🚀 HelmEnvDelta

GitOps-safe YAML sync for Helm values across environments (Dev → UAT → Prod)

Sync YAML configs across environments in seconds, not hours.

🛡️ Stop production incidents from configuration drift—before they happen.

HelmEnvDelta (hed) automates environment synchronization for GitOps workflows while protecting your production-specific settings and preventing dangerous changes.

👤 Who Is This For?

Platform/SRE teams owning multiple environment repos
Teams with repeated UAT → Prod copy-paste workflows
Helm/GitOps users burned by config drift and sync errors

Not a Helm plugin · Not a live cluster diff · Not a general YAML linter

HelmEnvDelta syncs files, not running clusters. Use alongside Helm, ArgoCD, or Flux—not instead of them.

💡 Why Teams Love HelmEnvDelta

Problem	Impact	HelmEnvDelta Outcome
Copying UAT → Prod by hand	30+ minutes, human errors	1 min scripted sync for 50+ files
Hidden config drift	Incidents in Prod	Stop rules & fixed values prevent unsafe changes
Accidental overwrites	Production namespaces, replicas corrupted	`skipPath` preserves env-specific values
Major version slips	Breaking changes in Prod	`semverMajorUpgrade` rule blocks v1→v2
Inconsistent YAML formatting	Noisy git diffs, painful reviews	Standardized formatting, clean diffs

✨ Key Features

🔍 Smart YAML Diff - Compares structure, not text. Ignores formatting, comments, and array reordering to show only meaningful changes.

🎯 Path Filtering - Preserve environment-specific values (namespaces, replicas, secrets) that should never sync.

📌 Fixed Values - Set specific fields to constant values regardless of source/destination. Enforce production settings like debug: false or replicas: 3 after every sync.

🔄 Powerful Transforms - Regex find/replace for both file content and paths. Load transforms from external YAML files for reusability. Change uat-db.internal → prod-db.internal automatically.

🛡️ Safety Rules - Block major version upgrades, scaling violations, and forbidden patterns. Load validation rules from external files. Scan globally or target specific fields.

🎨 Format Enforcement - Standardize YAML across all environments: key ordering, indentation, quoting, array sorting.

📦 Config Inheritance - Reuse base configurations with environment-specific overrides.

📊 Multiple Reports - Console, HTML (visual), and JSON (CI/CD) output formats.

🔍 Discovery Tools - Preview files (-l), inspect config (--show-config), filter by filename/content (-f), filter by change type (-m), validate with comprehensive warnings including unused pattern detection.

💡 Smart Suggestions - Heuristic analysis (--suggest) detects patterns and recommends transforms and stop rules automatically. Control sensitivity with --suggest-threshold.

🛡️ Safety First - Pre-execution summary, first-run tips, improved error messages with helpful examples.

⚡ High Performance - 45-60% faster than alternatives with intelligent caching and parallel processing.

🔔 Auto Updates - Notifies when newer versions are available (skips in CI/CD).

📥 Installation

npm install -g helm-env-delta

Requirements: Node.js ≥ 22, npm ≥ 9

🎯 Quick Start

1️⃣ Create Config

# config.yaml
source: './uat'
destination: './prod'

skipPath:
  '**/*.yaml':
    - 'metadata.namespace' # Never overwrite prod namespace
    - 'spec.replicas' # Keep prod scaling

transforms:
  '**/*.yaml':
    content:
      - find: "-uat\\b"
        replace: '-prod'

2️⃣ Preview Changes

hed -c config.yaml -D -d

3️⃣ Execute Sync

hed -c config.yaml

4️⃣ Review in Browser

hed -c config.yaml -H

5️⃣ Get Smart Suggestions (Optional)

hed -c config.yaml --suggest

# Control suggestion sensitivity (0-1, default: 0.3)
hed -c config.yaml --suggest --suggest-threshold 0.7

Analyzes differences and suggests transforms and stop rules automatically with configurable confidence filtering.

Done! All files synced, production values preserved, changes validated.

🎬 Real-World Use Cases

🏢 Multi-Service GitOps

Challenge: 20+ microservices across Dev → UAT → Prod. Each has environment-specific namespaces, resource limits, and URLs.

A platform team managing 25 microservices across 3 environments used to spend 2 hours every release copying and tweaking values files. Now 2 engineers sync everything in under 5 minutes with zero manual edits.

Solution:

source: './helm/uat'
destination: './helm/prod'

skipPath:
  '**/*.yaml':
    - 'metadata.namespace'
    - 'resources.limits'
    - 'spec.replicas'

transforms:
  '**/*.yaml':
    content:
      - find: '-uat\\b'
        replace: '-prod'

Result: Sync 50+ files in 5 seconds with zero risk of overwriting production settings.

🚨 Prevent Production Incidents

Challenge: Production incidents from accidental major version upgrades or scaling beyond cluster capacity.

After a v1→v2 image upgrade slipped through and caused a 4-hour outage, the team added semverMajorUpgrade rules. They've blocked 12 accidental major bumps since—and zero incidents.

Solution:

stopRules:
  'services/**/values.yaml':
    - type: 'semverMajorUpgrade' # Block v1.x → v2.x
      path: 'image.tag'
    - type: 'numeric' # Enforce limits
      path: 'replicaCount'
      min: 2
      max: 10

Result: Dangerous changes blocked automatically. Use --force only when you intend it.

📐 Standardize Formatting

Challenge: Different editors, different formatting. Git diffs full of noise.

Code reviews were painful: 80% of diff lines were formatting noise. After enabling outputFormat, PRs became clean structural diffs that reviewers actually read.

Solution:

outputFormat:
  indent: 2
  keySeparator: true
  keyOrders:
    '**/*.yaml':
      - 'apiVersion'
      - 'kind'
      - 'metadata'
      - 'spec'
  arraySort:
    '**/*.yaml':
      - path: 'env'
        sortBy: 'name'
        order: 'asc'

Result: Every file formatted consistently. Clean diffs. Easier reviews.

🎓 Live Examples

The repository includes ready-to-run examples:

📁 Example 1: Config Inheritance

Shows how to reuse base configuration across multiple environment pairs.

helm-env-delta --config example/1-config-inheritance/config.uat-to-prod.yaml --dry-run --diff

🚦 Example 2: Stop Rules

Demonstrates all 5 stop rule types and how violations block execution.

helm-env-delta --config example/2-stop-rules/config.yaml --dry-run --diff

⛓️ Example 3: Multi-Environment Chain

Progressive promotion through Dev → UAT → Prod with cumulative transforms.

cd example/3-multi-env-chain
./sync-all.sh

🗑️ Example 4: Prune Mode

File deletion behavior with prune: true vs prune: false.

helm-env-delta --config example/4-prune-mode/config.with-prune.yaml --dry-run --diff

📦 Example 5: External Files

Load transforms and stop rules from external YAML files for better organization and reusability.

helm-env-delta --config example/5-external-files/config.yaml --dry-run --diff

Features shown:

Transform files (contentFile, filenameFile)
Pattern files (regexFile, regexFileKey)
Global vs targeted regex validation

📌 Example 6: Fixed Values

Set specific fields to constant values regardless of source/destination. Perfect for enforcing production settings.

helm-env-delta --config example/6-fixed-values/config.yaml --dry-run --diff

Features shown:

Simple path fixed values (debug: false, logLevel: warn)
Nested paths (spec.replicas)
Array filter operators (env[name=LOG_LEVEL].value)
Combining with skipPath and transforms

🎨 Example 7: Format-Only Mode

Format YAML files without syncing. No source directory required - perfect for standardizing existing files.

# Preview which files would be formatted
helm-env-delta --config example/7-format-only/config.yaml --format-only --list-files

# Preview formatting changes
helm-env-delta --config example/7-format-only/config.yaml --format-only --dry-run

# Apply formatting
helm-env-delta --config example/7-format-only/config.yaml --format-only

Features shown:

Format-only mode (no source required)
Combining --format-only with --list-files to preview files
Key ordering, array sorting, indentation standardization
Minimal config for formatting existing files

💡 Smart Configuration Suggestions (Heuristic)

The --suggest flag uses heuristic analysis to examine differences between environments and automatically recommend configuration updates. This intelligent pattern detection helps bootstrap your config by discovering repeated changes and potential safety rules.

How It Works

helm-env-delta --config config.yaml --suggest

# Control suggestion sensitivity (higher threshold = fewer, higher-confidence suggestions)
helm-env-delta --config config.yaml --suggest --suggest-threshold 0.7

How heuristic analysis works:

🔍 Intelligently detects repeated value changes across files
🎯 Suggests transform patterns (regex find/replace) based on semantic patterns
🛡️ Recommends stop rules for safety validation using pattern recognition
📊 Provides confidence scores and occurrence counts for each suggestion
🎛️ NEW: Configurable threshold filters suggestions by confidence level (0-1)
📝 Outputs copy-paste ready YAML configuration
✨ Enhanced noise filtering:
- Ignores UUIDs, timestamps, single-character changes
- Filters antonym pairs (enable/disable, true/false, on/off)
- Filters regex special characters (unless semantic keywords present)
- Filters version-number-only changes (service-v1 → service-v2)
- Allows semantic patterns even with special chars (db.uat.com → db.prod.com)

Example Output

# Suggested Transforms
transforms:
  '**/*.yaml':
    content:
      - find: 'uat-cluster'
        replace: 'prod-cluster'
        # Confidence: 95% (42 occurrences across 12 files)

# Suggested Stop Rules
stopRules:
  '**/*.yaml':
    - type: 'semverMajorUpgrade'
      path: 'image.tag'
      # Detected version changes: v1.2.3 → v2.0.0

When to Use

🚀 First-time setup: Let heuristics discover patterns automatically instead of manual analysis
🔄 Config refinement: Find missing transforms or stop rules through smart detection
📚 Learning tool: Understand what's changing between environments
⚡ Quick start: Bootstrap configuration from existing files using intelligent pattern matching
🧠 Pattern discovery: Leverage heuristic algorithms to identify semantic transformations (uat→prod, staging→production)
🎯 Confidence tuning: Adjust threshold to balance between finding all patterns vs. high-confidence only

Confidence threshold control:

# More suggestions (lower threshold = less strict)
helm-env-delta --config config.yaml --suggest --suggest-threshold 0.2

# Default balance (standard heuristics, threshold: 0.3)
helm-env-delta --config config.yaml --suggest

# Only high-confidence (higher threshold = more strict)
helm-env-delta --config config.yaml --suggest --suggest-threshold 0.8

Workflow:

# 1. Get suggestions (optionally with custom threshold)
helm-env-delta --config config.yaml --suggest --suggest-threshold 0.5 > suggestions.yaml

# 2. Review and copy relevant sections to config.yaml

# 3. Test with dry-run
helm-env-delta --config config.yaml --dry-run --diff

# 4. Execute
helm-env-delta --config config.yaml

⚙️ Configuration Reference

🎯 Core Settings

source: './uat' # Required: Source folder (optional with --format-only)
destination: './prod' # Required: Destination folder (must differ from source)

include: # Optional: File patterns (default: all)
  - '**/*.yaml'
exclude: # Optional: Exclude patterns
  - '**/test*.yaml'

prune: false # Optional: Delete dest files not in source
confirmationDelay: 3000 # Optional: Delay in ms before sync (default: 3000, 0 to disable)

Note: Source and destination paths cannot resolve to the same folder.

🔒 Path Filtering (skipPath)

Preserve environment-specific fields during sync.

skipPath:
  'apps/*.yaml':
    - 'metadata.namespace' # Top-level field
    - 'spec.destination.namespace' # Nested field
    - 'spec.ignoreDifferences[*].jsonPointers' # Array wildcard

  'services/**/values.yaml':
    - 'microservice.env[*].value' # All array items
    - 'resources.limits'

Filter Expressions (Skip by Name)

Skip specific array items by property value using CSS-style filter operators:

Operator	Name	Example	Matches
`=`	equals	`[name=DEBUG]`	Exact match
`^=`	startsWith	`[name^=DB_]`	`DB_HOST`, `DB_PORT`
`$=`	endsWith	`[name$=_KEY]`	`API_KEY`, `SECRET_KEY`
`*=`	contains	`[name*=SECRET]`	`MY_SECRET_KEY`, `SECRET`

skipPath:
  '**/*.yaml':
    # Equals (=) - exact match
    - 'env[name=SECRET_KEY]' # Skip item where name=SECRET_KEY
    - 'containers[name=sidecar]' # Skip entire sidecar container

    # StartsWith (^=) - prefix match
    - 'env[name^=DB_]' # Skip DB_HOST, DB_PORT, DB_USER
    - 'containers[name^=init-]' # Skip init-db, init-cache

    # EndsWith ($=) - suffix match
    - 'env[name$=_SECRET]' # Skip API_SECRET, DB_SECRET
    - 'volumes[name$=-data]' # Skip app-data, cache-data

    # Contains (*=) - substring match
    - 'env[name*=PASSWORD]' # Skip DB_PASSWORD, PASSWORD_HASH
    - 'containers[image*=nginx]' # Skip any nginx image

    # Nested paths with mixed operators
    - 'spec.containers[name^=sidecar-].env[name$=_KEY]'

Syntax:

array[prop=value] - Match items where property equals value
array[prop^=prefix] - Match items where property starts with prefix
array[prop$=suffix] - Match items where property ends with suffix
array[prop*=substring] - Match items where property contains substring
array[prop="value with spaces"] - Quoted values for special characters
Combine with wildcards: containers[name=app].env[*].value

Use cases: Namespaces, replicas, resource limits, secrets, URLs, environment-specific array items, batch filtering by naming conventions.

📌 Fixed Values (fixedValues)

Set specific JSONPath locations to constant values, regardless of source/destination values. Applied after merge, before formatting.

fixedValues:
  # Apply to all YAML files
  '**/*.yaml':
    - path: 'debug'
      value: false
    - path: 'logLevel'
      value: 'warn'

  # Specific file patterns
  'deployment.yaml':
    - path: 'spec.replicas'
      value: 3
    - path: 'spec.template.spec.containers[name=app].resources.limits.memory'
      value: '512Mi'

  # Array filter operators supported
  'configmap.yaml':
    - path: 'data.env[name=LOG_LEVEL].value'
      value: 'info'
    - path: 'data.env[name^=FEATURE_].value' # startsWith
      value: 'stable'

Supported filter operators: = (equals), ^= (startsWith), $= (endsWith), *= (contains) - updates ALL matching items

Value types: String, number, boolean, null, object, array

Behavior:

Filter operators update ALL matching items (e.g., env[name^=LOG_] updates every item starting with LOG_)
Applied during diff computation, so changes are visible in all reports (HTML, console, JSON)
Non-existent paths are silently skipped
Multiple rules for same path: last one wins
Works with skipPath (fixedValues applied after skipPath restoration)

Use cases: Enforce production settings (debug: false), standardize resource limits, set mandatory environment variables, ensure consistent configuration across syncs.

🔄 Transformations

Regex find/replace for content and file paths. Load transforms from external files or define inline.

Inline Transforms (Regex)

transforms:
  'services/**/values.yaml':
    content: # Transform YAML values (not keys)
      - find: "uat-db\\.(.+)\\.internal"
        replace: 'prod-db.$1.internal' # Capture group $1

  'config/**/*.yaml':
    filename: # Transform file paths
      - find: 'envs/uat/'
        replace: 'envs/prod/'
      - find: '-uat\.'
        replace: '-prod.'

File-Based Transforms (Literal)

Load transforms from external YAML files for better organization and reusability:

transforms:
  '**/*.yaml':
    # Load content transforms from files (literal string replacement)
    contentFile:
      - './transforms/common.yaml' # Single file
      - './transforms/services.yaml' # Or array of files

    # Load filename transforms from file
    filenameFile: './transforms/paths.yaml'

    # Can combine with inline transforms (file-based run first)
    content:
      - find: 'v(\d+)-uat'
        replace: 'v$1-prod'

Transform file format (key:value pairs):

# transforms/common.yaml - literal string replacements
staging: production
stg: prod
staging-db.internal: production-db.internal

Execution order:

File-based transforms (literal, case-sensitive)
Inline regex transforms (patterns)

Content scope: All string values in matched files Filename scope: Full relative path (folders + filename) Processing: Sequential (rule 1 output → rule 2 input)

🛡️ Stop Rules

Block dangerous changes before deployment.

Icon	Rule Type	Purpose	Example
🚫	`semverMajorUpgrade`	Block major version bumps	Prevent `v1.2.3` → `v2.0.0`
⬇️	`semverDowngrade`	Block any downgrades	Prevent `v1.3.0` → `v1.2.0`
📏	`versionFormat`	Enforce strict format	Reject `1.2`, `v1.2.3-rc`, require `1.2.3`
🔢	`numeric`	Validate ranges	Keep `replicas` between 2-10
🔤	`regex`	Block patterns (inline)	Reject `v0.x` pre-release versions
📄	`regexFile`	Block patterns (from file)	Load forbidden patterns from YAML array
🔑	`regexFileKey`	Block transform file keys	Use transform keys as forbidden patterns

Inline Stop Rules

stopRules:
  'services/**/values.yaml':
    - type: 'semverMajorUpgrade'
      path: 'image.tag'

    - type: 'numeric'
      path: 'replicaCount'
      min: 2
      max: 10

    - type: 'versionFormat'
      path: 'image.tag'
      vPrefix: 'required' # or 'forbidden', 'allowed'

    # Regex with path (targeted)
    - type: 'regex'
      path: 'image.tag'
      regex: '^v0\.'

    # NEW: Regex without path (global - scans all values)
    - type: 'regex'
      regex: '^127\.' # Block localhost IPs anywhere

File-Based Stop Rules

Load validation patterns from external files:

stopRules:
  '**/*.yaml':
    # Load patterns from array file (with path - targeted)
    - type: 'regexFile'
      path: 'image.tag'
      file: './patterns/forbidden-versions.yaml'

    # Load patterns from array file (without path - global scan)
    - type: 'regexFile'
      file: './patterns/forbidden-global.yaml'

    # Use transform file keys as patterns (targeted)
    - type: 'regexFileKey'
      path: 'service.name'
      file: './transforms/common.yaml'

Pattern file format (array):

# patterns/forbidden-versions.yaml
- ^0\..* # Block 0.x.x versions
- .*-alpha.* # Block alpha releases
- .*-beta.* # Block beta releases

Path modes:

With path: Check specific field only (targeted)
Without path: Scan all values recursively (global)

Override: Use --force to bypass stop rules when needed.

🎨 Output Formatting

Standardize YAML across all environments.

outputFormat:
  indent: 2 # Indentation size
  keySeparator: true # Blank line between top-level keys (or second-level keys when single top-level key)

  keyOrders: # Custom key ordering
    'apps/*.yaml':
      - 'apiVersion'
      - 'kind'
      - 'metadata'
      - 'spec'

  arraySort: # Sort arrays
    'services/**/values.yaml':
      - path: 'env'
        sortBy: 'name'
        order: 'asc'

  quoteValues: # Force quoting
    'services/**/values.yaml':
      - 'env[*].value'

Benefits: Consistent formatting, cleaner diffs, better readability.

🔗 Config Inheritance

Reuse base configurations across environment pairs.

Base config (base.yaml):

include: ['**/*.yaml']
prune: true

skipPath:
  'apps/*.yaml':
    - 'spec.destination.namespace'

outputFormat:
  indent: 2
  keySeparator: true

Environment config (prod.yaml):

extends: './base.yaml' # Inherit base settings

source: './uat'
destination: './prod'

transforms: # Add environment-specific transforms
  '**/*.yaml':
    content:
      - find: '-uat\\b'
        replace: '-prod'

stopRules: # Add production safety rules
  'services/**/values.yaml':
    - type: 'semverMajorUpgrade'
      path: 'image.tag'

Merging:

Primitives (source, destination, prune, confirmationDelay): Child overrides parent
Arrays (include, exclude): Concatenated (parent + child)
Per-file Records (skipPath, transforms, stopRules, fixedValues): Keys merged, arrays concatenated
outputFormat: Shallow merged (child fields override parent)
Max depth: 5 levels

🖥️ CLI Reference

Commands

helm-env-delta --config <file> [options]
hed --config <file> [options]  # Short alias

Options

Flag	Short	Description
`--config <path>`	`-c`	Required - Configuration file
`--validate`		Validate config and pattern usage (shows warnings)
`--suggest`		Analyze differences and suggest config updates
`--suggest-threshold <0-1>`		Minimum confidence for suggestions (default: 0.3)
`--dry-run`	`-D`	Preview changes without writing files
`--force`		Override stop rules
`--diff`	`-d`	Show console diff
`--diff-html`	`-H`	Generate HTML report (opens in browser)
`--diff-json`	`-J`	Output JSON to stdout (pipe to jq)
`--list-files`	`-l`	List files without processing (takes precedence over --format-only)
`--show-config`		Display resolved config after inheritance
`--format-only`		Format destination files only (source not required)
`--skip-format`	`-S`	Skip YAML formatting during sync
`--filter <string>`	`-f`	Filter files by filename or content (case-insensitive)
`--mode <type>`	`-m`	Filter by change type: new, modified, deleted, all (default: all)
`--no-color`		Disable colored output (CI/accessibility)
`--verbose`		Show detailed debug info
`--quiet`		Suppress output except errors

Examples

# Validate configuration (shows warnings)
hed -c config.yaml --validate

# Get smart configuration suggestions
hed -c config.yaml --suggest

# Get only high-confidence suggestions
hed -c config.yaml --suggest --suggest-threshold 0.7

# Preview files that will be synced
hed -c config.yaml -l

# Display resolved config (after inheritance)
hed -c config.yaml --show-config

# Preview with diff
hed -c config.yaml -D -d

# Visual HTML report
hed -c config.yaml -H

# CI/CD integration (no colors)
hed -c config.yaml -J --no-color | jq '.summary'

# Execute sync
hed -c config.yaml

# Force override stop rules
hed -c config.yaml --force

# Filter to only process files matching 'prod'
hed -c config.yaml -f prod -d

# Sync only new files
hed -c config.yaml -m new

# Preview modified files only
hed -c config.yaml -m modified -D -d

# Combine filter and mode
hed -c config.yaml -f deployment -m modified -D -d

# Format destination files only (no sync, source not required in config)
hed -c config.yaml --format-only

# Preview format changes
hed -c config.yaml --format-only -D

# List files that would be formatted (--list-files takes precedence)
hed -c config.yaml --format-only -l

# Format-only config example (no source needed):
# destination: './prod'
# outputFormat:
#   indent: 2

🔄 Typical Workflow

flowchart LR
    A[💾 UAT Files] --> B[⚙️ Config]
    B --> C[🔍 Preview]
    C --> D{✅ Approve?}
    D -->|Yes| E[🚀 Execute]
    D -->|No| F[📝 Adjust]
    F --> C
    E --> G[📁 Prod Updated]
    G --> H[🔄 Git Commit]
    H --> I[🚢 Deploy]

Step-by-step:

# 1. Preview changes
hed -c config.yaml -D -d

# 2. Review in browser
hed -c config.yaml -H

# 3. Execute sync
hed -c config.yaml

# 4. Git workflow
git add prod/
git commit -m "Sync UAT to Prod"
git push origin main

🏆 Why Choose HelmEnvDelta?

🆚 Compared to Alternatives

HelmEnvDelta is purpose-built for environment synchronization, not template generation or deployment.

What You Get	vs Helmfile	vs Kustomize	vs Bash Scripts
🔍 Structural YAML diff	✅ Yes	❌ No	❌ No
🎯 Environment-aware sync	✅ Yes	⚠️ Manual	⚠️ Custom
🛡️ Safety validation	✅ Built-in	❌ None	⚠️ DIY
🔄 Smart merge	✅ Deep merge	⚠️ Limited	⚠️ DIY
🎨 Format enforcement	✅ Yes	❌ No	❌ No
📚 Learning curve	🟢 Low	🟡 Medium	🔴 High

Complementary: Use HelmEnvDelta alongside Helm, Helmfile, Kustomize, ArgoCD, or Flux.

💪 Benefits

✅ Safety - Stop rules prevent dangerous changes. Dry-run previews everything.

✅ Speed - 30 minutes → 1 minute sync time. Parallel processing.

✅ Consistency - Uniform YAML formatting. No more diff noise.

✅ Auditability - Field-level change tracking with JSONPath. Clean structural diffs.

✅ Flexibility - Per-file patterns. Config inheritance. Regex transforms.

✅ Reliability - 1150+ tests, 84% coverage. Battle-tested.

📊 JSON Output for CI/CD

hed --config config.yaml --diff-json > report.json

Schema:

{
  "metadata": {
    "timestamp": "2025-12-27T10:30:00Z",
    "source": "./uat",
    "destination": "./prod",
    "dryRun": true
  },
  "summary": {
    "added": 2,
    "changed": 3,
    "deleted": 1,
    "unchanged": 15
  },
  "files": {
    "changed": [
      {
        "path": "prod/app.yaml",
        "changes": [
          {
            "path": "$.image.tag",
            "oldValue": "v1.2.3",
            "updatedValue": "v1.3.0"
          }
        ]
      }
    ]
  },
  "stopRuleViolations": [
    {
      "file": "prod/app.yaml",
      "rule": { "type": "semverMajorUpgrade" },
      "message": "Major upgrade: v1.2.3 → v2.0.0"
    }
  ]
}

Use with jq:

# Summary
jq '.summary' report.json

# Violations
jq '.stopRuleViolations' report.json

# Changed files
jq '.files.changed[].path' report.json

🔧 Advanced Features

🧠 Structural Comparison

Git diffs are noisy when arrays are reordered. HelmEnvDelta compares YAML structure and recognizes identical content regardless of order.

Example:

# Source
env:
  - name: DB_URL
    value: uat-db
  - name: LOG_LEVEL
    value: debug

# Destination
env:
  - name: LOG_LEVEL
    value: info
  - name: DB_URL
    value: prod-db

Git diff: Shows all lines changed (noisy) HelmEnvDelta: Only LOG_LEVEL: debug → info (clean)

🔍 Pattern Usage Validation

HelmEnvDelta validates that your configuration patterns actually match files and exist in your YAML structure. This helps catch typos, outdated patterns, and misconfigured rules early.

Run validation:

helm-env-delta --config config.yaml --validate

What gets validated:

exclude patterns - Warns if pattern matches no files
skipPath patterns - Two-level validation:
- Glob pattern must match at least one file
- JSONPath must exist in at least one matched file
- Filter expressions [prop=value] validated against actual array items
stopRules patterns - Two-level validation:
- Glob pattern must match at least one file
- JSONPath (if specified) must exist in at least one matched file

Example output:

✓ Configuration is valid

⚠️  Pattern Usage Warnings (non-fatal):

  • Exclude pattern 'test/**/*.yaml' matches no files
  • skipPath pattern 'legacy/*.yaml' matches no files
  • skipPath JSONPath 'microservice.replicaCountX' not found in any matched files (Pattern: svc/**/values.yaml, matches 50 file(s))
  • stopRules glob pattern 'helm-charts/**/*.yaml' matches no files (3 rule(s) defined)
  • stopRules JSONPath 'spec.replicas' not found in any matched files (Rule type: numeric, matches 5 file(s))

Validation phases:

Phase 1 (Static): Validates config syntax, checks for inefficient patterns, duplicates, conflicts
Phase 2 (File-Based): Loads files and validates all patterns actually match and paths exist

When to use:

After updating configuration
When patterns stop working as expected
To verify config file patterns after file reorganization
As part of CI/CD pre-flight checks

Important: Warnings are non-fatal and don't block execution. They help you catch potential issues but won't stop your workflow.

🔀 Deep Merge

Preserves destination values for skipped paths.

# Source (UAT)
metadata:
  namespace: uat
spec:
  replicas: 3

# Config
skipPath:
  "*.yaml":
    - "metadata.namespace"
    - "spec.replicas"

# Destination (Prod) - preserved after sync!
metadata:
  namespace: prod  # ← Kept
spec:
  replicas: 5      # ← Kept

🆘 Common Issues

❓ Source and destination folders cannot be the same

Error: Source and destination folders cannot be the same

Fix: Ensure source and destination paths resolve to different directories. Paths like ./envs/../envs/prod and ./envs/prod will be detected as identical.

❓ Stop rule violations blocking sync

Error: 🛑 Stop Rule Violation (semverMajorUpgrade)

Fix: Review change carefully. Use --force if intentional.

❓ Transforms not applying

Check:

File pattern: **/*.yaml vs *.yaml
Regex escaping: \\. for literal dots
Word boundaries: \\b

❓ JSONPath syntax errors

# ❌ Wrong
- '$.spec.replicas' # Don't use $. prefix
- 'env.*.name' # Use [*] not .*

# ✅ Correct
- 'spec.replicas' # No prefix
- 'env[*].name' # Array wildcard
- 'env[name=DEBUG]' # Filter by exact value
- 'env[name^=DB_]' # Filter by prefix (startsWith)
- 'env[name$=_KEY]' # Filter by suffix (endsWith)
- 'env[name*=SECRET]' # Filter by substring (contains)
- 'containers[name=app].env[name=SECRET]' # Nested filters

❓ Glob patterns not matching

Pattern	Matches
`*.yaml`	Current directory only
`*/.yaml`	Recursive (all subdirs)
`apps/*.yaml`	One level deep
`apps/*/.yaml`	Recursive under apps/

📚 Resources

📦 npm: helm-env-delta

🐙 GitHub: BCsabaEngine/helm-env-delta

🐛 Issues: GitHub Issues

📄 License: ISC

🎉 Success Stories

Typical adoption timeline:

Week 1: Install, create basic config, dry-run on one service
Week 2: Expand to 5 services, add skipPath rules
Week 3: Add stop rules (catch first bug!)
Week 4: Standardize YAML formatting
Month 2: Full adoption for all services

Results:

⏱️ Sync time: 2 hours/week → 10 minutes/week
🐛 Production incidents from sync errors: Zero
😊 Team satisfaction: High

Built for DevOps and Platform teams managing multi-environment Kubernetes and Helm deployments.

Made with ❤️ by BCsabaEngine

Name		Name	Last commit message	Last commit date
Latest commit History 50 Commits
.claude/commands		.claude/commands
.github/workflows		.github/workflows
.vscode		.vscode
bin		bin
example		example
src		src
test		test
.gitignore		.gitignore
.npmrc		.npmrc
.prettierignore		.prettierignore
.prettierrc		.prettierrc
CHANGELOG.md		CHANGELOG.md
CLAUDE.md		CLAUDE.md
CONTRIBUTING.md		CONTRIBUTING.md
FAQ.md		FAQ.md
LICENSE		LICENSE
README.md		README.md
eslint.config.mjs		eslint.config.mjs
package-lock.json		package-lock.json
package.json		package.json
tsconfig.json		tsconfig.json
vitest.config.ts		vitest.config.ts

License

BCsabaEngine/helm-env-delta

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🚀 HelmEnvDelta

👤 Who Is This For?

💡 Why Teams Love HelmEnvDelta

✨ Key Features

📥 Installation

🎯 Quick Start

1️⃣ Create Config

2️⃣ Preview Changes

3️⃣ Execute Sync

4️⃣ Review in Browser

5️⃣ Get Smart Suggestions (Optional)

🎬 Real-World Use Cases

🏢 Multi-Service GitOps

🚨 Prevent Production Incidents

📐 Standardize Formatting

🎓 Live Examples

📁 Example 1: Config Inheritance

🚦 Example 2: Stop Rules

⛓️ Example 3: Multi-Environment Chain

🗑️ Example 4: Prune Mode

📦 Example 5: External Files

📌 Example 6: Fixed Values

🎨 Example 7: Format-Only Mode

💡 Smart Configuration Suggestions (Heuristic)

How It Works

Example Output

When to Use

⚙️ Configuration Reference

🎯 Core Settings

🔒 Path Filtering (skipPath)

Filter Expressions (Skip by Name)

📌 Fixed Values (fixedValues)

🔄 Transformations

Inline Transforms (Regex)

File-Based Transforms (Literal)

🛡️ Stop Rules

Inline Stop Rules

File-Based Stop Rules

🎨 Output Formatting

🔗 Config Inheritance

🖥️ CLI Reference

Commands

Options

Examples

🔄 Typical Workflow

🏆 Why Choose HelmEnvDelta?

🆚 Compared to Alternatives

💪 Benefits

📊 JSON Output for CI/CD

🔧 Advanced Features

🧠 Structural Comparison

🔍 Pattern Usage Validation

🔀 Deep Merge

🆘 Common Issues

❓ Source and destination folders cannot be the same

❓ Stop rule violations blocking sync

❓ Transforms not applying

❓ JSONPath syntax errors

❓ Glob patterns not matching

📚 Resources

🎉 Success Stories

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