Razorlight: Leaking Memory

[kspearrin]

I've been noticing that my web application is leaking memory somewhere. The leak is very slow, climbing about 1% every day on the server. In an effort try and find out what is causing these memory leaks I pulled dump files to compare about 4 days apart.

Comparing those two dump files shows the following:

All of these Microsoft.CodeAnalysis.CSharp.InternalSyntax.* instances add up to about 185mb of memory increase over those 4 days.

Viewing the instances of them looks like it is coming from my Razor mail templates.

Any idea why this is happening?

Here is my implementation of RazorLight for these templates:

• Initing RazorLightEngine
• Custom embedded resource ITemplateManager
• Engine parsing of mail templates

Is there something wrong with my implementation here or is there a bug somewhere in RazorLight? Thanks!

[kspearrin]

I created a simple load test to run 10,000 iterations of parsing embedded resource templates:

```c#
var engine = EngineFactory.CreateEmbedded(typeof(Program));

for(int i = 0; i < 10000; i++)
{
var model = new BaseMailModel
{
WebVaultUrl = "http://google.com",
SiteName = "Google"
};

var htmlContent = engine.Parse("Templates.Welcome", model);
var textContent = engine.Parse("Templates.Welcome.text", model);

}
```

Sample project for this test: RazorLightMemoryTests.zip

Diagnostic tools shows the same results as my productions dumps. There is definitely something leaking memory in here.

Look at all those GC.

[kspearrin]

The issue is not present in 2.0.0-alpha2. In fact, with 2.0.0 the loop of 10,000 compilations only takes < 1 second vs the 1.x example above taking nearly 60 seconds to get through just 2,000 iterations. Why the huge difference?

```c#
var factory = new EngineFactory();
var engine = factory.ForEmbeddedResources(typeof(Program));

for(int i = 0; i < 10000; i++)
{
var model = new BaseMailModel
{
WebVaultUrl = "http://google.com",
SiteName = "Google"
};

var htmlContent = await engine.CompileRenderAsync("Templates.Welcome", model);
var textContent = await engine.CompileRenderAsync("Templates.Welcome.text", model);

}
```

Here's the memory profile for a 1,000,000 iteration test which only took 60 seconds to complete:

[toddams]

[alexsandro-xpt]

I have same problem @kspearrin with RazorLight 1.1.0, I'm run it in Docker Container and the container ever down in 5 minutes after get his container memory limitation.

@toddams Are you told me in the 2.0.0-alpha2 it's not happen? I will try it right now.

[toddams]

Please, let me know about the results @alexsandro-xpt .

[alexsandro-xpt]

@toddams everything is fine right now 2.0.0-alpha2 there are no more memory leak.
I'm rendering 14 template per second for email sending, apparently it's alright right now.
Thank you!

[toddams]

Awesome :) I'm glad it works for you

[MFFoX]

Until .NET framework support is added back, us old timers are stuck with this memory leak. Do you have any rough ETA on the 2.0-beta2 release? Or is there something I can do to work around this?