Add bridge_app_version metric

changelog.d/362.feature

@@ -0,0 +1 @@
+Add `bridge_app_version` metric, and utility functions to get the bridge app version.

package.json

@@ -40,7 +40,7 @@
     "nedb": "^1.8.0",
     "nopt": "^5.0.0",
     "p-queue": "^6.6.2",
-    "prom-client": "^13.1.0",
+    "prom-client": "^14.0.0",
     "winston": "^3.3.3",
     "winston-daily-rotate-file": "^4.5.1"
   },
@@ -59,7 +59,7 @@
     "nyc": "^15.1.0",
     "ts-node": "^10.2.1",
     "typedoc": "^0.20.36",
-    "typescript": "^4.2.3",
+    "typescript": "^4.4.3",
     "winston-transport": "^4.4.0"
   }
 }

src/bridge.ts

@@ -1571,6 +1571,10 @@ export class Bridge {
      * serve the "/metrics" page in the usual way.
      * The instance will automatically register the Matrix SDK metrics by calling
      * {PrometheusMetrics~registerMatrixSdkMetrics}.
+     *
+     * Ensure that `PackageInfo.getBridgeVersion` is returns the correct version before calling this,
+     * as changes to the bridge version after metric instantiation will not be detected.
+     *
      * @param {boolean} registerEndpoint Register the /metrics endpoint on the appservice HTTP server. Defaults to true.
      *                                   Note: `listen()` must have been called if this is true or this will throw.
      * @param {Registry?} registry Optionally provide an alternative registry for metrics.

src/components/app-service-bot.ts

@@ -17,7 +17,7 @@ limitations under the License.
 import { AppServiceRegistration } from "matrix-appservice";
 import { MembershipCache, UserProfile } from "./membership-cache";
 import { StateLookupEvent } from "..";
-import { MatrixClient, MatrixProfileInfo } from "matrix-bot-sdk";
+import { MatrixClient } from "matrix-bot-sdk";
 
 /**
  * Construct an AS bot user which has various helper methods.

src/components/prometheusmetrics.ts

@@ -19,7 +19,8 @@ import { Request, Response } from "express";
 import { Bridge } from "..";
 import Logger from "./logging";
 import { Appservice as BotSdkAppservice, FunctionCallContext, METRIC_MATRIX_CLIENT_FAILED_FUNCTION_CALL,
-    METRIC_MATRIX_CLIENT_FUNCTION_CALL, METRIC_MATRIX_CLIENT_SUCCESSFUL_FUNCTION_CALL } from "matrix-bot-sdk";
+    METRIC_MATRIX_CLIENT_SUCCESSFUL_FUNCTION_CALL } from "matrix-bot-sdk";
+import { getBridgeVersion } from "../utils/package-info";
 type CollectorFunction = () => Promise<void>|void;
 
 export interface BridgeGaugesCounts {
@@ -111,8 +112,20 @@ export class PrometheusMetrics {
     private counters: {[name: string]: PromClient.Counter<string>} = {};
     private collectors: CollectorFunction[] = [];
     private register: Registry;
+    /**
+     * Constructs a new Prometheus Metrics instance.
+     * The metric `app_version` will be set here, so ensure that `getBridgeVersion`
+     * will return the correct bridge version.
+     * @param register A custom registry to provide, if not using the global default.
+     */
     constructor(register?: Registry) {
         this.register = register || PromClient.register;
+        this.addCounter({
+            name: "app_version",
+            help: "Version number of the bridge",
+            labels: ["version"],
+        });
+        this.counters["app_version"].inc({ version: getBridgeVersion()});
         PromClient.collectDefaultMetrics({ register: this.register });
     }
 

src/index.ts

@@ -58,6 +58,8 @@ export * from "./components/bridge-info-state";
 export * from "./components/user-activity";
 export * from "./components/bridge-blocker";
 
+export * from "./utils/package-info";
+
 export { AppServiceRegistration, AppService, AppServiceOutput } from "matrix-appservice";
 
 

src/utils/package-info.ts

@@ -0,0 +1,33 @@
+import { join, resolve } from "path";
+let BridgeVersion: string;
+
+/**
+ * Forcibly set the version of the bridge, for use by other components.
+ * This will override `getBridgeVersion`s default behaviour of fetching the
+ * version from package.json.
+ * @param version A version string e.g. `v1.0.0`
+ */
+export function setBridgeVersion(version: string): void {
+    BridgeVersion = version;
+}
+
+/**
+ * Get the current version of the bridge from the package.json file.
+ * @param packageJsonPath The path to the package.json of the bridge.
+ * @returns Either the version number, or unknown.
+ */
+export function getBridgeVersion(packageJsonPath = "./package.json"): string {
+    if (BridgeVersion) {
+        return BridgeVersion;
+    }
+    packageJsonPath = join(resolve(packageJsonPath));
+    try {
+        // eslint-disable-next-line @typescript-eslint/no-var-requires
+        const nodePackage = require(packageJsonPath);
+        BridgeVersion = nodePackage.version;
+    }
+    catch (err) {
+        BridgeVersion = "unknown";
+    }
+    return BridgeVersion;
+}

tsconfig.json

@@ -12,6 +12,8 @@
     "strict": true,
     "esModuleInterop": true,
     "strictNullChecks": true,
+    /* We don't support this yet */
+    "useUnknownInCatchVariables": false,
     "skipLibCheck": true, /* matrix-js-sdk throws up errors */
   },
   "include": [

yarn.lock

@@ -2906,10 +2906,10 @@ progress@^2.0.0, progress@^2.0.3:
   resolved "https://registry.yarnpkg.com/progress/-/progress-2.0.3.tgz#7e8cf8d8f5b8f239c1bc68beb4eb78567d572ef8"
   integrity sha512-7PiHtLll5LdnKIMw100I+8xJXR5gW2QwWYkT6iJva0bXitZKa/XMrSbdmg3r2Xnaidz9Qumd0VPaMrZlF9V9sA==
 
-prom-client@^13.1.0:
-  version "13.1.0"
-  resolved "https://registry.yarnpkg.com/prom-client/-/prom-client-13.1.0.tgz#1185caffd8691e28d32e373972e662964e3dba45"
-  integrity sha512-jT9VccZCWrJWXdyEtQddCDszYsiuWj5T0ekrPszi/WEegj3IZy6Mm09iOOVM86A4IKMWq8hZkT2dD9MaSe+sng==
+prom-client@^14.0.0:
+  version "14.0.0"
+  resolved "https://registry.yarnpkg.com/prom-client/-/prom-client-14.0.0.tgz#7af5a0f8f544743f0dee4447c06ac9bb0d052719"
+  integrity sha512-etPa4SMO4j6qTn2uaSZy7+uahGK0kXUZwO7WhoDpTf3yZ837I3jqUDYmG6N0caxuU6cyqrg0xmOxh+yneczvyA==
   dependencies:
     tdigest "^0.1.1"
 
@@ -3646,10 +3646,10 @@ typedoc@^0.20.36:
     shiki "^0.9.3"
     typedoc-default-themes "^0.12.10"
 
-typescript@^4.2.3:
-  version "4.2.4"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.2.4.tgz#8610b59747de028fda898a8aef0e103f156d0961"
-  integrity sha512-V+evlYHZnQkaz8TRBuxTA92yZBPotr5H+WhQ7bD3hZUndx5tGOa1fuCgeSjxAzM1RiN5IzvadIXTVefuuwZCRg==
+typescript@^4.4.3:
+  version "4.4.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.4.3.tgz#bdc5407caa2b109efd4f82fe130656f977a29324"
+  integrity sha512-4xfscpisVgqqDfPaJo5vkd+Qd/ItkoagnHpufr+i2QCHBsNYp+G7UAoyFl8aPtx879u38wPV65rZ8qbGZijalA==
 
 uglify-js@^3.1.4:
   version "3.13.4"