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https://github.com/benweissmann/memongo
Easily run an in-memory MongoDB server for your Go unit tests
https://github.com/benweissmann/memongo
golang mocking mongo mongodb unit-testing
Last synced: 7 days ago
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Easily run an in-memory MongoDB server for your Go unit tests
- Host: GitHub
- URL: https://github.com/benweissmann/memongo
- Owner: benweissmann
- License: mit
- Created: 2019-06-20T03:37:53.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-04-11T17:00:58.000Z (6 months ago)
- Last Synced: 2024-09-18T02:59:06.177Z (16 days ago)
- Topics: golang, mocking, mongo, mongodb, unit-testing
- Language: Go
- Size: 60.5 KB
- Stars: 78
- Watchers: 3
- Forks: 13
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# memongo
[](https://github.com/benweissmann/memongo/actions?workflow=Go) [](https://godoc.org/github.com/benweissmann/memongo) [](https://goreportcard.com/report/github.com/benweissmann/memongo)
`memongo` is a Go package that spins up a real MongoDB server, backed by in-memory
storage, for use in testing and mocking during development. It's based on
[mongodb-memory-server](https://github.com/nodkz/mongodb-memory-server) for
NodeJS.
In general, it's better to mock out interaction with the database, so you don't
need to run a Mongo server during testing. But becuase most Mongo clients use
a fluent interface that's tough to mock, and sometimes you need to test the
queries themselves, it's often helpful to be able to spin up a Mongo server
quickly and easily. That's where `memongo` comes in!
# Project Status
Beta. Tests and CI are set up and working, but more esoteric configurations may not work. If Memongo isn't working on your platform, you might want to use `memongo.StartWithOptions()` and pass the correct download URL for your platform manually.
# Caveats and Notes
Currently, `memongo` only supports UNIX systems. CI will run on MacOS, Ubuntu Xenial, Ubuntu Trusty, and Ubuntu Precise. Other flavors of Linux may or may not work.
# Basic Usage
Spin up a server for a single test:
```go
func TestSomething(t *testing.T) {
mongoServer, err := memongo.Start("4.0.5")
if (err != nil) {
t.Fatal(err)
}
defer mongoServer.Stop()
connectAndDoStuff(mongoServer.URI(), memongo.RandomDatabase())
}
```
Spin up a server, shared between tests:
```go
var mongoServer memongo.Server;
func TestMain(m *testing.M) {
mongoServer, err = memongo.Start("4.0.5")
if (err != nil) {
log.Fatal(err)
}
defer mongoServer.Stop()
os.Exit(m.Run())
}
func TestSomething(t *testing.T) {
connectAndDoStuff(mongoServer.URI(), memongo.RandomDatabase())
}
```
# How it works
Behind the scenes, when you run `Start()`, a few things are happening:
1. If you specified a MongoDB version number (rather than a URL or binary path),
`memongo` detects your operating system and platform to determine the
download URL for the right MongoDB binary.
2. If you specified a MongoDB version number or download URL, `memongo`
downloads MongoDB to a cache location. For future runs, `memongo` will just
use the copy from the cache. You only need to be connected to the internet
the first time you run `Start()` for a particular MongoDB version.
3. `memongo` starts a process running the downloaded `mongod` binary. It uses
the `ephemeralForTest` storage engine, a temporary directory for a `dbpath`,
and a random free port number.
4. `memongo` also starts up a "watcher" process. This process is a simple
portable shell script that kills the `mongod` process when the current
process exits. This ensures that we don't leave behind `mongod` processes,
even if your tests exit uncleanly or you don't call `Stop()`.
# Configuration
The behavior of `memongo` can be controlled by using
`memongo.StartWithOptions` instead of `memongo.Start`. See
[the godoc](https://godoc.org/github.com/benweissmann/memongo) for all the options. Many options can also be set via environment variable.
A few common use-cases are covered here:
Note that you must use MongoDB version 3.2 or greater, because the `ephemeralForTest` storage engine was not present before 3.2.
## Set the cache path
`memongo` downloads a pre-compiled binary of MongoDB from https://www.mongodb.org and caches it on your local system. This path is set by (in order of preference):
- The `CachePath` passed to `memongo.StartWithOptions`
- The environment variable `MEMONGO_CACHE_PATH`
- If `XDG_CACHE_HOME` is set, `$XDG_CACHE_HOME/memongo`
- `~/.cache/memongo` on Linux, or `~/Library/Caches/memongo` on MacOS
## Override download URL
By default, `memongo` tries to detect the platform you're running on and download an official MongoDB release for it. If `memongo` doesn't yet support your platform, of you'd like to use a custom version of MongoDB, you can pass `DownloadURL` to `memongo.StartWithOptions` or set the environment variable `MEMONGO_DOWNLOAD_URL`.
`memongo`'s caching will still work with custom download URLs.
## Use a custom MongoDB binary
If you'd like to bypass `memongo`'s download beahvior entirely, you can pass `MongodBin` to `memongo.StartWithOptions`, or set the environment variable `MEMONGO_MONGOD_BIN` to the path to a `mongod` binary. `memongo` will use this binary instead of downloading one.
If you're running on a platform that doesn't have an official MongoDB release (such as Alpine), you'll need to use this option.
## Reduce or increase logging
By default, `memongo` logs at an "info" level. You may call `StartWithOptions` with `LogLevel: memongolog.LogLevelWarn` for fewer logs, `LogLevel: memongolog.LogLevelSilent` for no logs, or `LogLevel: memongolog.LogLevelDebug` for verbose logs (including full logs from MongoDB).
By default, `memongo` logs to stdout. To log somewhere else, specify a `Logger` in `StartWithOptions`.