26 releases (12 breaking)
0.17.1 | Jan 26, 2023 |
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0.16.0 | Dec 16, 2022 |
0.15.1 | Sep 22, 2022 |
0.13.0 | Jul 26, 2022 |
0.8.1 | Mar 29, 2022 |
#6 in Magic Beans
87 downloads per month
Used in 12 crates
(9 directly)
47KB
726 lines
TG4 Spec: Group Members
TG4 is a spec for storing group membership, which can be combined with TG3 multisigs. The purpose is to store a set of members/voters that can be accessed to determine permissions in another section.
Since this is often deployed as a contract pair, we expect this
contract to often be queried with QueryRaw
and the internal
layout of some data structures becomes part of the public API.
Implementations may add more data structures, but at least
the ones laid out here should be under the specified keys and in the
same format.
In this case, a tg3 contract could read an external group contract with no significant cost more than reading local storage. However, updating that group contract (if allowed), would be an external message and charged the instantiation overhead for each contract.
Messages
We define an InstantiateMsg{admin, members}
to make it easy to set up a group
as part of another flow. Implementations should work with this setup,
but may add extra Option<T>
fields for non-essential extensions to
configure in the instantiate
phase.
There are three messages supported by a group contract:
UpdateAdmin{admin}
- changes (or clears) the admin for the contract
AddHook{addr}
- adds a contract address to be called upon every
UpdateMembers
call. This can only be called by the admin, and care must
be taken. A contract returning an error or running out of gas will
revert the membership change (see more in Hooks section below).
RemoveHook{addr}
- unregister a contract address that was previously set
by AddHook
.
Only the admin
may execute any of these function. Thus, by omitting an
admin
, we end up with a similar functionality than cw3-fixed-multisig
.
If we include one, it may often be desired to be a tg3
contract that
uses this group contract as a group. This leads to a bit of chicken-and-egg
problem, but we cover how to instantiate that in
cw3-flexible-multisig
.
Queries
Smart
TotalPoints{}
- Returns the total points of all current members,
this is very useful if some conditions are defined on a "percentage of members".
Member{addr, height}
- Returns the points of this voter if they are a member of the
group (may be 0), or None
if they are not a member of the group.
If height is set, and the tg4 implementation supports snapshots,
this will return the points of that member at
the beginning of the block with the given height.
ListMembers{start_after, limit}
- Allows us to paginate over the list
of all members. 0-points members will be included. Removed members will not.
ListMembersByPoints{start_after, limit}
- Allows us to paginate over the list
of members, sorted by descending points.
Admin{}
- Returns the admin
address, or None
if unset.
Raw
In addition to the above "SmartQueries", which make up the public API,
we define two raw queries that are designed for more efficiency
in contract-contract calls. These use keys exported by tg4
TOTAL_KEY
- making a raw query with this key (b"total"
) will return a
JSON-encoded u64
member_key()
- takes an Addr
and returns a key that can be
used for raw query ("\x00\x07members" || addr
). This will return
empty bytes if the member is not inside the group, otherwise a
JSON-encoded MemberInfo
struct, that contains the member points
and optionally their membership start height. Which can be used
for tie breaking between members with the same number of points.
See query.rs for details.
Hooks
One special feature of tg4
contracts is that they allow the admin to
register multiple hooks. These are special contracts that need to react
to changes in the group membership, and this allows them stay in sync.
Again, note this is a powerful ability, and you should only set hooks
to contracts you fully trust; generally some contracts you deployed
alongside the group.
If a contract is registered as a hook on a tg4 contract, then anytime
UpdateMembers
is successfully executed, the hook will receive a handle
call with the following format:
{
"member_changed_hook": {
"diffs": [
{
"addr": "cosmos1y3x7q772u8s25c5zve949fhanrhvmtnu484l8z",
"old_points": 20,
"new_points": 24
}
]
}
}
See hook.rs for full details. Note that this example
shows an update or an existing member. old_points
will
be missing if the address was added for the first time. And
new_points
will be missing if the address was removed.
The receiving contract must be able to handle the MemberChangedHookMsg
and should only return an error if it wants to change the functionality
of the group contract (e.g. a multisig that wants to prevent membership
changes while there is an open proposal). However, such cases are quite
rare and often point to fragile code.
Note that the message sender will be the group contract that was updated. Make sure you check this when handling, so external actors cannot call this hook, only the trusted group.
Dependencies
~3.5–5MB
~109K SLoC