feat(chain-follower): add WIP Dgraph client and service

Also implements envalid for process.env handling

packages/chain-follower/package.json

@@ -36,12 +36,20 @@
     "@cardano-ogmios/client": "^4.1.0",
     "@cardanosolutions/json-bigint": "^1.0.0",
     "@emurgo/cip14-js": "^2.0.0",
+    "bunyan": "^1.8.15",
+    "death": "^1.1.0",
+    "dgraph-js": "^21.3.1",
+    "envalid": "^7.2.1",
+    "fs-extra": "^10.0.0",
+    "grpc": "^1.24.11",
     "ts-custom-error": "^3.2.0",
     "ts-log": "^2.2.3"
   },
   "devDependencies": {
     "@cardano-graphql/util-dev": "6.0.0",
+    "@types/google-protobuf": "^3.15.5",
     "@types/node": "^14.0.13",
+    "@types/protobufjs": "^6.0.0",
     "shx": "^0.3.2",
     "typescript": "^3.9.5"
   }

packages/chain-follower/src/ChainFollower.ts

@@ -1,38 +1,24 @@
 import {
   ChainSync,
+  ConnectionConfig,
   createChainSyncClient,
   createInteractionContext,
   Schema
 } from '@cardano-ogmios/client'
 import { errors, RunnableModuleState } from '@cardano-graphql/util'
-import { dummyLogger, Logger } from 'ts-log'
+import { dummyLogger } from 'ts-log'
 
 const MODULE_NAME = 'ChainFollower'
 
-interface Config {
-  cardanoNodeConfigPath: string;
-  db: {
-    database: string;
-    host: string;
-    password: string;
-    port: number;
-    user: string;
-  };
-  ogmios?: {
-    host?: string;
-    port?: number;
-  };
-}
-
 export class ChainFollower {
   private chainSyncClient: ChainSync.ChainSyncClient;
   private state: RunnableModuleState;
 
-  constructor (private logger: Logger = dummyLogger) {
+  constructor (private logger = dummyLogger) {
     this.state = null
   }
 
-  public async initialize (ogmiosConfig: Config['ogmios']) {
+  public async initialize (ogmiosConnection: ConnectionConfig) {
     if (this.state !== null) return
     this.state = 'initializing'
     this.logger.info({ module: MODULE_NAME }, 'Initializing')
@@ -43,7 +29,7 @@ export class ChainFollower {
         this.logger.error({ module: MODULE_NAME, code }, reason)
       },
       {
-        connection: ogmiosConfig,
+        connection: ogmiosConnection,
         interactionType: 'LongRunning'
       }
     )

packages/chain-follower/src/DgraphClient.ts

@@ -0,0 +1,20 @@
+import { dummyLogger } from 'ts-log'
+import dgraph from 'dgraph-js'
+
+export interface DgraphClient {
+  setSchema: (schema: string) => Promise<void>
+}
+
+export const createDgraphClient = (address: string, logger = dummyLogger): DgraphClient => {
+  const clientStub = new dgraph.DgraphClientStub(address)
+  const dgraphClient = new dgraph.DgraphClient(clientStub)
+
+  return {
+    async setSchema (schema) {
+      const op = new dgraph.Operation()
+      op.setSchema(schema)
+      await dgraphClient.alter(op)
+      logger.info('Dgraph schema set')
+    }
+  }
+}

packages/chain-follower/src/config.ts

@@ -0,0 +1,18 @@
+import { LogLevelString } from 'bunyan'
+import { cleanEnv, EnvError, host, makeValidator, port, Spec } from 'envalid'
+
+// Todo: Hoist to util package, dedupe
+// custom validator same as str from envalid but with typed return type
+const str = <T extends string = string> (spec?: Spec<T>) => makeValidator((input: string) => {
+  if (typeof input === 'string') return input as T
+  throw new EnvError(`Not a string: "${input}"`)
+})(spec)
+
+export const getConfig = () => cleanEnv(process.env, {
+  dgraphAddress: host(),
+  loggerMinSeverity: str<LogLevelString>({ choices: ['trace', 'debug', 'info', 'warn', 'error', 'fatal'] }),
+  ogmiosHost: host({ default: undefined }),
+  ogmiosPort: port({ default: undefined })
+})
+
+export type Config = ReturnType<typeof getConfig>

packages/chain-follower/src/index.ts

@@ -1 +1,2 @@
 export * from './ChainFollower'
+export * from './DgraphClient'

packages/chain-follower/src/service.ts

@@ -0,0 +1,35 @@
+import { createDgraphClient } from './DgraphClient'
+import { getConfig } from './config'
+import { Logger } from 'ts-log'
+import { createLogger } from 'bunyan'
+import onDeath from 'death'
+import { ChainFollower } from './ChainFollower'
+import { loadSchema} from './util'
+
+(async () => {
+  const config = getConfig()
+
+  const logger: Logger = createLogger({
+    name: 'chain-follower',
+    level: config.loggerMinSeverity
+  })
+
+  try {
+    const dgraphClient = createDgraphClient(config.dgraphAddress)
+    await dgraphClient.setSchema(await loadSchema())
+
+    const chainFollower = new ChainFollower(logger)
+
+    onDeath(async (signal) => {
+      logger.error({ signal }, 'About to exit the process')
+      await chainFollower.shutdown()
+      process.exit(1)
+    })
+
+    await chainFollower.initialize({ host: config.ogmiosHost, port: config.ogmiosPort })
+    await chainFollower.start(['origin'])
+  } catch (error) {
+    logger.error(error)
+    process.exit(1)
+  }
+})()

packages/chain-follower/src/util.ts

@@ -0,0 +1,3 @@
+import { readFile } from 'fs-extra'
+
+export const loadSchema = async (): Promise<string> => readFile('./schema', 'utf-8')