support system_metrics_cmd in config.properties (#3000)

* support system_metrics_cmd in config.properties

* address security concern

* add log

* update readme

Author: lxning

docs/configuration.md

@@ -297,6 +297,7 @@ e.g. : To allow base URLs `https://s3.amazonaws.com/` and `https://torchserve.py
   * For security reason, `use_env_allowed_urls=true` is required in config.properties to read `allowed_urls` from environment variable.
 * `workflow_store` : Path of workflow store directory. Defaults to model store directory.
 * `disable_system_metrics` : Disable collection of system metrics when set to "true". Default value is "false".
+* `system_metrics_cmd`: The customized system metrics python script name with arguments. For example:`ts/metrics/metric_collector.py --gpu 0`. Default: empty which means TorchServe collects system metrics via "ts/metrics/metric_collector.py --gpu $CUDA_VISIBLE_DEVICES".
 
 **NOTE**
 

frontend/server/src/main/java/org/pytorch/serve/metrics/MetricCollector.java

@@ -7,6 +7,7 @@
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import org.apache.commons.io.IOUtils;
@@ -32,16 +33,23 @@ public MetricCollector(ConfigManager configManager) {
     public void run() {
         try {
             // Collect System level Metrics
-            String[] args = new String[4];
-            args[0] = configManager.getPythonExecutable();
-            args[1] = "ts/metrics/metric_collector.py";
-            args[2] = "--gpu";
-            args[3] = String.valueOf(ConfigManager.getInstance().getNumberOfGpu());
+            List<String> args = new ArrayList<>();
+            args.add(configManager.getPythonExecutable());
+            String systemMetricsCmd = configManager.getSystemMetricsCmd();
+            if (systemMetricsCmd.isEmpty()) {
+                systemMetricsCmd =
+                        String.format(
+                                "%s --gpu %s",
+                                "ts/metrics/metric_collector.py",
+                                String.valueOf(configManager.getNumberOfGpu()));
+            }
+            args.addAll(Arrays.asList(systemMetricsCmd.split("\\s+")));
             File workingDir = new File(configManager.getModelServerHome());
 
             String[] envp = EnvironmentUtils.getEnvString(workingDir.getAbsolutePath(), null, null);
-
-            final Process p = Runtime.getRuntime().exec(args, envp, workingDir); // NOPMD
+            final Process p =
+                    Runtime.getRuntime()
+                            .exec(args.toArray(new String[0]), envp, workingDir); // NOPMD
             ModelManager modelManager = ModelManager.getInstance();
             Map<Integer, WorkerThread> workerMap = modelManager.getWorkers();
             try (OutputStream os = p.getOutputStream()) {

frontend/server/src/main/java/org/pytorch/serve/util/ConfigManager.java

@@ -117,6 +117,7 @@ public final class ConfigManager {
     private static final String MODEL_SNAPSHOT = "model_snapshot";
     private static final String MODEL_CONFIG = "models";
     private static final String VERSION = "version";
+    private static final String SYSTEM_METRICS_CMD = "system_metrics_cmd";
 
     // Configuration default values
     private static final String DEFAULT_TS_ALLOWED_URLS = "file://.*|http(s)?://.*";
@@ -559,6 +560,10 @@ public String getCertificateFile() {
         return prop.getProperty(TS_CERTIFICATE_FILE);
     }
 
+    public String getSystemMetricsCmd() {
+        return prop.getProperty(SYSTEM_METRICS_CMD, "");
+    }
+
     public SslContext getSslContext() throws IOException, GeneralSecurityException {
         List<String> supportedCiphers =
                 Arrays.asList(
@@ -734,7 +739,9 @@ public String dumpConfigurations() {
                 + "\nCPP log config: "
                 + (getTsCppLogConfig() == null ? "N/A" : getTsCppLogConfig())
                 + "\nModel config: "
-                + prop.getProperty(MODEL_CONFIG, "N/A");
+                + prop.getProperty(MODEL_CONFIG, "N/A")
+                + "\nSystem metrics command: "
+                + (getSystemMetricsCmd().isEmpty() ? "default" : getSystemMetricsCmd());
     }
 
     public boolean useNativeIo() {