feat: Allow custom prometheus info metric

src/main/java/com/ibm/watson/modelmesh/Metrics.java

@@ -155,7 +155,7 @@ final class PrometheusMetrics implements Metrics {
         private final boolean shortNames;
         private final EnumMap<Metric, Collector> metricsMap = new EnumMap<>(Metric.class);
 
-        public PrometheusMetrics(Map<String, String> params) throws Exception {
+        public PrometheusMetrics(Map<String, String> params, Map<String, String> customParams) throws Exception {
             int port = 2112;
             boolean shortNames = true;
             boolean https = true;
@@ -230,6 +230,17 @@ public PrometheusMetrics(Map<String, String> params) throws Exception {
                 }
             }
 
+            // Custom info metrics
+            if (!customParams.isEmpty()){
+                Gauge customMetrics = Gauge.build()
+                        .name(customParams.get("metric_name"))
+                        .help("Info Metrics")
+                        .labelNames("deployment", "slot", "component", "group")
+                        .create();
+                customMetrics.labels(customParams.get("deployment"), customParams.get("slot"), customParams.get("component"), customParams.get("group"));
+                registry.register(customMetrics);
+            }
+
             this.metricServer = new NettyServer(registry, port, https);
             this.shortNames = shortNames;
 

src/main/java/com/ibm/watson/modelmesh/ModelMesh.java

@@ -883,7 +883,9 @@ protected final TProcessor initialize() throws Exception {
 //    }
 
     // "type" or "type:p1=v1;p2=v2;...;pn=vn"
-    private static final Pattern METRICS_CONFIG_PATT = Pattern.compile("([a-z]+)(:\\w+=[^;]+(?:;\\w+=[^;]+)*)?");
+    private static final Pattern METRICS_CONFIG_PATT = Pattern.compile("([a-z;]+)(:\\w+=[^;]+(?:;\\w+=[^;]+)*)?");
+    // "metric_name" or "metric:name;l1=v1,l2=v2,...,ln=vn,"
+    private static final Pattern CUSTOM_METRIC_CONFIG_PATT = Pattern.compile("([a-z_:]+);(\\w+=[^;]+(?:;\\w+=[^,]+)*)?");
 
     private static Metrics setUpMetrics() throws Exception {
         if (System.getenv("MM_METRICS_STATSD_PORT") != null || System.getenv("MM_METRICS_PROMETHEUS_PORT") != null) {
@@ -916,12 +918,34 @@ private static Metrics setUpMetrics() throws Exception {
                 params.put(kv[0], kv[1]);
             }
         }
+        String customMetricConfig = getStringParameter(MMESH_CUSTOM_ENV_VAR, null);
+        Map<String, String> customParams;
+        if (customMetricConfig == null) {
+            logger.info("{} returned null", MMESH_CUSTOM_ENV_VAR);
+            customParams = Collections.emptyMap();
+        } else {
+            logger.info("{} set to \"{}\"", MMESH_CUSTOM_ENV_VAR, customMetricConfig);
+            Matcher customMetricMatcher = CUSTOM_METRIC_CONFIG_PATT.matcher(customMetricConfig);
+            if (!customMetricMatcher.matches()) {
+                throw new Exception("Invalid metrics configuration provided in env var " + MMESH_CUSTOM_ENV_VAR + ": \""
+                                    + customMetricConfig + "\"");
+            }
+            String name = customMetricMatcher.group(1);
+            String customParamString = customMetricMatcher.group(2);
+
+            customParams = new HashMap<>();
+            customParams.put("metric_name", name);
+            for (String customParm : customParamString.substring(0).split(",")) {
+                String[] kv = customParm.split("=");
+                customParams.put(kv[0], kv[1]);
+            }
+        }
         try {
             switch (type.toLowerCase()) {
             case "statsd":
                 return new Metrics.StatsDMetrics(params);
             case "prometheus":
-                return new Metrics.PrometheusMetrics(params);
+                return new Metrics.PrometheusMetrics(params, customParams);
             case "disabled":
                 logger.info("Metrics publishing is disabled (env var {}={})", MMESH_METRICS_ENV_VAR, metricsConfig);
                 return Metrics.NO_OP_METRICS;

src/main/java/com/ibm/watson/modelmesh/ModelMeshEnvVars.java

@@ -46,6 +46,7 @@ private ModelMeshEnvVars() {}
     public static final String LOAD_FAILURE_EXPIRY_ENV_VAR = "MM_LOAD_FAILURE_EXPIRY_TIME_MS";
 
     public static final String MMESH_METRICS_ENV_VAR = "MM_METRICS";
+    public static final String MMESH_CUSTOM_ENV_VAR = "MM_INFO_METRICS";
 
     public static final String LOG_EACH_INVOKE_ENV_VAR = "MM_LOG_EACH_INVOKE";
     public static final String SEND_DEST_ID_ENV_VAR = "MM_SEND_DEST_ID";

src/test/java/com/ibm/watson/modelmesh/ModelMeshMetricsTest.java

@@ -70,7 +70,9 @@ protected int requestCount() {
 
     @Override
     protected Map<String, String> extraEnvVars() {
-        return  ImmutableMap.of("MM_METRICS", "prometheus:port=" + METRICS_PORT + ";scheme=" + SCHEME);
+        return  ImmutableMap.of(
+                "MM_METRICS", "prometheus:port=" + METRICS_PORT + ";scheme=" + SCHEME,
+                "MM_INFO_METRICS", "assistant_deployment_info:relabel;deployment=DEPLOYMENT_NAME,slot=SLOT_NAME,component=COMPONENT_NAME,group=GROUP_NAME");
     }
 
     @Test
@@ -84,7 +86,7 @@ public void metricsTest() throws Exception {
 
             // verify not found status
             ModelStatusInfo status = manageModels.getModelStatus(GetStatusRequest.newBuilder()
-                    .setModelId("i don't exist").build());
+                    .setModelId("I don't exist").build());
 
             assertEquals(ModelStatus.NOT_FOUND, status.getStatus());
             assertEquals(0, status.getErrorsCount());
@@ -198,5 +200,9 @@ public void verifyMetrics() throws Exception {
         assertEquals(0.0, metrics.get("jvm_buffer_pool_used_buffers{pool=\"mapped\",}")); // mmapped memory not used
         assertTrue(metrics.containsKey("jvm_gc_collection_seconds_sum{gc=\"G1 Young Generation\",}"));
         assertTrue(metrics.containsKey("jvm_memory_bytes_committed{area=\"heap\",}"));
+
+        // Info metrics
+        assertTrue(metrics.containsKey("assistant_deployment_info:relabel{deployment=\"DEPLOYMENT_NAME\",slot=\"SLOT_NAME\",component=\"COMPONENT_NAME\",group=\"GROUP_NAME\",}"));
+        assertEquals(0.0, metrics.get("assistant_deployment_info:relabel{deployment=\"DEPLOYMENT_NAME\",slot=\"SLOT_NAME\",component=\"COMPONENT_NAME\",group=\"GROUP_NAME\",}"));
     }
 }