feat: implement comprehensive host configuration management with file-based system

This commit introduces a complete configuration file system for managing Elasticsearch
and Kibana connection parameters, enhancing security and deployment flexibility.

## Key Changes:

### 1. Configuration File System (.gitignore)
- Added .eshost and .kbnhost to .gitignore alongside existing .espass
- Prevents accidental commit of sensitive host information
- Ensures security across development, staging, and production environments

### 2. Makefile Configuration Enhancement
- Updated eshost variable to read from .eshost file with fallback
- Pattern: eshost := $(shell cat .eshost 2>/dev/null || echo "default_host")
- Maintains consistency with existing .espass pattern
- Enables environment-specific Elasticsearch host configuration for Dataflow deployments

### 3. Elasticsearch Setup Script Improvements (scripts/elastic/init.sh)
- Enhanced es_client to read from .eshost file (project root)
- Added kbn_host configuration from .kbnhost file (project root)
- Fallback mechanism ensures backward compatibility
- All configuration variables now follow consistent file-based pattern

### 4. Comprehensive Documentation Updates (readme.md)
- Added step-by-step configuration instructions for all three files
- Clarified usage patterns: makefile vs setup scripts
- Enhanced security notes with detailed file usage breakdown
- Updated step numbering and cross-references
- Added examples for creating configuration files

## Configuration File Usage Matrix:
| File      | Makefile | Setup Scripts | Purpose                |
|-----------|----------|---------------|------------------------|
| .espass   | ✅       | ✅            | Elasticsearch password |
| .eshost   | ✅       | ✅            | Elasticsearch host URL |
| .kbnhost  | ❌       | ✅            | Kibana host URL        |

## Benefits:
- Environment-agnostic deployments (dev/staging/prod)
- Enhanced security through git-ignored configuration files
- Consistent configuration pattern across all components
- Flexible host management without code changes
- Backward compatibility with fallback defaults

## Migration:
Existing deployments continue to work with default values.
New deployments can create configuration files for custom environments.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: bindiego

.gitignore

@@ -2,6 +2,8 @@
 output-*
 debug
 .espass
+.eshost
+.kbnhost
 
 ##########################
 ## Java

makefile

@@ -5,7 +5,7 @@ workerType := e2-standard-2
 workerZone := b
 project := du-hast-mich
 job := gclb
-eshost := https://k8es.ingest.bindiego.com
+eshost := $(shell cat .eshost 2>/dev/null || echo "https://k8es.ingest.bindiego.com")
 esuser := elastic
 espass := $(shell cat .espass 2>/dev/null || echo "changeme")
 esindex := gclb-ingest

readme.md

@@ -50,7 +50,27 @@ echo "your_elasticsearch_password" > .espass
 
 This file is automatically ignored by git (configured in `.gitignore`) to prevent accidentally committing sensitive credentials. Both the makefile and Elasticsearch setup scripts will read the password from this file, with a fallback to "changeme" if the file doesn't exist.
 
-2. Setup GCP
+2. **Configure Elasticsearch Host** 
+
+Create a `.eshost` file in the project root directory containing your Elasticsearch host URL:
+
+```bash
+echo "https://your-elasticsearch-host.com" > .eshost
+```
+
+This file is automatically ignored by git (configured in `.gitignore`) to prevent accidentally committing sensitive host information. Both the makefile and Elasticsearch setup scripts will read the Elasticsearch host from this file, with a fallback to "https://k8es.ingest.bindiego.com" if the file doesn't exist.
+
+3. **Configure Kibana Host** 
+
+Create a `.kbnhost` file in the project root directory containing your Kibana host URL:
+
+```bash
+echo "https://your-kibana-host.com" > .kbnhost
+```
+
+This file is automatically ignored by git (configured in `.gitignore`) to prevent accidentally committing sensitive host information. The Elasticsearch setup script will read the Kibana host from this file, with a fallback to "https://k8na.bindiego.com" if the file doesn't exist.
+
+4. Setup GCP
 
 You could simply run `cd scripts && ./gcp_setup.sh; cd -`, but before that, make sure the parameters on the top have been updated according to your environment, especially the `project` variable, others are really optional.
 
@@ -60,11 +80,16 @@ So this script will
 - Setup a Stackdriver sink (Pubsub) for HTTP load balancers
 - Grant permissions to the Service Account that been used by the sink, who will publish logs to Pubsub topic
 
-3. Setup Elasticsearch & Kibana
+5. Setup Elasticsearch & Kibana
 
 Same as GCP, there is a script can get the job done. Simply run `cd scripts/elastic && ./init.sh; cd -` then you done. Also, make sure you have updated the parameters on the top of the `init.sh` script according to your Elasticsearch setup.
 
-**Note**: The Elasticsearch setup script will automatically use the password from the `.espass` file you created in step 1. Make sure your Elasticsearch cluster is accessible and the credentials are correct.
+**Note**: Both the makefile and Elasticsearch setup script will automatically use:
+- The password from the `.espass` file you created in step 1
+- The Elasticsearch host from the `.eshost` file you created in step 2 
+- The Kibana host from the `.kbnhost` file you created in step 3 
+
+Make sure your Elasticsearch cluster and Kibana instance are accessible and the credentials are correct.
 
 This script will
 
@@ -91,7 +116,11 @@ Double check the paramters passed to the job trigger in `makefile`, then,
 make df
 ```
 
-**Security Note**: All makefile commands automatically use the Elasticsearch password from your `.espass` file, ensuring secure credential handling across development and production environments.
+**Security Note**: Configuration files are automatically used as follows:
+- **Makefile commands**: Use `.espass` and `.eshost` files for Elasticsearch connection
+- **Setup scripts**: Use `.espass`, `.eshost`, and `.kbnhost` files for complete configuration
+
+This ensures secure credential handling and flexible configuration across development and production environments.
 
 ###### FAQs 常见问题
 

scripts/elastic/init.sh

@@ -6,8 +6,8 @@
 pwd=`pwd`
 project_root="$(cd "$pwd/../.." && pwd)"
 
-es_client=https://k8es.client.bindiego.com
-kbn_host=https://k8na.bindiego.com
+es_client=$(cat "$project_root/.eshost" 2>/dev/null || echo "https://k8es.client.bindiego.com")
+kbn_host=$(cat "$project_root/.kbnhost" 2>/dev/null || echo "https://k8na.bindiego.com")
 es_user=elastic
 es_pass=$(cat "$project_root/.espass" 2>/dev/null || echo "changeme")