README.md in slavery-2.0.0 vs README.md in slavery-2.1.0
- old
+ new
@@ -1,7 +1,9 @@
# Slavery - Simple, conservative slave reads for ActiveRecord
+[](https://travis-ci.org/kenn/slavery)
+
Slavery is a simple, easy to use gem for ActiveRecord that enables conservative slave reads, which means it doesn't automatically redirect all SELECTs to slaves.
Instead, you can do `Slavery.on_slave { User.count }` to send a particular query to a slave.
Background: Probably your app started off with one single database. As it grows, you would upgrade to a master-slave replication for redundancy. At this point, all queries still go to the master and slaves are just backups. With that configuration, it's tempting to run some long-running queries on the slave. And that's exactly what Slavery does.
@@ -47,10 +49,17 @@
development_slave:
<<: *common
```
+Optionally, you can use a database url for your connections:
+
+```yaml
+development: postgres://root:@localhost:5432/myapp_development
+development_slave: postgres://root:@localhost:5432/myapp_development_slave
+```
+
At this point, Slavery does nothing. Run tests and confirm that nothing is broken.
## Usage
To start using Slavery, you need to add `Slavery.on_slave` in your code. Queries in the `Slavery.on_slave` block run on the slave.
@@ -99,10 +108,16 @@
```ruby
Slavery.on_slave { User.create } # => ActiveRecord::StatementInvalid: Mysql2::Error: INSERT command denied...
```
+With Postgres you can set the entire database to be readonly:
+
+```SQL
+ALTER DATABASE myapp_development_slave SET default_transaction_read_only = true;
+```
+
It is a good idea to confirm this behavior in your test code as well.
## Disable temporarily
You can quickly disable slave reads by dropping the following line in `config/initializers/slavery.rb`.
@@ -137,6 +152,7 @@
Slavery.spec_key = "slave" #instead of production_slave
```
## Changelog
+* v2.1.0: Debug log support / Database URL support / Rails 3.2 & 4.0 compatibility (Thanks to [@citrus](https://github.com/citrus))
* v2.0.0: Rails 5 support