feat: update node-exporter example for smoother configuration

node-exporter/.gitignore

@@ -1,2 +1,4 @@
 /prometheus-data
 /prometheus.yml
+greptime.env
+greptime.env.bak

node-exporter/README.md

@@ -14,114 +14,33 @@ First of all, let's get a free GreptimeDB service:
 
 1. Obtain a free GreptimeDB service from [GreptimeCloud](https://console.greptime.cloud/).
 2. Click the "Connection Information" button and find the connection string.
-3. Export the necessary environment variables:
+3. Create a `greptime.env` by copy the `greptime.env.sample` and fill with your
+   connection information.
 
 ```shell
-export GREPTIME_HOST="<host>"
-```
-
-```shell
-export GREPTIME_DATABASE="<dbname>"
-```
-
-```shell
-export GREPTIME_USERNAME="<username>"
-```
-
-```shell
-export GREPTIME_PASSWORD="<password>"
+GREPTIME_SCHEME=https
+GREPTIME_PORT=443
+
+## Fill with your connection information
+GREPTIME_HOST=
+GREPTIME_DB=
+GREPTIME_USERNAME=
+GREPTIME_PASSWORD=
 ```
 
 ![Connection](/media/conninfo.png)
 
-## Step 2: Start the Node Exporter
-
-Node Exporter is a Prometheus exporter for hardware and OS metrics exposed by Linus or Darwin kernels.
-
-You can download and run the Node Exporter from its [release page](https://github.com/prometheus/node_exporter/releases). For example, run the following command if your system is `darwin-arm64`:
+## Step 2: Start Node Exporter and Prometheus with Docker Compose
 
-```bash
-curl -fsSL -O https://github.com/prometheus/node_exporter/releases/download/v1.8.2/node_exporter-1.8.2.darwin-arm64.tar.gz
-tar -xvzf node_exporter-1.8.2.darwin-arm64.tar.gz
-cd node_exporter-1.8.2.darwin-arm64
-./node_exporter
-```
-
-The Node Exporter should print several INFO logs:
+We build a docker-compose file to start Prometheus node exporter and Prometheus
+with just one call. Make sure you have `docker` and `docker-compose`
+installed. Run:
 
 ```
-...
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:111 level=info msg="Enabled collectors"
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=boottime
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=cpu
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=diskstats
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=filesystem
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=loadavg
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=meminfo
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=netdev
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=os
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=powersupplyclass
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=textfile
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=thermal
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=time
-ts=2024-07-19T01:46:25.629Z caller=node_exporter.go:118 level=info collector=uname
-ts=2024-07-19T01:46:25.629Z caller=tls_config.go:313 level=info msg="Listening on" address=[::]:9100
-ts=2024-07-19T01:46:25.629Z caller=tls_config.go:316 level=info msg="TLS is disabled." http2=false address=[::]:9100
-...
-```
-
-Now, you can get the current hardware and OS metrics with:
-
-```bash
-curl http://localhost:9100/metrics
-```
-
-## Step 3: Scrape Metrics and Push to GreptimeDB
-
-As shown above, the Node Exporter only exposes an endpoint that you can query the current metrics. To scrape these metrics and push them to the GreptimeDB service, you can either:
-
-1. Start up a Prometheus instance on localhost that's configured to scrape metrics from the running Node Exporter, and remotely write to the GreptimeDB service; or,
-2. If the Node Exporter endpoint can be accessed from publish network, you can open the Web Dashboard of the GreptimeDB service, head to the Workbench tab (`https://<host>.greptime.cloud/dashboard/workbench`), and modify the `prometheus.yml` file to add the config as described below.
-
-Since the Node Exporter started above is running on localhost, this demo chooses the first option.
-
-You can download and run a Prometheus instance from its [release page](https://github.com/prometheus/prometheus/releases). For example, run the following command if your system is `darwin-arm64`:
-
-```bash
-curl -fsSL -O https://github.com/prometheus/prometheus/releases/download/v2.53.1/prometheus-2.53.1.darwin-arm64.tar.gz
-tar -xvzf prometheus-2.53.1.darwin-arm64.tar.gz
-cd prometheus-2.53.1.darwin-arm64
-```
-
-Modify the `prometheus.yml` file with:
-
-> [!TIP]
->
-> If you switch to a new session, you need to re-export the environment variables as in [Step 1](#step-1-set-up-greptimedb-service).
-
-```bash
-cat <<END > prometheus.yml
-global:
-  scrape_interval: 15s
-scrape_configs:
-  - job_name: "node"
-    static_configs:
-      - targets: ["localhost:9100"]
-remote_write:
-  - url: "https://${GREPTIME_HOST}/v1/prometheus/write?db=${GREPTIME_DATABASE}"
-    basic_auth:
-      username: ${GREPTIME_USERNAME}
-      password: ${GREPTIME_PASSWORD}
-END
-```
-
-Start the bridge instance with:
-
-```bash
-./prometheus --config.file=./prometheus.yml
+docker compose up
 ```
 
-## Step 4: Visualize on GreptimeDB Dashboard
+## Step 3: Visualize on GreptimeCloud Dashboard
 
 You can visualize the node mertics from the Web Dashboard:
 
@@ -166,15 +85,3 @@ Choose "Import a dashboard" and then load the Node Exporter Full public template
 Use the data source you just registered, and click "Import". You will be redirected to the final dashboard:
 
 ![Grafana Final Dashboard](media/grafana-final-dashboard.png)
-
-## Bonus: Bootstrap with a Docker Compose oneliner
-
-This demo also provides a [docker-compose.yml](docker-compose.yml) file so that you can set up the whole Node Exporter integration in one line:
-
-Create your own `prometheus.yml` from `prometheus.yml.tpl` by replacing
-placeholders with your GreptimeDB connection information. Start Prometheus/Node
-Exporter/Grafana with docker compose:
-
-```bash
-docker compose up
-```

node-exporter/docker-compose.yml

@@ -1,4 +1,15 @@
 services:
+  envsubst:
+    image: docker.io/widerplan/envsubst
+    command: "-i /config_input/prometheus.yml.tpl -o /config_output/prometheus.yml"
+    volumes:
+      - ./prometheus.yml.tpl:/config_input/prometheus.yml.tpl
+      - config:/config_output
+    env_file:
+      - path: "greptime.env"
+        required: false
+    init: true
+
   node_exporter:
     image: quay.io/prometheus/node-exporter:latest
     container_name: node_exporter
@@ -15,23 +26,17 @@ services:
     networks:
       - demo-network
     volumes:
-      - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
+      - config:/etc/prometheus
     command:
       - '--config.file=/etc/prometheus/prometheus.yml'
       - '--web.enable-lifecycle'
     depends_on:
       - node_exporter
+      - envsubst
     ports:
       - 9090:9090
 
-  grafana:
-    image: docker.io/grafana/grafana:11.1.0
-    ports:
-      - 3000:3000
-    networks:
-      - demo-network
-    restart: always
-
-
 networks:
   demo-network:
+volumes:
+  config:

node-exporter/greptime.env.sample

@@ -0,0 +1,7 @@
+GREPTIME_SCHEME=https
+GREPTIME_PORT=443
+
+GREPTIME_HOST=
+GREPTIME_DB=
+GREPTIME_USERNAME=
+GREPTIME_PASSWORD=