto/keys/client/maketx.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1653      +/-   ##
==========================================
+ Coverage   46.64%   46.72%   +0.08%     
==========================================
  Files         492      492              
  Lines       69624    69762     +138     
==========================================
+ Hits        32476    32597     +121     
- Misses      34442    34454      +12     
- Partials     2706     2711       +5     

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[zivkovicmilos]

Will take a look at this and give feedback 🙏

[notJoon]

Will take a look at this and give feedback 🙏

Thank you @zivkovicmilos! I'm still trying to understand most things, every feedback would be greatly helpful

[zivkovicmilos]

I honestly believe this is the way to go 💯

The solution proposed here is simple, elegant, minimal.
It doesn't force us to modify the transaction result in order to accommodate event data, which I see as a huge plus -- it's completely backwards compatible.

We just need to figure out how to pipe the event emissions from the Gno code (and what the API should be, I'm hoping something within std), and we should be good to go 🚀

[zivkovicmilos]

Approving, again, because the changes are solid

Please check the leftover comments, but don't resolve them on the GitHub UI 🙏
Let the comment author / core team resolve the comment after you reply / ping them as soon as the fix has been pushed

[moul]

Please take into account my previous comment.

[r3v4s]

FYI, for everyone who has been in this PR
Please take a look at this bug #2028