[MariemBaccari]

This PR extracts the work of #1587 to implement protobuf based encoding of the proposal envelope (part of #1709). The previous PR used binary encoding but protobuf is a simplification that only adds a few bytes to each payload.
Follow-up PRs will implement compression and custom encoding for the payload values which will further reduce the payload size.

A small experiment shows the size difference between the json and protobuf encodings:

Case	Cells	Payload (B)	JSON envelope (B)	Protobuf envelope (B)	Saved
RID delete ISA	-	75	276	145	47.5%
SCD delete OIR	-	213	461	285	38.2%
RID create ISA	1	275	544	346	36.4%
RID create ISA	10	455	784	526	32.9%
RID create ISA	100	2255	3184	2326	26.9%
RID create ISA	1000	20255	27184	20327	25.2%
RID create subscription	1	310	579	368	36.4%
RID create subscription	10	490	819	548	33.1%
RID create subscription	100	2290	3219	2348	27.1%
RID create subscription	1000	20290	27219	20349	25.2%
SCD create subscription	1	384	675	442	34.5%
SCD create subscription	10	564	915	622	32.0%
SCD create subscription	100	2364	3315	2422	26.9%
SCD create subscription	1000	20364	27315	20423	25.2%
SCD create constraint	1	296	566	361	36.2%
SCD create constraint	10	476	806	541	32.9%
SCD create constraint	100	2276	3206	2341	27.0%
SCD create constraint	1000	20276	27206	20342	25.2%
SCD create OIR	1	466	801	538	32.8%
SCD create OIR	10	646	1041	718	31.0%
SCD create OIR	100	2446	3441	2518	26.8%
SCD create OIR	1000	20446	27441	20519	25.2%

[mickmis]

Consider passing the go version as an argument from the makefile:

• in general we will this version to be >= version in the go.mod
• there are several other places where a go version is specified that would be good to be kept in sync (e.g. openapi-to-go-server, test-certs, dummy-oauth, etc.). Not necessarily in this PR, but that would at least prepare the ground work for that (drop a TODO comment if not implemented in this PR)

[mickmis]

Have you checked the validity of this regarding timezones?
IIUC tz info is lost after decoding here, but it might be irrelevant (e.g. always set to UTC, tz are never taken into account, etc.)
In any case: it is worth a check and an explicit clarification somewhere somehow. Especially since I expect different nodes to operate in different timezones in our case.

[MariemBaccari]

I just added a comment to clarify that the timestamp is always set to UTC to avoid this 👍

[MariemBaccari]

This feedback under #1775 should be addressed in this PR.

[mickmis]

LGTM

Second thoughts

[mickmis]

Discussed offline:

• actually define the payload as a proto message with a oneof replacing request_type and value
• proto files in interfaces root folder

Example:

syntax = "proto3";

package dss.raftstore.consensus;

import "google/protobuf/timestamp.proto";

option go_package = "github.com/interuss/dss/pkg/raftstore/consensus/proposalpb";

// in interfaces

message UpsertOperationalIntent {
    string id = 1;
    string manager = 2;
    // etc. ...
}

message SearchOperationalIntents {
    google.protobuf.Timestamp start = 2;
    // etc. ...
}

message Proposal {
    bytes id = 1;
    uint64 node_id = 2;
    google.protobuf.Timestamp timestamp = 3;
    oneof payload {
        UpsertOperationalIntent UpsertOperationalIntent = 10;
        SearchOperationalIntents searchOperationalIntents = 11;
        // etc.
    }
//    string request_type = 4; // replaced by payload
//    bytes value = 5; // replaced by payload
//    bool read_only = 6; // could be inferred replaced by payload maybe?
}

[MariemBaccari]

Considering @mickmis 's feedback, I'm closing this PR.