feat(besu): add prometheus exporter

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

	1. The besu 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. GetPrometheusMetricsV1 class is created to handle the corresponding api endpoint
	4. IPluginLedgerConnectorBesuOptions interface in PluginLedgerConnectorBesu class now has a prometheusExporter optional field
	5. The PluginLedgerConnectorBesu class has relevant functions and codes to incorporate prometheus exporter
	6. Added Readme.md on the prometheus exporter usage

	Fixes hyperledger-cacti#533

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

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

@@ -8,6 +8,7 @@ This plugin provides `Cactus` a way to interact with Besu networks. Using this w
 
   - [Getting Started](#getting-started)
   - [Usage](#usage)
+  - [Prometheus Exporter](#prometheus-exporter)
   - [Runing the tests](#running-the-tests)
   - [Built With](#built-with)
   - [Contributing](#contributing)
@@ -33,8 +34,6 @@ In the project root folder, run this command to compile the plugin and create th
 npm run tsc
 ```
 
-## Usage
-
 To use this import public-api and create new **PluginFactoryLedgerConnector**. Then use it to create a connector.
 ```typescript
 const factory = new PluginFactoryLedgerConnector({
@@ -80,6 +79,45 @@ enum Web3SigningCredentialType {
 ```
 > Extensive documentation and examples in the [readthedocs](https://readthedocs.org/projects/hyperledger-cactus/) (WIP) 
 
+## Prometheus Exporter
+
+This class creates a prometheus exporter, which scrapes the transactions (total transaction count) for the use cases incorporating the use of Besu connector plugin.
+
+### Usage
+The prometheus exporter object is initialized in the `PluginLedgerConnectorBesu` class constructor itself, so instantiating the object of the `PluginLedgerConnectorBesu` class, gives access to the exporter object.
+You can also initialize the prometheus exporter object seperately and then pass it to the `IPluginLedgerConnectorBesuOptions` interface for `PluginLedgerConnectoBesu` constructor.
+
+`getPrometheusExporterMetricsV1` function returns the prometheus exporter metrics, currently displaying the total transaction count, which currently increments everytime the `transact()` method of the `PluginLedgerConnectorBesu` 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: 'besu_ledger_connector_exporter'
+  metrics_path: api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-besu/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-besu/src/test/typescript/integration/plugin-ledger-connector-besu/deploy-contract/deploy-contract-from-json.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-besu/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_besu_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.
+
 ## Running the tests
 
 To check that all has been installed correctly and that the pugin has no errors run the tests:
@@ -99,4 +137,4 @@ Please review [CONTIRBUTING.md](../../CONTRIBUTING.md) to get started.
 
 This distribution is published under the Apache License Version 2.0 found in the [LICENSE](../../LICENSE) file.
 
-## Acknowledgments 
+## Acknowledgments 

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

@@ -33,7 +33,10 @@
       "ignore": [
         "src/**/generated/*"
       ],
-      "extensions": ["ts", "json"],
+      "extensions": [
+        "ts",
+        "json"
+      ],
       "quiet": true,
       "verbose": false,
       "runOnChangeOnly": true
@@ -87,6 +90,7 @@
     "express": "4.17.1",
     "joi": "14.3.1",
     "openapi-types": "7.0.1",
+    "prom-client": "13.1.0",
     "typescript-optional": "2.0.1",
     "web3": "1.2.7",
     "web3-eea": "0.10.0"

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

@@ -651,6 +651,10 @@
                         "nullable": false
                     }
                 }
+            },
+            "PrometheusExporterMetricsResponse": {
+                "type": "string",
+                "nullable": false
             }
         }
     },
@@ -829,6 +833,31 @@
                     }
                 }
             }
+        },
+        "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-besu/get-prometheus-exporter-metrics": {
+            "get": {
+                "x-hyperledger-cactus": {
+                    "http": {
+                        "verbLowerCase": "get",
+                        "path": "/api/v1/plugins/@hyperledger/cactus-plugin-ledger-connector-besu/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-besu/src/main/typescript/generated/openapi/typescript-axios/api.ts

@@ -784,6 +784,42 @@ 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-besu/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,
+            };
+        },
         /**
          * Obtain signatures of ledger from the corresponding transaction hash.
          * @summary Obtain signatures of ledger from the corresponding transaction hash.
@@ -894,6 +930,19 @@ 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);
+            };
+        },
         /**
          * Obtain signatures of ledger from the corresponding transaction hash.
          * @summary Obtain signatures of ledger from the corresponding transaction hash.
@@ -957,6 +1006,15 @@ export const DefaultApiFactory = function (configuration?: Configuration, basePa
         apiV2BesuInvokeContract(invokeContractV2Request?: InvokeContractV2Request, options?: any): AxiosPromise<InvokeContractV2Response> {
             return DefaultApiFp(configuration).apiV2BesuInvokeContract(invokeContractV2Request, 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));
+        },
         /**
          * Obtain signatures of ledger from the corresponding transaction hash.
          * @summary Obtain signatures of ledger from the corresponding transaction hash.
@@ -1025,6 +1083,17 @@ export class DefaultApi extends BaseAPI {
         return DefaultApiFp(this.configuration).apiV2BesuInvokeContract(invokeContractV2Request, 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));
+    }
+
     /**
      * Obtain signatures of ledger from the corresponding transaction hash.
      * @summary Obtain signatures of ledger from the corresponding transaction hash.

packages/cactus-plugin-ledger-connector-besu/src/main/typescript/plugin-ledger-connector-besu.ts

@@ -59,13 +59,19 @@ import { InvokeContractEndpoint } from "./web-services/invoke-contract-endpoint"
 import { InvokeContractEndpointV2 } from "./web-services/invoke-contract-endpoint-v2";
 import { isWeb3SigningCredentialNone } from "./model-type-guards";
 import { BesuSignTransactionEndpointV1 } from "./web-services/sign-transaction-endpoint-v1";
+import { PrometheusExporter } from "./prometheus-exporter/prometheus-exporter";
+import {
+  GetPrometheusExporterMetricsEndpointV1,
+  IGetPrometheusExporterMetricsEndpointV1Options,
+} from "./web-services/get-prometheus-exporter-metrics-endpoint-v1";
 
 export const E_KEYCHAIN_NOT_FOUND = "cactus.connector.besu.keychain_not_found";
 
 export interface IPluginLedgerConnectorBesuOptions
   extends ICactusPluginOptions {
   rpcApiHttpHost: string;
   pluginRegistry: PluginRegistry;
+  prometheusExporter?: PrometheusExporter;
   logLevel?: LogLevelDesc;
   contractsPath?: string;
 }
@@ -81,6 +87,7 @@ export class PluginLedgerConnectorBesu
     ICactusPlugin,
     IPluginWebService {
   private readonly instanceId: string;
+  public prometheusExporter: PrometheusExporter;
   private readonly log: Logger;
   private readonly web3: Web3;
   private readonly pluginRegistry: PluginRegistry;
@@ -114,6 +121,25 @@ export class PluginLedgerConnectorBesu
     this.instanceId = options.instanceId;
     this.pluginRegistry = options.pluginRegistry;
     this.contractsPath = options.contractsPath;
+    this.prometheusExporter =
+      options.prometheusExporter ||
+      new PrometheusExporter({ pollingIntervalInMin: 1 });
+    Checks.truthy(
+      this.prometheusExporter,
+      `${fnTag} options.prometheusExporter`,
+    );
+
+    this.prometheusExporter.startMetricsCollection();
+  }
+
+  public getPrometheusExporter(): PrometheusExporter {
+    return this.prometheusExporter;
+  }
+
+  public async getPrometheusExporterMetrics(): Promise<string> {
+    const res: string = await this.prometheusExporter.getPrometheusMetrics();
+    this.log.debug(`getPrometheusExporterMetrics() response: %o`, res);
+    return res;
   }
 
   public getInstanceId(): string {
@@ -176,6 +202,15 @@ export class PluginLedgerConnectorBesu
       endpoint.registerExpress(expressApp);
       endpoints.push(endpoint);
     }
+    {
+      const opts: IGetPrometheusExporterMetricsEndpointV1Options = {
+        connector: this,
+        logLevel: this.options.logLevel,
+      };
+      const endpoint = new GetPrometheusExporterMetricsEndpointV1(opts);
+      endpoint.registerExpress(expressApp);
+      endpoints.push(endpoint);
+    }
     return endpoints;
   }
 
@@ -365,6 +400,7 @@ export class PluginLedgerConnectorBesu
       this.log.debug(`${fnTag} Web3 sendSignedTransaction failed`, receipt);
       throw receipt;
     } else {
+      this.prometheusExporter.addCurrentTransaction();
       return { transactionReceipt: receipt };
     }
   }

packages/cactus-plugin-ledger-connector-besu/src/main/typescript/prometheus-exporter/data-fetcher.ts

@@ -0,0 +1,8 @@
+import { Transactions } from "./response.type";
+
+import { totalTxCount, K_CACTUS_BESU_TOTAL_TX_COUNT } from "./metrics";
+
+export async function collectMetrics(transactions: Transactions) {
+  transactions.counter++;
+  totalTxCount.labels(K_CACTUS_BESU_TOTAL_TX_COUNT).set(transactions.counter);
+}

packages/cactus-plugin-ledger-connector-besu/src/main/typescript/prometheus-exporter/metrics.ts

@@ -0,0 +1,9 @@
+import { Gauge } from "prom-client";
+
+export const K_CACTUS_BESU_TOTAL_TX_COUNT = "cactus_besu_total_tx_count";
+
+export const totalTxCount = new Gauge({
+  name: "cactus_besu_total_tx_count",
+  help: "Total transactions executed",
+  labelNames: ["type"],
+});