Add support for caching Slack profile data in production using Memcached

.vscode/launch.json

@@ -24,7 +24,11 @@
                 "${workspaceFolder}/index.js"
             ],
             "env": {
-                "DEBUG": "true"
+                "DEBUG": "true",
+                "KUDOS_BOT_CONFIG": "{'options':{'process_whole_history':true},'slack':{'channel_id':'C8P4F6WTB'},'rules':{'tip_per_kudo_in_usd':0.02,'tip_per_reaction_in_usd':0.001,'reaction_threshold':3},'payments':{'STT':{'network_id':'ropsten','private_key':'0xaaaa','contract_address':'0xc55cF4B03948D7EBc8b9E8BAD92643703811d162'},'SNT':{'network_id':'homestead','private_key':'0xaaaa','contract_address':'0x744d70FDBE2Ba4CF95131626614a1763DF805B9E'}}}",
+                "MEMCACHE_URL": "",
+                "MEMCACHE_USERNAME": "",
+                "MEMCACHE_PASSWORD": ""
             }
         },
         {

lib/slack-profile-cache.js

@@ -9,13 +9,23 @@
 //   PombeirP
 
 const MemCache = require('mem-cache')
-const fs = require('fs')
+const memjs = require('memjs')
 const { WebClient } = require('@slack/client')
 
 const token = process.env.SLACK_USER_TOKEN || ''
-const cachePath = './slack-cache.json'
+const cacheMemcachedKey = 'slack-profile-cache-json'
 var allowLoadFromCache = true
 
+// Environment variables are defined in app.yaml.
+let MEMCACHE_URL = process.env.MEMCACHE_URL || '127.0.0.1:11211'
+if (process.env.USE_GAE_MEMCACHE) {
+  MEMCACHE_URL = `${process.env.GAE_MEMCACHE_HOST}:${process.env.GAE_MEMCACHE_PORT}`
+}
+const mc = memjs.Client.create(MEMCACHE_URL, {
+  username: process.env.MEMCACHE_USERNAME,
+  password: process.env.MEMCACHE_PASSWORD
+})
+
 module.exports = (robot) => new GitHubSlackIdMapper(robot)
 
 class GitHubSlackIdMapper {
@@ -28,6 +38,15 @@ class GitHubSlackIdMapper {
     setInterval(() => internalBuild(this.robot, this.cache), 24 * 60 * 60 * 1000)
   }
 
+  async getSlackUsernameFromSlackId (slackUserId) {
+    await this.buildPromise
+    const profile = this.cache.get(getSlackId2ProfileCacheKeyName(slackUserId))
+    if (profile) {
+      return profile.name
+    }
+    return null
+  }
+
   async getGitHubHandleFromSlackId (slackUserId) {
     await this.buildPromise
     const profile = this.cache.get(getSlackId2ProfileCacheKeyName(slackUserId))
@@ -54,13 +73,13 @@ class GitHubSlackIdMapper {
 async function internalBuild (robot, cache) {
   if (allowLoadFromCache) {
     try {
-      const json = fs.readFileSync(cachePath)
+      const json = await mc.get(cacheMemcachedKey)
-      if (json) {
+      if (json.value) {
-        const cacheFromFile = JSON.parse(json)
+        const cacheFromFile = JSON.parse(json.value)
         for (const kvp of cacheFromFile) {
           cache.set(kvp.k, kvp.v)
         }
-        robot.log.info(`Read Slack user cache from file (${cache.length} entries)`)
+        robot.log.info(`Read Slack user cache from ${MEMCACHE_URL} (${cache.length} entries)`)
         allowLoadFromCache = false
         return
       }
@@ -100,14 +119,14 @@ async function internalBuild (robot, cache) {
           robot.log.warn(`No GitHub ID field found in @${username} (${user.id}) profile!`)
         }
 
-        const gitHubUsername = gitHubFieldId && profile.fields && profile.fields[gitHubFieldId] ? profile.fields[gitHubFieldId].value : null
+        const gitHubUsername = gitHubFieldId && profile.fields && profile.fields[gitHubFieldId] ? profile.fields[gitHubFieldId].value.replace('https://github.com/', '') : null
         if (gitHubUsername) {
           usersContainingGitHubInfo = usersContainingGitHubInfo.concat(username)
         } else {
           usersMissingGitHubInfo = usersMissingGitHubInfo.concat(username)
         }
 
-        const data = { github_handle: gitHubUsername }
+        const data = { name: username, github_handle: gitHubUsername }
 
         robot.log.debug(`@${username} (${user.id}) -> ${JSON.stringify(data)}`)
 
@@ -144,7 +163,15 @@ async function internalBuild (robot, cache) {
     for (const key of cache.keys) {
       c.push({ k: key, v: cache.get(key) })
     }
-    fs.writeFileSync(cachePath, JSON.stringify(c, null, 2))
+
+    if (mc) {
+      try {
+        await mc.set(cacheMemcachedKey, c, {})
+        robot.log.info(`Saved cache to Memcached`)
+      } catch (error) {
+        robot.log.warn(`Error while saving cache to Memcached: ${error}`)
+      }
+    }
   } catch (e) {
     robot.log.error(`Error while populating Slack user ID cache: ${e}`)
   }

package.json

@@ -16,6 +16,7 @@
     "hashset": "0.0.6",
     "jenkins": "^0.20.1",
     "mem-cache": "0.0.5",
+    "memjs": "^1.2.0",
     "probot": "^5.0.0",
     "probot-config": "^0.1.0",
     "probot-gpg-status": "^0.5.4",