majiayu000 Harness Expert Skill
Expert knowledge of Harness template types, expression language, pipeline patterns, and deployment strategies.
Harness Template Types
1. Step Templates
Purpose: Reusable step configurations across pipelines
Types:
- ShellScript - Execute bash/PowerShell scripts
- Run - Container step with image/command
- K8sDeploy - Kubernetes deployments
- Http - HTTP calls/webhooks
- Approval - Manual approval gates
- ServiceNow - ServiceNow integration
- Custom - Custom step plugins
Template Structure:
template:
name: Deploy to Kubernetes
type: Step
spec:
type: K8sDeploy
spec:
service: <+input>
environment: <+input>
kubernetesCluster: <+input>
namespace: <+input>
releaseName: <+input>
timeout: <+input.deployment_timeout>
skipDryRun: false
allowNoFilesFound: false
delegateSelectors:
- <+input.delegate_selector>
Runtime Inputs (Required):
templateInputs:
spec:
service:
serviceRef: <+input.service_name>
environment:
environmentRef: <+input.environment_name>
kubernetesCluster:
clusterId: <+input.cluster_id>
namespace: <+input.k8s_namespace>
releaseName: <+input.release_name>
2. Stage Templates
Purpose: Reusable stage definitions with multiple steps
Template Structure:
template:
name: Deploy Stage Template
type: Stage
spec:
type: Deployment
spec:
service:
serviceRef: <+input.service_ref>
infrastructure:
infrastructureDefinition:
type: <+input.infra_type> # Kubernetes, AWS, GCP, etc.
spec: <+input.infra_spec>
execution:
steps:
- step:
name: Deploy
identifier: deploy
type: K8sDeploy
spec:
service: <+input.service_ref>
environment: <+input.environment_ref>
- step:
name: Verify
identifier: verify
type: ShellScript
spec:
script: <+input.verify_script>
3. Pipeline Templates
Purpose: Full pipeline definitions with approval gates, notifications, conditions
Template Structure:
template:
name: Complete CI/CD Pipeline
type: Pipeline
spec:
stages:
- stage:
name: Build
identifier: build
type: CI
spec:
codebase:
repoName: <+input.repo_name>
branch: <+input.branch>
build:
type: Docker
spec:
dockerfile: Dockerfile
registryConnector: <+input.registry_connector>
- stage:
name: Deploy Dev
identifier: deploy_dev
type: Deployment
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: dev
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.dev_cluster_id>
- stage:
name: Approval
identifier: approval
type: Approval
spec:
approvalStepType: ShellScript
script: echo "Deploying to production..."
- stage:
name: Deploy Prod
identifier: deploy_prod
type: Deployment
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: prod
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.prod_cluster_id>
Runtime Inputs (<+input>) Syntax
Basic Input Declaration
spec:
service:
serviceRef: <+input> # Required, user must provide
timeout: <+input.deployment_timeout> # Optional with variable name
replicas: <+input | default(3)> # With default value
Input Types & Examples
String Input:
image: <+input>
service: <+input.service_name>
Number Input:
timeout: <+input.timeout_minutes>
replicas: <+input | default(3)>
Boolean Input:
skip_tests: <+input | default(false)>
enable_monitoring: <+input>
List/Array Input:
environments: <+input.env_list>
delegate_selectors: <+input.selectors>
Object Input:
infrastructure: <+input.infra_spec>
Conditional Inputs
# Only required if another input is true
{{#if use_custom_image}}
image: <+input.custom_image>
{{/if}}
# Conditional with expression
<+if>
conditions:
- key: environment
operator: equals
value: production
then: <+input.prod_cluster>
else: <+input.dev_cluster>
</+if>
Expression Language Syntax
Pipeline-Level Expressions
# Access pipeline metadata
<+pipeline.name> # Pipeline name
<+pipeline.identifier> # Pipeline identifier
<+pipeline.executionId> # Execution ID
<+pipeline.triggeredBy> # Who triggered it
<+pipeline.startTs> # Start timestamp
<+pipeline.sequenceNumber> # Execution sequence
Stage-Level Expressions
# Access stage metadata
<+stage.name> # Stage name
<+stage.identifier> # Stage identifier
<+stage.status> # Stage status (Success, Failed, etc.)
<+stage.type> # Stage type (CI, Deployment, etc.)
# Stage variables
<+stage.variables.VARIABLE_NAME> # Stage variable
<+stageArtifacts.IMAGE_ID> # Output artifacts
Step-Level Expressions
# Access step outputs
<+steps.STEP_ID.output.outputKey> # Step output variable
<+steps.build_docker.output.image> # Docker image from build step
<+steps.deploy.status> # Step execution status
# Example
<+steps.deploy.deploymentStatuses> # Deployment status details
Environment Variables
<+env.JIRA_URL> # Environment variable
<+env.DOCKER_REGISTRY> # From infrastructure
# Example in script
- step:
type: ShellScript
spec:
script: |
echo "Registry: <+env.DOCKER_REGISTRY>"
docker push <+env.DOCKER_REGISTRY>/myapp
Secret References
# Retrieve secrets
<+secrets.getValue("my_secret")> # Simple secret
<+secrets.getValue("vault://prod/db_pwd")> # Vault path
# Example
- step:
type: ShellScript
spec:
environmentVariables:
DB_PASSWORD: <+secrets.getValue("database_password")>
Artifact & Output Expressions
# Artifacts from previous stages
<+artifact.image> # Primary artifact
<+artifact.imageTag> # Image tag
<+artifacts.COLLECTOR.IMAGE_ID> # Named artifact
# Example in deploy
- step:
type: K8sDeploy
spec:
image: <+artifact.image>:<+artifact.imageTag>
service: <+input.service_ref>
Pipeline Patterns
Pattern 1: CI/CD Standard
Description: Standard continuous integration and deployment
Flow: Build → Test → Deploy Dev → Approval → Deploy Prod
template:
name: Standard CI/CD
type: Pipeline
spec:
stages:
# Stage 1: Build
- stage:
name: Build
identifier: build
type: CI
spec:
codebase:
repoName: <+input.repo_name>
branch: <+input.branch>
build:
type: Docker
spec:
dockerfile: Dockerfile
registryConnector: <+input.docker_connector>
imageName: <+input.image_name>
imageTag: <+artifact.imageTag>
# Stage 2: Test
- stage:
name: Test
identifier: test
type: CI
depends:
on:
- build
spec:
build:
type: Container
spec:
image: <+steps.build.output.image>
command: npm test -- --coverage
# Stage 3: Deploy Dev
- stage:
name: Deploy Dev
identifier: deploy_dev
type: Deployment
depends:
on:
- test
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: dev
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.dev_cluster>
execution:
steps:
- step:
type: K8sDeploy
spec:
service: <+input.service_ref>
image: <+artifact.image>
# Stage 4: Manual Approval
- stage:
name: Approval for Production
identifier: approval
type: Approval
depends:
on:
- deploy_dev
spec:
approvalStepType: Manual
approvers:
- <+input.approver_group>
# Stage 5: Deploy Production
- stage:
name: Deploy Production
identifier: deploy_prod
type: Deployment
depends:
on:
- approval
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: prod
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.prod_cluster>
execution:
steps:
- step:
type: K8sDeploy
spec:
service: <+input.service_ref>
image: <+artifact.image>
Pattern 2: GitOps with ArgoCD
Description: GitOps pattern using Argo CD for deployments
Flow: Build → Push Manifest → Trigger ArgoCD → Verify
template:
name: GitOps CI/CD Pipeline
type: Pipeline
spec:
stages:
# Stage 1: Build Docker Image
- stage:
name: Build
identifier: build
type: CI
spec:
codebase:
repoName: <+input.repo_name>
branch: <+input.branch>
build:
type: Docker
spec:
dockerfile: Dockerfile
registryConnector: <+input.docker_connector>
imageName: <+input.image_name>
# Stage 2: Update Manifest Repository
- stage:
name: Update Manifests
identifier: update_manifests
type: CI
depends:
on:
- build
spec:
steps:
- step:
type: Run
spec:
container:
image: ubuntu:22.04
shell: Bash
script: |
git clone <+input.manifest_repo> manifests
cd manifests
sed -i "s|IMAGE_TAG|<+artifact.imageTag>|g" k8s/deployment.yaml
git add k8s/deployment.yaml
git commit -m "Update image to <+artifact.imageTag>"
git push origin main
# Stage 3: Trigger ArgoCD Sync
- stage:
name: Deploy via ArgoCD
identifier: deploy_argocd
type: Deployment
depends:
on:
- update_manifests
spec:
steps:
- step:
type: Http
spec:
url: <+input.argocd_api_url>/api/v1/applications/<+input.app_name>/sync
method: Post
headers:
Authorization: Bearer <+secrets.getValue("argocd_token")>
requestBody: |
{
"syncPolicy": {
"syncStrategy": {
"argo": {}
}
}
}
# Stage 4: Verify Deployment
- stage:
name: Verify
identifier: verify
type: Deployment
depends:
on:
- deploy_argocd
spec:
steps:
- step:
type: ShellScript
spec:
script: |
kubectl rollout status deployment/<+input.app_name> \
-n <+input.namespace> \
--timeout=5m
Pattern 3: Canary Deployment
Description: Gradual traffic shift with automated verification
Flow: Deploy Canary (5%) → Verify → Increment Traffic (25%) → Verify → Full Deploy
template:
name: Canary Deployment Pattern
type: Pipeline
spec:
stages:
# Stage 1: Deploy Canary (5% traffic)
- stage:
name: Deploy Canary
identifier: deploy_canary
type: Deployment
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: prod
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.prod_cluster>
execution:
steps:
- step:
type: K8sDeploy
spec:
canaryStrategy:
enabled: true
canaryPercentage: 5
service: <+input.service_ref>
image: <+artifact.image>
# Stage 2: Verify Canary Metrics
- stage:
name: Verify Canary
identifier: verify_canary
type: Deployment
depends:
on:
- deploy_canary
spec:
steps:
- step:
type: ShellScript
spec:
script: |
# Check error rate, latency, etc.
kubectl logs -l version=canary -n <+input.namespace> \
--since=10m | grep ERROR | wc -l > /tmp/errors
ERRORS=$(cat /tmp/errors)
if [ $ERRORS -gt <+input.error_threshold> ]; then
exit 1
fi
# Stage 3: Increment Traffic (25%)
- stage:
name: Increment Traffic
identifier: increment_traffic
type: Deployment
depends:
on:
- verify_canary
spec:
steps:
- step:
type: ShellScript
spec:
script: |
kubectl patch vs <+input.service_ref> -n <+input.namespace> \
-p '{"spec":{"hosts":[{"name":"*","http":[{"match":[{"uri":{"regex":".*"}}],"route":[{"destination":{"host":"<+input.service_ref>","subset":"canary"},"weight":25}]}]}]}}'
# Stage 4: Verify Again
- stage:
name: Verify Increment
identifier: verify_increment
type: Deployment
depends:
on:
- increment_traffic
spec:
steps:
- step:
type: ShellScript
spec:
script: |
sleep 300 # Wait 5 minutes
# Same verification logic
# Stage 5: Full Deployment
- stage:
name: Deploy Full
identifier: deploy_full
type: Deployment
depends:
on:
- verify_increment
spec:
steps:
- step:
type: K8sDeploy
spec:
service: <+input.service_ref>
image: <+artifact.image>
canaryStrategy:
enabled: true
canaryPercentage: 100
Pattern 4: Blue-Green Deployment
Description: Two identical production environments with instant switching
Flow: Build → Deploy to Green (inactive) → Verify → Switch Traffic → Cleanup Blue
template:
name: Blue-Green Deployment Pattern
type: Pipeline
spec:
variables:
- name: active_color
type: String
default: blue
- name: inactive_color
type: String
default: green
stages:
# Stage 1: Deploy to Inactive Environment
- stage:
name: Deploy to Inactive
identifier: deploy_inactive
type: Deployment
spec:
service:
serviceRef: <+input.service_ref>
environment:
environmentRef: <+pipeline.variables.inactive_color>
infrastructure:
infrastructureDefinition:
type: Kubernetes
spec:
clusterId: <+input.prod_cluster>
execution:
steps:
- step:
type: K8sDeploy
spec:
service: <+input.service_ref>
image: <+artifact.image>
# Stage 2: Run Smoke Tests
- stage:
name: Smoke Tests
identifier: smoke_tests
type: CI
depends:
on:
- deploy_inactive
spec:
steps:
- step:
type: Run
spec:
container:
image: postman/newman
shell: Bash
script: |
newman run tests/smoke-collection.json \
--environment env-<+pipeline.variables.inactive_color>.json \
--reporters cli,json
# Stage 3: Manual Approval for Switch
- stage:
name: Approve Traffic Switch
identifier: approve_switch
type: Approval
depends:
on:
- smoke_tests
spec:
approvalStepType: Manual
approvers:
- <+input.approver_group>
# Stage 4: Switch Traffic
- stage:
name: Switch Traffic
identifier: switch_traffic
type: Deployment
depends:
on:
- approve_switch
spec:
steps:
- step:
type: ShellScript
spec:
script: |
# Switch load balancer/service to point to inactive environment
kubectl patch service <+input.service_ref> \
-n production \
-p '{"spec":{"selector":{"version":"<+pipeline.variables.inactive_color>"}}}'
# Stage 5: Verify Active Environment
- stage:
name: Verify Active
identifier: verify_active
type: Deployment
depends:
on:
- switch_traffic
spec:
steps:
- step:
type: ShellScript
spec:
script: |
for i in {1..30}; do
STATUS=$(curl -s -o /dev/null -w "%{http_code}" <+input.prod_url>/health)
if [ $STATUS -eq 200 ]; then
echo "Health check passed"
exit 0
fi
sleep 10
done
exit 1
# Stage 6: Cleanup Old Environment
- stage:
name: Cleanup
identifier: cleanup
type: Deployment
depends:
on:
- verify_active
spec:
steps:
- step:
type: ShellScript
spec:
script: |
kubectl scale deployment <+input.service_ref>-<+pipeline.variables.active_color> \
-n production \
--replicas=0
Template Versioning Best Practices
Version Format
MAJOR.MINOR.PATCH
- MAJOR: Breaking changes (input names change, outputs change)
- MINOR: New optional inputs or non-breaking changes
- PATCH: Bug fixes, documentation updates
Version Declaration
template:
name: Deploy Service
identifier: deploy_service
versionLabel: "2.1.0"
spec:
# Template specification
Using Versioned Templates
# Always use specific version in production
stages:
- stage:
template:
templateRef: deploy_service
versionLabel: "2.1.0" # Explicit version
templateInputs:
spec:
service: <+input.service_ref>
Changelog Maintenance
## Version 2.1.0 (2024-01-15)
- Added: Support for custom health checks
- Added: Optional monitoring setup
- Improved: Error messages for common issues
- Fixed: Timeout handling in K8s deployments
## Version 2.0.0 (2024-01-01) - BREAKING
- Changed: Input name from 'cluster' to 'clusterId'
- Changed: Stage type from 'Deploy' to 'Deployment'
- Removed: Legacy inline script support
## Version 1.0.0 (2023-12-01)
- Initial release
Common Step Configurations
K8s Deployment Step
- step:
name: Deploy to Kubernetes
identifier: k8s_deploy
type: K8sDeploy
spec:
service: <+input.service_ref>
environment: <+input.environment_ref>
kubernetesCluster:
clusterId: <+input.cluster_id>
namespace: <+input.namespace>
releaseName: <+input.release_name>
timeout: 10m
skipDryRun: false
allowNoFilesFound: false
delegateSelectors:
- <+input.delegate_selector>
Container Step (Docker/Podman)
- step:
name: Run Docker Step
identifier: docker_step
type: Run
spec:
container:
image: <+input.image>
shell: Bash
runAsUser: <+input.user>
script: |
#!/bin/bash
set -e
echo "Running test suite..."
npm test -- --coverage
echo "Test passed!"
envVariables:
TEST_ENV: <+input.environment>
API_URL: <+env.API_URL>
outputVariables:
- name: test_result
value: $(cat test-results.json)
HTTP Step
- step:
name: Notify Slack
identifier: notify_slack
type: Http
spec:
url: <+input.slack_webhook>
method: Post
headers:
Content-Type: application/json
requestBody: |
{
"text": "Deployment to <+input.environment> completed!",
"attachments": [
{
"text": "Version: <+artifact.imageTag>"
}
]
}
Approval Step
- step:
name: Manual Approval
identifier: approval
type: Approval
spec:
approvalMessage: Deploy to production?
approvers:
- <+input.approver_group>
approvalTimeout: 1d
autoRejectIfNoActivity: true
isAutoRejectAfterOverride: true