feat(fabric): add prometheus exporter

	Primary Change
	--------------

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

	Refactorings that were also necessary to accomodate 1) and 2)
	------------------------------------------------------------

	3. The generate-sdk command now has DateTime mapping to Date (to read Date as Date object instead of string)
	4. GetPrometheusMetricsV1 class is created to handle the corresponding api endpoint
	5. IPluginLedgerConnectorFabricOptions interface in PluginLedgerConnectorFabric class now has a prometheusExporter optional field
	6. The PluginLedgerConnectorFabric class has relevant functions and codes to incorporate prometheus exporter
	7. run-transaction-endpoint-v1.test is changed to incorporate the prometheus exporter for both fabric 1.4.x and 2.x versions
	8. Added Readme.md on the prometheus exporter usage

	Fixes #531

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

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

@@ -1,9 +1,41 @@
 # `@hyperledger/cactus-plugin-ledger-connector-fabric`
 
-> TODO: description
+## Prometheus Exporter
 
-## Usage
+This class creates a prometheus exporter, which scraps the transactions (total transaction count) for the use cases incorporating the use of Fabric connector plugin.
 
+
+### Usage
+The prometheus exporter object is initialized in the `PluginLedgerConnectorFabric` class constructor itself, so instantiating the object of the `PluginLedgerConnectorFabric` class, gives access to the exporter object.
+You can also initialize the prometheus exporter object seperately and then pass it to the `IPluginLedgerConnectorFabricOptions` 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 `PluginLedgerConnectorFabric` 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-fabric/get-prometheus-exporter-metrics
+  scrape_interval: 5s
+  static_configs:
+    - targets: ['{host}:{port}']
 ```
-// TODO: DEMONSTRATE API
-```
+
+Here the `host:port` is where the prometheus exporter metrics are exposed. The test cases (For example, packages/cactus-plugin-ledger-connector-fabric/src/test/typescript/integration/fabric-v1-4-x/run-transaction-endpoint-v1.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-fabric/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_fabric_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.

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

@@ -95,6 +95,7 @@
     "ngo": "2.6.2",
     "node-ssh": "11.0.0",
     "openapi-types": "7.0.1",
+    "prom-client": "13.0.0",
     "temp": "0.9.1",
     "typescript-optional": "2.0.1",
     "uuid": "8.3.0",

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

@@ -286,6 +286,10 @@
                         "type": "string"
                     }
                 }
+            },
+            "PrometheusExporterMetricsResponse": {
+                "type": "string",
+                "nullable": false
             }
         }
     },
@@ -368,6 +372,31 @@
                     }
                 }
             }
+        },
+        "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-fabric/get-prometheus-exporter-metrics": {
+            "get": {
+                "x-hyperledger-cactus": {
+                    "http": {
+                        "verbLowerCase": "get",
+                        "path": "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-fabric/get-prometheus-exporter-metrics"
+                    }
+                },
+                "operationId": "getPrometheusExporterMetricsV1",
+                "summary": "Get the Prometheus Metrics",
+                "parameters": [],
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "content": {
+                            "text/plain": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/PrometheusExporterMetricsResponse"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
         }
     }
 }

packages/cactus-plugin-ledger-connector-fabric/src/main/typescript/generated/openapi/typescript-axios/.openapi-generator-ignore

@@ -24,3 +24,4 @@
 
 git_push.sh
 .npmignore
+.gitignore

packages/cactus-plugin-ledger-connector-fabric/src/main/typescript/generated/openapi/typescript-axios/.openapi-generator/FILES

@@ -1,4 +1,3 @@
-.gitignore
 api.ts
 base.ts
 configuration.ts

packages/cactus-plugin-ledger-connector-fabric/src/main/typescript/generated/openapi/typescript-axios/api.ts

@@ -353,6 +353,42 @@ export const DefaultApiAxiosParamCreator = function (configuration?: Configurati
                 options: localVarRequestOptions,
             };
         },
+        /**
+         * 
+         * @summary Get the Prometheus Metrics
+         * @param {*} [options] Override http request option.
+         * @throws {RequiredError}
+         */
+        getPrometheusExporterMetricsV1: async (options: any = {}): Promise<RequestArgs> => {
+            const localVarPath = `/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-fabric/get-prometheus-exporter-metrics`;
+            // use dummy base URL string because the URL constructor only accepts absolute URLs.
+            const localVarUrlObj = new URL(localVarPath, 'https://example.com');
+            let baseOptions;
+            if (configuration) {
+                baseOptions = configuration.baseOptions;
+            }
+            const localVarRequestOptions = { method: 'GET', ...baseOptions, ...options};
+            const localVarHeaderParameter = {} as any;
+            const localVarQueryParameter = {} as any;
+
+
+
+            const query = new URLSearchParams(localVarUrlObj.search);
+            for (const key in localVarQueryParameter) {
+                query.set(key, localVarQueryParameter[key]);
+            }
+            for (const key in options.query) {
+                query.set(key, options.query[key]);
+            }
+            localVarUrlObj.search = (new URLSearchParams(query)).toString();
+            let headersFromBaseOptions = baseOptions && baseOptions.headers ? baseOptions.headers : {};
+            localVarRequestOptions.headers = {...localVarHeaderParameter, ...headersFromBaseOptions, ...options.headers};
+
+            return {
+                url: localVarUrlObj.pathname + localVarUrlObj.search + localVarUrlObj.hash,
+                options: localVarRequestOptions,
+            };
+        },
         /**
          * 
          * @summary Runs a transaction on a Fabric ledger.
@@ -421,6 +457,19 @@ export const DefaultApiFp = function(configuration?: Configuration) {
                 return axios.request(axiosRequestArgs);
             };
         },
+        /**
+         * 
+         * @summary Get the Prometheus Metrics
+         * @param {*} [options] Override http request option.
+         * @throws {RequiredError}
+         */
+        async getPrometheusExporterMetricsV1(options?: any): Promise<(axios?: AxiosInstance, basePath?: string) => AxiosPromise<string>> {
+            const localVarAxiosArgs = await DefaultApiAxiosParamCreator(configuration).getPrometheusExporterMetricsV1(options);
+            return (axios: AxiosInstance = globalAxios, basePath: string = BASE_PATH) => {
+                const axiosRequestArgs = {...localVarAxiosArgs.options, url: basePath + localVarAxiosArgs.url};
+                return axios.request(axiosRequestArgs);
+            };
+        },
         /**
          * 
          * @summary Runs a transaction on a Fabric ledger.
@@ -454,6 +503,15 @@ export const DefaultApiFactory = function (configuration?: Configuration, basePa
         deployContractGoSourceV1(deployContractGoSourceV1Request?: DeployContractGoSourceV1Request, options?: any): AxiosPromise<DeployContractGoSourceV1Response> {
             return DefaultApiFp(configuration).deployContractGoSourceV1(deployContractGoSourceV1Request, options).then((request) => request(axios, basePath));
         },
+        /**
+         * 
+         * @summary Get the Prometheus Metrics
+         * @param {*} [options] Override http request option.
+         * @throws {RequiredError}
+         */
+        getPrometheusExporterMetricsV1(options?: any): AxiosPromise<string> {
+            return DefaultApiFp(configuration).getPrometheusExporterMetricsV1(options).then((request) => request(axios, basePath));
+        },
         /**
          * 
          * @summary Runs a transaction on a Fabric ledger.
@@ -486,6 +544,17 @@ export class DefaultApi extends BaseAPI {
         return DefaultApiFp(this.configuration).deployContractGoSourceV1(deployContractGoSourceV1Request, options).then((request) => request(this.axios, this.basePath));
     }
 
+    /**
+     * 
+     * @summary Get the Prometheus Metrics
+     * @param {*} [options] Override http request option.
+     * @throws {RequiredError}
+     * @memberof DefaultApi
+     */
+    public getPrometheusExporterMetricsV1(options?: any) {
+        return DefaultApiFp(this.configuration).getPrometheusExporterMetricsV1(options).then((request) => request(this.axios, this.basePath));
+    }
+
     /**
      * 
      * @summary Runs a transaction on a Fabric ledger.

packages/cactus-plugin-ledger-connector-fabric/src/main/typescript/get-prometheus-exporter-metrics/get-prometheus-exporter-metrics-endpoint-v1.ts

@@ -0,0 +1,81 @@
+import { Express, Request, Response } from "express";
+
+import {
+  Logger,
+  LoggerProvider,
+  LogLevelDesc,
+  Checks,
+} from "@hyperledger/cactus-common";
+
+import {
+  IWebServiceEndpoint,
+  IExpressRequestHandler,
+} from "@hyperledger/cactus-core-api";
+
+import OAS from "../../json/openapi.json";
+
+import { registerWebServiceEndpoint } from "@hyperledger/cactus-core";
+
+import { PluginLedgerConnectorFabric } from "../plugin-ledger-connector-fabric";
+
+export interface IGetPrometheusExporterMetricsEndpointV1Options {
+  logLevel?: LogLevelDesc;
+  connector: PluginLedgerConnectorFabric;
+}
+
+export class GetPrometheusExporterMetricsEndpointV1
+  implements IWebServiceEndpoint {
+  private readonly log: Logger;
+
+  constructor(
+    public readonly opts: IGetPrometheusExporterMetricsEndpointV1Options,
+  ) {
+    const fnTag = "GetPrometheusExporterMetricsEndpointV1#constructor()";
+
+    Checks.truthy(opts, `${fnTag} options`);
+    Checks.truthy(opts.connector, `${fnTag} options.connector`);
+
+    this.log = LoggerProvider.getOrCreate({
+      label: "get-prometheus-exporter-metrics-v1",
+      level: opts.logLevel || "INFO",
+    });
+  }
+
+  public getExpressRequestHandler(): IExpressRequestHandler {
+    return this.handleRequest.bind(this);
+  }
+
+  public getPath(): string {
+    return OAS.paths[
+      "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-fabric/get-prometheus-exporter-metrics"
+    ].get["x-hyperledger-cactus"].http.path;
+  }
+
+  public getVerbLowerCase(): string {
+    return OAS.paths[
+      "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-fabric/get-prometheus-exporter-metrics"
+    ].get["x-hyperledger-cactus"].http.verbLowerCase;
+  }
+
+  public registerExpress(app: Express): IWebServiceEndpoint {
+    registerWebServiceEndpoint(app, this);
+    return this;
+  }
+
+  async handleRequest(req: Request, res: Response): Promise<void> {
+    const fnTag = "GetPrometheusExporterMetrics#handleRequest()";
+    const verbUpper = this.getVerbLowerCase().toUpperCase();
+    this.log.debug(`${verbUpper} ${this.getPath()}`);
+
+    try {
+      const resBody = await this.opts.connector.getPrometheusExporterMetrics();
+      res.status(200);
+      res.send(resBody);
+    } catch (ex) {
+      this.log.error(`${fnTag} failed to serve request`, ex);
+      res.status(500);
+      res.statusMessage = ex.message;
+      res.json({ error: ex.stack });
+    }
+  }
+}