Explicitly parse configuration variables by type (#1004)

Previously, each configuration value is evaluated in order to parse it.
This patch removes that evaluation in favor of a more option-specific
conversion where string values are parsed as strings, lists as lists, and
so on.

---------

Co-authored-by: Noemi <[email protected]>

.changesets/don-t-evaluate-environment-variable-values-to-read-configuration.md

@@ -0,0 +1,8 @@
+---
+bump: "patch"
+type: "change"
+---
+
+Don’t evaluate environment variable values to read configuration
+
+In previous versions of the Node.js integration, environment variables were evaluated to read their values. This version instead parses them based on their expected values.

src/__tests__/config.test.ts

@@ -127,8 +127,12 @@ describe("Configuration", () => {
   describe("with config in the environment", () => {
     it("loads configuration from the environment", () => {
       process.env["APPSIGNAL_ENABLE_STATSD"] = "true"
+      process.env["APPSIGNAL_ENABLE_HOST_METRICS"] = "false"
+      process.env["APPSIGNAL_DNS_SERVERS"] = "8.8.8.8,8.8.4.4"
       const envOptions = {
-        enableStatsd: true
+        enableStatsd: true,
+        enableHostMetrics: false,
+        dnsServers: ["8.8.8.8", "8.8.4.4"]
       }
       const expectedConfig = {
         ...expectedDefaultConfig,
@@ -143,6 +147,59 @@ describe("Configuration", () => {
       expect(config.sources.initial).toEqual({})
       expect(config.sources.env).toEqual(envOptions)
     })
+
+    describe("with a list as APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS", () => {
+      it("sets disableDefaultInstrumentations to the list", () => {
+        process.env["APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS"] =
+          "@opentelemetry/instrumentation-express,@opentelemetry/instrumentation-fastify,@opentelemetry/instrumentation-fs"
+        const envOptions = {
+          disableDefaultInstrumentations: [
+            "@opentelemetry/instrumentation-express",
+            "@opentelemetry/instrumentation-fastify",
+            "@opentelemetry/instrumentation-fs"
+          ]
+        }
+        const expectedConfig = {
+          ...expectedDefaultConfig,
+          ...envOptions
+        }
+        config = new Configuration({})
+
+        expect(config.data).toEqual(expectedConfig)
+      })
+    })
+
+    describe("with APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS set to true", () => {
+      it("sets disableDefaultInstrumentations to true", () => {
+        process.env["APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS"] = "true"
+        const envOptions = {
+          disableDefaultInstrumentations: true
+        }
+        const expectedConfig = {
+          ...expectedDefaultConfig,
+          ...envOptions
+        }
+        config = new Configuration({})
+
+        expect(config.data).toEqual(expectedConfig)
+      })
+    })
+
+    describe("with APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS set to false", () => {
+      it("sets disableDefaultInstrumentations to false", () => {
+        process.env["APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS"] = "false"
+        const envOptions = {
+          disableDefaultInstrumentations: false
+        }
+        const expectedConfig = {
+          ...expectedDefaultConfig,
+          ...envOptions
+        }
+        config = new Configuration({})
+
+        expect(config.data).toEqual(expectedConfig)
+      })
+    })
   })
 
   describe("logFilePath", () => {

src/config.ts

@@ -5,7 +5,14 @@ import fs from "fs"
 import { VERSION } from "./version"
 import { isWritable } from "./utils"
 import { AppsignalOptions } from "./config/options"
-import { ENV_TO_KEY_MAPPING, PRIVATE_ENV_MAPPING } from "./config/configmap"
+import {
+  ENV_TO_KEY_MAPPING,
+  PRIVATE_ENV_MAPPING,
+  BOOL_KEYS,
+  STRING_KEYS,
+  LIST_KEYS,
+  LIST_OR_BOOL_KEYS
+} from "./config/configmap"
 
 /**
  * The AppSignal configuration object.
@@ -169,16 +176,41 @@ export class Configuration {
   private _loadFromEnvironment(): { [key: string]: any } {
     const conf: { [key: string]: any } = {}
 
-    Object.entries(ENV_TO_KEY_MAPPING).forEach(([k, v]) => {
+    STRING_KEYS.forEach(k => {
       const current = process.env[k]
 
       if (current) {
-        try {
-          // attempt to extract a value from a string
-          conf[v] = eval(current)
-        } catch (e) {
-          conf[v] = current
-        }
+        conf[ENV_TO_KEY_MAPPING[k]] = current
+      }
+    })
+
+    BOOL_KEYS.forEach(k => {
+      const current = process.env[k]
+
+      if (current == "true") {
+        conf[ENV_TO_KEY_MAPPING[k]] = true
+      } else if (current == "false") {
+        conf[ENV_TO_KEY_MAPPING[k]] = false
+      }
+    })
+
+    LIST_KEYS.forEach(k => {
+      const current = process.env[k]
+
+      if (current) {
+        conf[ENV_TO_KEY_MAPPING[k]] = current.split(",")
+      }
+    })
+
+    LIST_OR_BOOL_KEYS.forEach(k => {
+      const current = process.env[k]
+
+      if (current == "true") {
+        conf[ENV_TO_KEY_MAPPING[k]] = true
+      } else if (current == "false") {
+        conf[ENV_TO_KEY_MAPPING[k]] = false
+      } else if (current) {
+        conf[ENV_TO_KEY_MAPPING[k]] = current.split(",")
       }
     })
 

src/config/configmap.ts

@@ -114,3 +114,52 @@ export const JS_TO_RUBY_MAPPING: Record<keyof AppsignalOptions, string> = {
   statsdPort: "statsd_port",
   workingDirectoryPath: "working_directory_path"
 }
+
+export const BOOL_KEYS: string[] = [
+  "APPSIGNAL_ACTIVE",
+  "APPSIGNAL_ENABLE_HOST_METRICS",
+  "APPSIGNAL_ENABLE_OPENTELEMETRY_HTTP",
+  "APPSIGNAL_ENABLE_MINUTELY_PROBES",
+  "APPSIGNAL_ENABLE_STATSD",
+  "APPSIGNAL_ENABLE_NGINX_METRICS",
+  "APPSIGNAL_FILES_WORLD_ACCESSIBLE",
+  "APPSIGNAL_RUNNING_IN_CONTAINER",
+  "APPSIGNAL_SEND_ENVIRONMENT_METADATA",
+  "APPSIGNAL_SEND_PARAMS",
+  "APPSIGNAL_SEND_SESSION_DATA"
+]
+
+export const STRING_KEYS: string[] = [
+  "APPSIGNAL_APP_ENV",
+  "APPSIGNAL_APP_NAME",
+  "APPSIGNAL_BIND_ADDRESS",
+  "APPSIGNAL_CA_FILE_PATH",
+  "APPSIGNAL_HOSTNAME",
+  "APPSIGNAL_HOST_ROLE",
+  "APPSIGNAL_HTTP_PROXY",
+  "APPSIGNAL_INITIALIZE_OPENTELEMETRY_SDK",
+  "APPSIGNAL_LOG",
+  "APPSIGNAL_LOG_LEVEL",
+  "APPSIGNAL_LOG_PATH",
+  "APPSIGNAL_LOGGING_ENDPOINT",
+  "APPSIGNAL_OPENTELEMETRY_PORT",
+  "APPSIGNAL_PUSH_API_ENDPOINT",
+  "APPSIGNAL_PUSH_API_KEY",
+  "APPSIGNAL_STATSD_PORT",
+  "APPSIGNAL_WORKING_DIRECTORY_PATH",
+  "APP_REVISION"
+]
+
+export const LIST_KEYS: string[] = [
+  "APPSIGNAL_DNS_SERVERS",
+  "APPSIGNAL_FILTER_PARAMETERS",
+  "APPSIGNAL_FILTER_SESSION_DATA",
+  "APPSIGNAL_IGNORE_ACTIONS",
+  "APPSIGNAL_IGNORE_ERRORS",
+  "APPSIGNAL_IGNORE_NAMESPACES",
+  "APPSIGNAL_REQUEST_HEADERS"
+]
+
+export const LIST_OR_BOOL_KEYS: string[] = [
+  "APPSIGNAL_DISABLE_DEFAULT_INSTRUMENTATIONS"
+]