Logs are never pushed with docker-compose

[nhatmvo]

I'm using .NET 6
Serilog.Sinks.Grafana.Loki v8.0.1
I'm trying to implement Grafana Loki following with this article: https://medium.com/c-sharp-progarmming/net-core-microservice-logging-with-grafana-and-loki-92cd2783ed88
but it seems like the logs never push into loki. here's my code from Program.cs file:

var builder = WebApplication.CreateBuilder(args);

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Override("Microsoft", Serilog.Events.LogEventLevel.Warning)
    .Enrich.FromLogContext()
    .WriteTo.Console()
    .CreateLogger();

....
builder.Host.UseSerilog((ctx, cfg) =>
{
    cfg.Enrich.WithProperty("Application", ctx.HostingEnvironment.ApplicationName)
        .Enrich.WithProperty("Environment", ctx.HostingEnvironment.EnvironmentName)
        .WriteTo.Console(new RenderedCompactJsonFormatter())
        .WriteTo.GrafanaLoki(ctx.Configuration["loki"]);
});

....
app.UseSerilogRequestLogging();

docker-compose file is pretty much like the article above:

`version: '3.4'

services:
  lokigraf.api:
    image: ${DOCKER_REGISTRY-}dotnetgrafanalokiapi
    build:
      context: .
      dockerfile: dotnet.GrafanaLoki.API/Dockerfile
    environment:
        loki: http://loki:3100
        ASPNETCORE_ENVIRONMENT: Development
        ASPNETCORE_URLS: https://+:443;http://+:80
    ports:
        - 8085:80
        - 8086:443
    depends_on:
        loki:
            condition: service_healthy

  loki:
    container_name: loki
    image: grafana/loki:master
    ports:
       - 3100:3100
    command: -config.file=/etc/loki/local-config.yaml
    healthcheck:
        test: wget -q --tries=1 -O- http://localhost:3100/ready 
        interval: 3s
        timeout: 3s
        retries: 10
        start_period: 10s

  grafana:
    container_name: grafana
    image: grafana/grafana:master
    ports:
      - "3000:3000"
    depends_on:
        loki:
            condition: service_healthy`

it still works when using Serilog to log to the console (I've checked within container logs), and I've tried SelfLog but having no error neither. what am I missing here?

[nhatmvo]

EDIT: seems like there's a change from v8 that using the different logging format: https://github.com/serilog-contrib/serilog-sinks-grafana-loki/wiki/Using-LokiJsonTextFormatter-and-Grafana-Loki-json-parser
but how can I properly config Serilog to recognize the format it within my code above?

[mishamyte]

Hi @nhatmvo,

Did you have the opportunity to check out the sample from this app?

There are 2 samples: console app (configured by code) and web app (configured from config files) what works fine with Loki.
Also in this repo you could also find a docker-compose config for launching loki + grafana in compose.

Could this example of config and app be useful for you?

[mishamyte]

Guy from example reads Loki url from the config key, called loki and pass it as 1st param to sink.

BTW, I don't recommend to configure logger like that.
It would be more profitable to have full configuration in your appsetting.*.json and in code just configure logger with this configuration, as it is done in the example, referenced above

[nhatmvo]

yes, his idea is to manage the configuration within the code itself, I don't like his method as much. I've tried to downgrade the version for Loki Sink and it works fine

[nhatmvo]

@mishamyte thank you so much, I will try to reference with the sample code you mention and let you know if that work or not 🥇

[nhatmvo]

thanks to @mishamyte, it turns out to be I have to labeling the log to be written inside (either using LokiLabel or propertiesAsLabels if I had properties added previously) - that was the featured added within v8 that I have to explicitly specify which label to be added