ApplicationSet Quick Reference

One-page cheat sheet for ApplicationSet usage in Kast System.

---

Template Variables Cheat Sheet

Git Files Generator

# Path variables (auto-generated)
{{.path.path}}               # bookrack/the-yaml-life/staging
{{.path.basename}}           # staging
{{.path.filename}}           # conduwuit (no extension!)
{{.path[0]}}                 # bookrack
{{.path[1]}}                 # the-yaml-life
{{.path[2]}}                 # staging

# File content (from YAML)
{{.name}}                    # Any field from the file
{{.namespace}}               # Any nested field
{{.image.tag}}               # Nested access

⚠️ NEVER use {{path}} - it's an object! Use {{.path.path}}

---

Common Patterns

Multi-Source with ValueFiles

sources:
  # Chart source
  - repoURL: https://github.com/org/charts.git
    path: charts/app
    helm:
      valueFiles:
        - $values/{{.path.path}}/{{.path.filename}}.yaml

  # Values source (MUST have ref!)
  - repoURL: https://github.com/org/configs.git
    targetRevision: main
    ref: values  # Creates $values variable

Dynamic Namespace

destination:
  namespace: '{{.namespace | default .path.basename}}'

Conditional Values

helm:
  values: |
    {{- if .replicas }}
    replicas: {{.replicas}}
    {{- else }}
    replicas: 1
    {{- end }}

Exclude Files

files:
  - path: "apps/*.yaml"
  - path: "apps/index.yaml"
    exclude: true  # Boolean, not pattern!

---

Generator Types

Generator	Use Case	Example
Git Files	YAML/JSON files → Apps	Config per environment
Git Directory	Directories → Apps	Helm chart per dir
List	Static list → Apps	Fixed environments
Cluster	ArgoCD clusters → Apps	Multi-cluster deploy
Matrix	Combine generators	Apps × Envs

---

Debugging Commands

# Check ApplicationSet status
kubectl get appset -n argocd
kubectl describe appset my-appset -n argocd

# View generated applications
argocd appset get my-appset

# Check conditions
kubectl get appset my-appset -n argocd -o jsonpath='{.status.conditions}'

# Test file discovery locally
git clone <repo>
find . -path "bookrack/*/staging/*.yaml"

---

Common Errors & Fixes

Error	Cause	Fix
"duplicate name"	Same filename in multiple dirs	Use {{.path.basename}}-{{.path.filename}}
"{{path}} is invalid"	Using object as string	Use {{.path.path}}
"exclude must be boolean"	String pattern in exclude	Use exclude: true on separate path entry
"$values unresolved"	Missing ref field	Add ref: values to source

---

Current Kast System Implementation

File: bookrack/the-yaml-life/intro/staging-appset.yaml

Purpose: Auto-generate summon Apps for all staging/*.yaml files

Fix Needed:

# Current (BROKEN)
valueFiles:
  - $values/{{path}}

# Should be
valueFiles:
  - $values/{{.path.path}}/{{.path.filename}}.yaml

---

Go Template Functions

# String manipulation
{{.name | lower}}                    # lowercase
{{.name | upper}}                    # UPPERCASE
{{.name | replace "_" "-"}}          # replace chars

# Defaults
{{.namespace | default "default"}}   # fallback value

# Conditionals
{{- if eq .env "prod" }}
replicas: 5
{{- else }}
replicas: 1
{{- end }}

# Loops
{{- range .items }}
- name: {{.name}}
{{- end }}

---

Best Practices Checklist

• Use goTemplate: true
• Never use {{path}} directly
• Include ref: values for multi-source
• Add labels for tracking
• Use sync waves for ordering
• Test with single file first
• Document generator logic
• Set specific targetRevision

---

Full Documentation: docs/applicationset-guide.md