mirror of
https://github.com/hanzoai/tasks.git
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Tim Deeb-SwihartandGitHub
be7b5514a5
## What changed? Both our PostgreSQL and MySQL database backends will now automatically reconnect to the database when certain errors occur: all errors chosen have been experienced when testing this behavior through an AWS Aurora RDS failover of either MySQL or PostgreSQL. For both backends we will reconnect when we see: - `ECONNRESET` - `ECONNABORTED` - `ECONNREFUSED` - `io.EOF` - `io.ErrUnexpectedEOF` - `database/sql/driver.ErrBadConn` for postgres we will also reconnect on the following SQLStates: - `25006` read-only transaction - `57P03` cannot connect now - `0A000` feature not supported, but ONLY when the message is `cannot set transaction read-write mode during recovery` for mysql we will also reconnect when we see the following error codes: - `1040` too many connections - `1792` read-only transaction (SQLstate `25006`) - `1836` running in read-only mode This logic is easily extensible should we discover more failure modes over time ## Why? We've had multiple community reports of Temporal problems during RDS failover. One part of this is the fact that we wouldn't necessarily reconnect; we were at the whims of our chosen SQL abstraction's connection pooling logic. ## How did you test it? I manually tested this functionality in the presence of repeated RDS failovers: - [x] postgres12 plugin with pq driver - [x] postgres12 plugin with pgx driver - [x] mysql plugin Automated testing will be added to our regular testing pipelines once our infrastructure friends have added the support I need (it's in progress) ## Potential risks We're concerned there's a correctness issue in our PostgreSQL backend that's related to our behavior during an RDS failover. If we merge this before I figure out what's going on, we could hide the issue and make it harder to reproduce. ## Documentation N/A ## Is hotfix candidate? Yes?
59 lines
2.1 KiB
Go
59 lines
2.1 KiB
Go
// The MIT License
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//
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// Copyright (c) 2020 Temporal Technologies Inc. All rights reserved.
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//
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// Copyright (c) 2020 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package driver
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import (
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"github.com/jmoiron/sqlx"
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)
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const (
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// check http://www.postgresql.org/docs/9.3/static/errcodes-appendix.html
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dupEntryCode = "23505"
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dupDatabaseCode = "42P04"
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readOnlyTransactionCode = "25006"
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cannotConnectNowCode = "57P03"
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featureNotSupportedCode = "0A000"
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// Unsupported "feature" messages to look for
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cannotSetReadWriteModeDuringRecoveryMsg = "cannot set transaction read-write mode during recovery"
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)
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type Driver interface {
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CreateConnection(dsn string) (*sqlx.DB, error)
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IsDupEntryError(error) bool
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IsDupDatabaseError(error) bool
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IsConnNeedsRefreshError(error) bool
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}
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func isConnNeedsRefreshError(code, message string) bool {
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if code == readOnlyTransactionCode || code == cannotConnectNowCode {
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return true
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}
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if code == featureNotSupportedCode && message == cannotSetReadWriteModeDuringRecoveryMsg {
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return true
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}
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return false
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}
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