KonfigMap 2.0.40

KonfigMap

KonfigMap is a .NET global tool that generates Kubernetes ConfigMap-compatible .properties files from ASP.NET Core JSON configuration files. It bridges ASP.NET Core's hierarchical JSON configuration and Kubernetes ConfigMaps / Kustomize configMapGenerator.

Installation

Install as a .NET Global Tool

dotnet tool install --global KonfigMap

Note: Requires .NET 10 SDK or later.

Verify Installation

konfigmap --version

Update

dotnet tool update --global KonfigMap

Uninstall

dotnet tool uninstall --global KonfigMap

Quick Start

# Simplest usage — point at your config file(s)
konfigmap -f appsettings.json

# Scan a directory
konfigmap -d ./config -o ./k8s/overlays/dev

# Multiple files with prefix
konfigmap -f appsettings.json -f appsettings.Production.json -p "DOTNET_"

Usage

konfigmap [options]

Options

Input / Output (required: at least one of -f or -d)

Option	Alias	Description	Default
--input-file	-f	One or more JSON config file paths to process
--input-dir	-d	One or more directories to scan recursively for JSON files
--output-dir	-o	Output directory for the generated file	.
--output-file	-O	Output filename	.env

Key Transformation

Option	Alias	Description	Default
--separator	-s	Replaces : and . in hierarchical keys (ASP.NET Core uses __ for env vars)	__
--prefix	-p	Prefix prepended to every key (e.g. DOTNET_, ASPNETCORE_)	(empty)

Filtering

Option	Alias	Description	Default
--exclude	-e	Regex — keys matching this are excluded	(empty)
--include	-i	Regex — only keys matching this are included	(empty)

Tokenization (for CI/CD)

Option	Alias	Description	Default
--tokenize	-t	Replace values with tokenized placeholders	false
--token-prefix		Opening delimiter for tokens	$(
--token-suffix		Closing delimiter for tokens	)

Output Control

Option	Description	Default
--leaf-only	Emit only leaf (terminal) values, skip section keys	true
--sort-keys	Sort output keys alphabetically	false
--dry-run	Print to stdout without writing a file	false

Examples

Basic: directory scan

konfigmap -d ./config -o ./k8s/overlays/dev

Multiple input files

konfigmap -f appsettings.json -f appsettings.Production.json -o ./k8s/overlays/prod

Prefix + custom separator

konfigmap -d ./config --prefix "DOTNET_" --separator "." -o ./output

Input (appsettings.json):

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=db;Database=myapp"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  }
}

Output (.env):

DOTNET_ConnectionStrings.DefaultConnection="Server=db;Database=myapp"
DOTNET_Logging.LogLevel.Default="Warning"

Tokenized output for CI/CD pipelines

konfigmap -f appsettings.json --tokenize --token-prefix "#{" --token-suffix "}#"

Output:

ConnectionStrings__DefaultConnection="#{ConnectionStrings__DefaultConnection}#"
Logging__LogLevel__Default="#{Logging__LogLevel__Default}#"

Filtering keys

# Exclude logging-related keys
konfigmap -f appsettings.json --exclude "Logging.*"

# Include only connection strings
konfigmap -f appsettings.json --include "ConnectionStrings.*"

Sorted + dry-run preview

konfigmap -d ./config --sort-keys --dry-run

Include parent keys

konfigmap -f appsettings.json --leaf-only false

Supported ASP.NET Core Configuration Patterns

KonfigMap handles all standard ASP.NET Core JSON configuration patterns, converting hierarchical JSON into flat key=value pairs using the : → __ (double underscore) convention that ASP.NET Core uses for environment variables.

Nested Objects

{ "Logging": { "LogLevel": { "Default": "Information" } } }

Logging__LogLevel__Default="Information"

Arrays (index-based keys)

{ "AllowedOrigins": [ "https://app.example.com", "https://admin.example.com" ] }

AllowedOrigins__0="https://app.example.com"
AllowedOrigins__1="https://admin.example.com"

Arrays of Objects

{
  "Endpoints": [
    { "Name": "Primary", "Url": "https://primary.example.com" },
    { "Name": "Secondary", "Url": "https://secondary.example.com" }
  ]
}

Endpoints__0__Name="Primary"
Endpoints__0__Url="https://primary.example.com"
Endpoints__1__Name="Secondary"
Endpoints__1__Url="https://secondary.example.com"

Dotted Namespace Keys (e.g. Microsoft.AspNetCore)

Dots in key names are normalized to the separator (default __):

{ "Logging": { "LogLevel": { "Microsoft.AspNetCore": "Warning" } } }

Logging__LogLevel__Microsoft__AspNetCore="Warning"

Scalar Types (booleans, integers, floats)

{ "MaxRetries": 3, "EnableFeature": true, "Ratio": 0.75 }

MaxRetries="3"
EnableFeature="True"
Ratio="0.75"

Complex Real-World Config (Serilog, Kestrel, etc.)

{
  "Serilog": {
    "WriteTo": [
      { "Name": "Console" },
      { "Name": "File", "Args": { "path": "/var/log/app.log" } }
    ]
  }
}

Serilog__WriteTo__0__Name=Console
Serilog__WriteTo__1__Name=File
Serilog__WriteTo__1__Args__path=/var/log/app.log

Special Characters in Keys

Character	Handling
: (colon)	Replaced with separator (__) — this is the standard hierarchy delimiter
. (dot)	Replaced with separator (__) — normalizes dotted namespace keys
- (dash)	Preserved as-is
_ (underscore)	Preserved as-is
Spaces	Preserved as-is

Using with Kubernetes Kustomize

KonfigMap output integrates directly with Kustomize's configMapGenerator:

Step 1: Generate the properties file:

konfigmap -f appsettings.Production.json -o ./k8s/overlays/prod

Step 2: Reference in kustomization.yaml:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - deployment.yaml

configMapGenerator:
  - name: myapp-config
    envs:
      - .env

Step 3: Use in your deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
        - name: myapp
          image: myapp:latest
          envFrom:
            - configMapRef:
                name: myapp-config

License

MIT