Jim
8d6dee09a9
* refact: Changes required for gorm v2 * refact: Add db.DB wrapper and refact all test fixtures to use it Stop leaking the gorm abstraction within our unit tests. * refact: Migrate direct calls to pq to pgx driver The refactor will remove the remaining direct dependencies on the pq driver which has been deprecated in favor of the pgx driver. It includes the addition of common.SqlOpen which is a wrapper around sql.Open, which is needed to deal with the driver name changing from "postgres" to "pgx" but in our code base the dialect and driver are synonyms.
oplog
oplog is a package for writing operation log (oplog) entries for the purpose of replication and verification of the data stored in the Boundary RDBMS.
Usage
// you must init the ticket in its own transaction. You only need
// to init a ticket once in the database. It doesn't need to happen for
// every connection. Once it's persistent in the database, you can simply Get it.
initTx := db.Begin()
ticketer := &GormTicketer{Tx: initTx}
err = ticketer.InitTicket("users")
// if there's no error, then commit the initialized ticket
initTx.Commit()
userCreate := oplog_test.TestUser{
TestUser: oplog_test.TestUser{
Name: loginName,
},
}
tx := db.Begin()
// write the user to the database
tx.Create(&userCreate)
ticketer = &GormTicketer{Tx: db}
// get a ticket for writing users to the oplog
ticket, err := ticketer.GetTicket("users")
// create an entry for the oplog with the entry's metadata (likely the entry's Scope)
newLogEntry := NewEntry(
"test-users",
[]Metadata{
Metadata{
Key: "deployment",
Value: "amex",
},
Metadata{
Key: "project",
Value: "central-info-systems",
},
},
cipherer, // wrapping.Wrapper
ticketer,
)
// write an entry with N messages (variadic parameter) in the order they were sent to the database
_, err = newLogEntry.WriteEntryWith(
context.Background(),
&GormWriter{tx},
ticket,
&Message{Message: &userCreate, TypeName: "user", OpType: OpType_CREATE_OP},
)
// if there's an error writing the oplog then roll EVERYTHING back
if err != nil {
tx.Rollback()
}
// no err means you can commit all the things.
tx.Commit()
TBD/TODO
We need to discuss and decide how Boundary is going to handle the following oplog things:
- SQL migrations: you'll find the package's SQL migrations under: ./db/schema We need to decide how Boundary will manage migrations across the system and we will likely need to reference this package's migrations somehow.
oplog entry
Example Oplog Entry for the Target Aggregate
┌────────────────────────────────────────────────┐
│ FIFO with []byte buffer │
│ │
│┌─Msg 4────┐┌─Msg 3────┐┌─Msg 2────┐ │
││ ││ ││ │ │
││ Tags ││ Host ││ HostSet │ │
││┌────────┐││┌────────┐││┌────────┐│ │
│││ ││││ ││││ ││ │
│││ ││││ ││││ ││ │
│││ Tag ││││ Host ││││HostSet ││ │
│││protobuf││││protobuf││││protobuf││ │
│││ ││││ ││││ ││ │
│││ ││││ ││││ ││ │
││└────────┘││└────────┘││└────────┘│ │
││┌────────┐││┌────────┐││┌────────┐│ │
│││ ││││ ││││ ││ │
│││typeName││││typeName││││typeName││ │
│││ Tag ││││ Host ││││HostSet ││ │
││└────────┘││└────────┘││└────────┘│ │
││┌────────┐││┌────────┐││┌────────┐│ │
│││ ││││ ││││ ││ │
│││ OpType ││││ OpType ││││ OpType ││ │
│││ Create ││││ Create ││││ Create ││ │
││└────────┘││└────────┘││└────────┘│ │
│└──────────┘└──────────┘└──────────┘ │
└────────────────────────────────────────────────┘
oplog tables
oplog tables:
as the diagram shows, we can split the
oplog_entries into multiple tables if
needed for performance.
┌────────────────┐
│┌───────────────┴┐
││┌───────────────┴┐ ┌────────────────┐
│││ oplog_entries │ │ oplog_ticket │
││├────────────────┤ ├────────────────┤
│││id │╲ │id │
│││aggregate_name │──┼───────┼ │aggregate_name │
└┤│data │╱ │version │
└┤ │ │ │
└────────────────┘ └────────────────┘
┼
│
│
┼
╱│╲
┌────────────────┐
│ oplog_metadata │
├────────────────┤
│id │
│entry_id │
│key │
│value │
└────────────────┘
oplog optimistic locking using tickets
Alice's Database
transaction Bob's transaction
│ │ │
│─────────BEGIN──────────────────▶│ │
│ │◀───────────────BEGIN─────────────────┤
│ ┌───────────┴───────────┐ │
│ │ ticket version:1 │ │
│ └───────────┬───────────┘ │
│ Select oplog-ticket for │ │
├──────────────"Target"──────────▶│ Select oplog-ticket for │
│ │◀──────────────"Target"───────────────┤
│ │ │
│ Write to Tables in │ │
├───────Target Aggregate─────────▶│ │
│ │ Write to Tables in │
│ │◀─────────Target Aggregate────────────┤
│ │ │
│ │ │
│ Update Ticket │ │
├────Version = 2 where───────────▶│ │
│ Version = 1 ┌─────────┴─────────┐ │
│ │ ticket version: 2 │ │
│ └─────────┬─────────┘ │
│ │ Update Ticket │
│ │◀───────────Version = 2 where─────────┤
│ │ Version = 1 ┌────┴──────────┐
│ │ │ update failed │
├────────────Commit──────────────▶│ └────┬──────────┘
│ │ │
│ │ │
│ │ │
│ │◀────────────Rollback─────────────────┤
│ │ │
│ │ │
```