This library allows you to log events from Serilog directly to loki asynchronously without blocking the main thread of application execution (request in asp.net).
There is a full description of section that is needed in appsettings.json.
{
"Loki": {
"Disabled": false,
"AppName": "app-name",
"TenantId: "admin",
"Labels": {
"app": "app-name"
},
"PropertiesAsLabels": [
"level"
],
"SuppressProperties": [
"EventId",
"SourceContext",
"RequestId",
"RequestPath",
"ConnectionId"
],
"BatchPostingLimit": 50,
"ParallelismFactor": 2,
"UseInternalTimestamp": true,
"LeavePropertiesIntact": false,
"SkipReqResWithHeaders": {
"test-header": true
},
"EnableMetrics": true,
"Metrics": {
"LogsWriteFailCounterName": "logs_write_fail_counter",
"LogsWriteSuccessCounterName": "logs_write_success_counter",
"LogsSizeKbCounterName": "logs_size_kb_counter"
}
}
}
AppName(required) - your application name which lib write to logsLabels(required) - labels which provide to each log - key-valuePropertiesAsLabels(required) - labels which could be extracted from logEvent
{
"Loki": {
"AppName": "app-name",
"Labels": {
"app": "app-name"
},
"PropertiesAsLabels": [
"level"
]
}
}
TenantId(default = null) - header value forX-Scope-OrgIDwhich was added to typed LokiHttpClientSuppressProperties(default = false) - properties from logEvent which can be deleted before sending to lokiBatchPostingLimit(default = 20) - the size of the pack that will be sent to the loki in one requestParallelismFactor(default = 1) - how many parallel tasks will maintain logs queueUseInternalTimestamp(default = false) - iftrueuse internalTimestamp from logLeavePropertiesIntact(default = false) - iftruelogger remove not-labeled properties from logEvent, so formatter select only PropertiesAsLabelsSkipReqResWithHeaders(default = null) - list of headers which should be ignored during loggingDisabled(default = null) - if true, then turn off direct to loki logging
{
"Loki": {
"Disabled": false,
"TenantId: "admin",
"SuppressProperties": [
"EventId",
"SourceContext",
"RequestId",
"RequestPath",
"ConnectionId"
],
"BatchPostingLimit": 50,
"ParallelismFactor": 2,
"UseInternalTimestamp": true,
"LeavePropertiesIntact": false,
"SkipReqResWithHeaders": {
"test-header": true
}
}
}
If you need to enable metrics provide the additional section. You already need to add OpenTelemetry nuget packages and register services in Startup.cs.
EnableMetrics(default = false) - iftrueturn on metrics exportingMetrics- could be fulfilled ifEnableMetrics: trueLogsWriteFailCounterName(default = 'logs_write_fail_counter') - metric counter name for exporting (broken logs)LogsWriteSuccessCounterName(default = 'logs_write_success_counter') - metric counter name for exporting (correct logs)LogsSizeKbCounterName(default = 'logs_size_kb_counter') - metric counter name for exporting (correct logs size in kb)
{
"Loki": {
"EnableMetrics": true,
"Metrics": {
"MapPath": "/metrics",
"Port": 82,
"UseDefaultCollectors": false,
"LogsWriteFailCounterName": "logs_write_fail_counter",
"LogsWriteSuccessCounterName": "logs_write_success_counter",
"LogsSizeKbCounterName": "logs_size_kb_counter"
}
}
}
- Provide section in appsettings.json
{
"Loki": {
"AppName": "app-name",
"Labels": {
"app": "app-name"
},
"PropertiesAsLabels": [
"level"
]
}
}
- in Startup.ConfigureServices add line
services.AddDirectToLokiLogging(configuration, c =>
c.BaseAddress = new Uri("http://loki.net:3100"));
-
Optional (1): if it is needed to skip logs in your RequestResponseLoggingMiddleware useRequestResponseLoggingFilter(httpContext)method like an aid in determining which logs should be skipped. -
Optional (2)if you need to export logs metrics, you should add
services.AddOpenTelemetry()
.WithMetrics(builder => builder
.AddPrometheusExporter(...)
.AddDirectLokiLoggingMeter();
);
in startup.cs file.
Create new ASP.NET Core WebApplication.
In appsettings.json add section below
"Loki": {
"AppName": "example-app",
"BatchPostingLimit": 2,
"Labels": {
"app": "example-app"
},
"PropertiesAsLabels": [
"level"
],
"SuppressProperties": [
"EventId",
"SourceContext",
"RequestId",
"RequestPath",
"ConnectionId"
]
}
Your Program.cs should look like this
using System;
using Aerx.Serilog.Sinks.Loki.Extensions;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDirectToLokiLogging(builder.Configuration, c =>
{
c.BaseAddress = new Uri("http://localhost:3100");
c.Timeout = TimeSpan.FromSeconds(5);
});
var app = builder.Build();
app.Run();
Add new endpoint
app.MapPost("/test", async x =>
{
var logger = x.RequestServices.GetRequiredService<ILogger<Program>>();
logger.LogInformation("test log");
});
Then open grafana/loki explorer and search logs for label {app="example-app"}
There is a more advanced example in samples directory.
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