feat(corda): prometheus exporter metrics integration

        Primary Change
        ---
        1. The corda ledger connector plugin now includes the prometheus metrics exporter integration
        2. OpenAPI spec now has api endpoint for getting the prometheus metrics

        Refactorings that were also necessary to incorporate 1) and 2)
        ------
        3. GetPrometheusMetricsV1 class is created to handle the corresponding api endpoint
        4. IPluginLedgerConnectorCordaOptions interface in PluginLedgerConnectorCorda class now has a prometheusExporter object optional field
        5. The PluginLedgerConnectorCorda class has relevant functions to incorporate prometheus exporter
        6. Updated Readme.md about the prometheus exporter
        7. Updated the test case located at packages/cactus-plugin-ledger-connector-corda/src/test/typescript/integration/deploy-cordapp-jars-to-nodes.test.ts
        8. Updated the OpenAPI spec file to have run-transaction endpoint which currently returns NOT_IMPLEMENTED with 501 code.

Resolve hyperledger-cacti#535

Signed-off-by: Jagpreet Singh Sasan <jagpreet.singh.sasan@accenture.com>

packages/cactus-plugin-ledger-connector-corda/README.md

@@ -2,6 +2,41 @@
 
 > TODO: description
 
+### Usage Prometheus
+The prometheus exporter object is initialized in the `PluginLedgerConnectorCorda` class constructor itself, so instantiating the object of the `PluginLedgerConnectorCorda` class, gives access to the exporter object.
+You can also initialize the prometheus exporter object seperately and then pass it to the `IPluginLedgerConnectorCordaOptions` interface for `PluginLedgerConnectoFabric` constructor.
+
+`getPrometheusExporterMetricsEndpointV1` function returns the prometheus exporter metrics, currently displaying the total transaction count, which currently increments everytime the `transact()` method of the `PluginLedgerConnectorCorda` class is called.
+
+### Prometheus Integration
+To use Prometheus with this exporter make sure to install [Prometheus main component](https://prometheus.io/download/).
+Once Prometheus is setup, the corresponding scrape_config needs to be added to the prometheus.yml
+
+```(yaml)
+- job_name: 'fabric_ledger_connector_exporter'
+  metrics_path: api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/get-prometheus-exporter-metrics
+  scrape_interval: 5s
+  static_configs:
+    - targets: ['{host}:{port}']
+```
+
+Here the `host:port` is where the prometheus exporter metrics are exposed. The test cases (For example, packages/cactus-plugin-ledger-connector-corda/src/test/typescript/integration/deploy-cordapp-jars-to-nodes.test.ts) exposes it over `0.0.0.0` and a random port(). The random port can be found in the running logs of the test case and looks like (42379 in the below mentioned URL)
+`Metrics URL: http://0.0.0.0:42379/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/get-prometheus-exporter-metrics`
+
+Once edited, you can start the prometheus service by referencing the above edited prometheus.yml file.
+On the prometheus graphical interface (defaulted to http://localhost:9090), choose **Graph** from the menu bar, then select the **Console** tab. From the **Insert metric at cursor** drop down, select **cactus_corda_total_tx_count** and click **execute**
+
+### Helper code
+
+###### response.type.ts
+This file contains the various responses of the metrics.
+
+###### data-fetcher.ts
+This file contains functions encasing the logic to process the data points
+
+###### metrics.ts
+This file lists all the prometheus metrics and what they are used for.
+
 ## Usage
 
 Take a look at how the API client can be used to run transactions on a corda ledger:

packages/cactus-plugin-ledger-connector-corda/package.json

@@ -89,6 +89,7 @@
     "@hyperledger/cactus-core-api": "0.4.1",
     "axios": "0.21.1",
     "express-openapi-validator": "4.10.5",
+    "prom-client": "13.0.0",
     "internal-ip": "6.2.0",
     "joi": "14.3.1",
     "node-ssh": "11.1.0",

packages/cactus-plugin-ledger-connector-corda/src/main-server/kotlin/gen/kotlin-spring/src/main/kotlin/org/hyperledger/cactus/plugin/ledger/connector/corda/server/api/ApiPluginLedgerConnectorCorda.kt

@@ -59,6 +59,15 @@ class ApiPluginLedgerConnectorCordaController(@Autowired(required = true) val se
     }
 
 
+    @GetMapping(
+        value = ["/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/get-prometheus-exporter-metrics"],
+        produces = ["text/plain"]
+    )
+    fun getPrometheusExporterMetricsV1(): ResponseEntity<kotlin.String> {
+        return ResponseEntity(service.getPrometheusExporterMetricsV1(), HttpStatus.valueOf(200))
+    }
+
+
     @PostMapping(
         value = ["/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/invoke-contract"],
         produces = ["application/json"],
@@ -90,4 +99,13 @@ class ApiPluginLedgerConnectorCordaController(@Autowired(required = true) val se
 ): ResponseEntity<List<NodeInfo>> {
         return ResponseEntity(service.networkMapV1(body), HttpStatus.valueOf(200))
     }
+
+
+    @GetMapping(
+        value = ["/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/run-transaction"],
+        produces = ["text/plain"]
+    )
+    fun runTransactionV1(): ResponseEntity<kotlin.String> {
+        return ResponseEntity(service.runTransactionV1(), HttpStatus.valueOf(200))
+    }
 }

packages/cactus-plugin-ledger-connector-corda/src/main-server/kotlin/gen/kotlin-spring/src/main/kotlin/org/hyperledger/cactus/plugin/ledger/connector/corda/server/api/ApiPluginLedgerConnectorCordaService.kt

@@ -16,9 +16,13 @@ interface ApiPluginLedgerConnectorCordaService {
 
 	fun diagnoseNodeV1(diagnoseNodeV1Request: DiagnoseNodeV1Request?): DiagnoseNodeV1Response
 
+	fun getPrometheusExporterMetricsV1(): kotlin.String
+
 	fun invokeContractV1(invokeContractV1Request: InvokeContractV1Request?): InvokeContractV1Response
 
 	fun listFlowsV1(listFlowsV1Request: ListFlowsV1Request?): ListFlowsV1Response
 
 	fun networkMapV1(body: kotlin.Any?): List<NodeInfo>
+
+	fun runTransactionV1(): kotlin.String
 }

packages/cactus-plugin-ledger-connector-corda/src/main/json/openapi.json

@@ -721,6 +721,14 @@
                         "$ref": "#/components/schemas/NodeDiagnosticInfo"
                     }
                 }
+            },
+            "PrometheusExporterMetricsResponse": {
+                "type": "string",
+                "nullable": false
+            },
+            "RunTransactionResponse": {
+                "type": "string",
+                "nullable": false
             }
         }
     },
@@ -904,6 +912,56 @@
                     }
                 }
             }
+        },
+        "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/run-transaction": {
+            "get": {
+                "x-hyperledger-cactus": {
+                    "http": {
+                        "verbLowerCase": "get",
+                        "path": "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/run-transaction"
+                    }
+                },
+                "operationId": "runTransactionV1",
+                "summary": "Runs a transaction on a Corda ledger.",
+                "parameters": [],
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "content": {
+                            "text/plain": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/RunTransactionResponse"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/get-prometheus-exporter-metrics": {
+            "get": {
+                "x-hyperledger-cactus": {
+                    "http": {
+                        "verbLowerCase": "get",
+                        "path": "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-corda/get-prometheus-exporter-metrics"
+                    }
+                },
+                "operationId": "getPrometheusExporterMetricsV1",
+                "summary": "Get the Prometheus Metrics",
+                "parameters": [],
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "content": {
+                            "text/plain": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/PrometheusExporterMetricsResponse"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
         }
     }
 }