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Audit Trail Installation

Prerequisites​

  • .NET 8 or later
  • Entity Framework Core 8+ (for EF Core backend)
  • Sufficient storage space for audit records (plan for retention requirements)

Package Installation​

Core Audit Trail Package​

The core package provides the middleware and base abstractions:

dotnet add package Hermodr.AuditTrail

Storage Backend Packages​

Choose one or more storage backends based on your needs:

dotnet add package Hermodr.AuditTrail.NDJson

Entity Framework Core Backend (Database-Backed)​

dotnet add package Hermodr.AuditTrail.EntityFramework
dotnet add package Microsoft.EntityFrameworkCore.Sqlite

Replace Sqlite with your actual provider (SqlServer, Npgsql, PostgreSQL, etc.).

Package Overview​

PackagePurposeRequired
Hermodr.AuditTrailCore middleware and abstractions✅ Yes
Hermodr.AuditTrail.NDJsonNDJSON file-based backendFor file storage
Hermodr.AuditTrail.EntityFrameworkEF Core database backendFor database storage
Microsoft.EntityFrameworkCore.*Database providerFor EF Core backend

What's Included​

Core Package​

  • AuditTrailMiddleware — Middleware that records every published event
  • IAuditTrailWriter — Write interface for audit entries
  • IAuditTrailReader — Read interface for querying audit entries
  • AuditTrailEntry — Data contract for stored audit records

NDJSON Package​

  • NdJsonAuditTrail — NDJSON file-based implementation
  • AuditTrailStreamQuery — Stream-based query API
  • File rolling and retention management
  • IFileSystem abstraction for pluggable storage

EF Core Package​

  • AuditTrailDbContext — EF Core context with audit entities
  • DbAuditTrailEntry — Entity mapping
  • EntityAuditTrailRepository — Repository implementation
  • LINQ query support

Storage Requirements​

NDJSON Backend​

  • Disk space: Plan for ~1-10 MB per 10,000 events (depends on event size)
  • File retention: Default keeps 30 files, configurable
  • I/O: Sequential writes, concurrent reads supported

EF Core Backend​

  • Database: Requires relational database (SQL Server, PostgreSQL, SQLite, etc.)
  • Table size: Grows linearly with event count
  • Indexing: Recommended on EventType, Timestamp, Subject columns
  • Retention: Implement archival/deletion policy for compliance

Next Steps​

After installation:

  1. Concepts — Understand audit trail scope and use cases
  2. NDJSON Backend — Configure file-based storage
  3. Querying — Learn to read and filter audit entries
  4. Examples — See real-world usage patterns