mirror of https://github.com/k3s-io/k3s
92 lines
3.0 KiB
Markdown
92 lines
3.0 KiB
Markdown
go-dqlite [](https://travis-ci.org/canonical/go-dqlite) [](https://coveralls.io/github/canonical/go-dqlite?branch=master) [](https://goreportcard.com/report/github.com/canonical/go-dqlite) [](https://godoc.org/github.com/canonical/go-dqlite)
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======
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This repository provides the `go-dqlite` Go package, containing bindings for the
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[dqlite](https://github.com/canonical/dqlite) C library and a pure-Go
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client for the dqlite wire [protocol](https://github.com/canonical/dqlite/blob/master/doc/protocol.md).
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Usage
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-----
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The best way to understand how to use the ```go-dqlite``` package is probably by
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looking at the source code of the [demo
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program](https://github.com/canonical/go-dqlite/tree/master/cmd/dqlite-demo) and
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use it as example.
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Build
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-----
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In order to use the go-dqlite package in your application, you'll need to have
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the [dqlite](https://github.com/canonical/dqlite) C library installed on your
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system, along with its dependencies. You then need to pass the ```-tags```
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argument to the Go tools when building or testing your packages, for example:
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```bash
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go build -tags libsqlite3
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go test -tags libsqlite3
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```
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Documentation
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-------------
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The documentation for this package can be found on [Godoc](http://godoc.org/github.com/canonical/go-dqlite).
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Demo
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----
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To see dqlite in action, either install the Debian package from the PPA:
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```bash
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sudo add-apt-repository -y ppa:dqlite/stable
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sudo apt install dqlite libdqlite-dev
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```
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or build the dqlite C library and its dependencies from source, as described
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[here](https://github.com/canonical/dqlite#build), and then run:
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```
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go install -tags libsqlite3 ./cmd/dqlite-demo
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```
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from the top-level directory of this repository.
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Once the ```dqlite-demo``` binary is installed, start three nodes of the demo
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application, respectively with IDs ```1```, ```2,``` and ```3```:
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```bash
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dqlite-demo start 1 &
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dqlite-demo start 2 &
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dqlite-demo start 3 &
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```
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The node with ID ```1``` automatically becomes the leader of a single node
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cluster, while the nodes with IDs ```2``` and ```3``` are waiting to be notified
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what cluster they belong to. Let's make nodes ```2``` and ```3``` join the
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cluster:
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```bash
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dqlite-demo add 2
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dqlite-demo add 3
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```
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Now we can start using the cluster. The demo application is just a simple
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key/value store that stores data in a SQLite table. Let's insert a key pair:
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```bash
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dqlite-demo update my-key my-value
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```
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and then retrive it from the database:
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```bash
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dqlite-demo query my-key
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```
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Currently node ```1``` is the leader. If we stop it and then try to query the
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key again we'll notice that the ```query``` command hangs for a bit waiting for
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the failover to occur and for another node to step up as leader:
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```
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kill -TERM %1; sleep 0.1; dqlite-demo query my-key; dqlite-demo cluster
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```
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