refactor(session): implemented session state

.vscode/settings.json

@@ -1,5 +1,3 @@
 {
-  "cSpell.words": [
-    "autoexec"
-  ]
+  "cSpell.words": ["autoexec", "initialising"]
 }

api/src/controllers/internal/Execution.ts

@@ -2,7 +2,7 @@ import path from 'path'
 import fs from 'fs'
 import { getSessionController, processProgram } from './'
 import { readFile, fileExists, createFile, readFileBinary } from '@sasjs/utils'
-import { PreProgramVars, Session, TreeNode } from '../../types'
+import { PreProgramVars, Session, TreeNode, SessionState } from '../../types'
 import {
   extractHeaders,
   getFilesFolder,
@@ -75,8 +75,7 @@ export class ExecutionController {
 
     const session =
       sessionByFileUpload ?? (await sessionController.getSession())
-    session.inUse = true
-    session.consumed = true
+    session.state = SessionState.running
 
     const logPath = path.join(session.path, 'log.log')
     const headersPath = path.join(session.path, 'stpsrv_header.txt')
@@ -121,7 +120,7 @@ export class ExecutionController {
       : ''
 
     // it should be deleted by scheduleSessionDestroy
-    session.inUse = false
+    session.state = SessionState.completed
 
     const resultParts = []
 
@@ -145,7 +144,9 @@ export class ExecutionController {
     return {
       httpHeaders,
       result:
-        isDebugOn(vars) || session.crashed ? resultParts.join(`\n`) : webout
+        isDebugOn(vars) || session.failureReason
+          ? resultParts.join(`\n`)
+          : webout
     }
   }
 

api/src/controllers/internal/FileUploadController.ts

@@ -2,11 +2,8 @@ import { Request, RequestHandler } from 'express'
 import multer from 'multer'
 import { uuidv4 } from '@sasjs/utils'
 import { getSessionController } from '.'
-import {
-  executeProgramRawValidation,
-  getRunTimeAndFilePath,
-  RunTimeType
-} from '../../utils'
+import { executeProgramRawValidation, getRunTimeAndFilePath } from '../../utils'
+import { SessionState } from '../../types'
 
 export class FileUploadController {
   private storage = multer.diskStorage({
@@ -56,9 +53,8 @@ export class FileUploadController {
     }
 
     const session = await sessionController.getSession()
-    // marking consumed true, so that it's not available
-    // as readySession for any other request
-    session.consumed = true
+    // change session state to 'running', so that it's not available for any other request
+    session.state = SessionState.running
 
     req.sasjsSession = session
 

api/src/controllers/internal/Session.ts

@@ -1,5 +1,5 @@
 import path from 'path'
-import { Session } from '../../types'
+import { Session, SessionState } from '../../types'
 import { promisify } from 'util'
 import { execFile } from 'child_process'
 import {
@@ -23,7 +23,9 @@ export class SessionController {
   protected sessions: Session[] = []
 
   protected getReadySessions = (): Session[] =>
-    this.sessions.filter((sess: Session) => sess.ready && !sess.consumed)
+    this.sessions.filter(
+      (session: Session) => session.state === SessionState.pending
+    )
 
   protected async createSession(): Promise<Session> {
     const sessionId = generateUniqueFileName(generateTimestamp())
@@ -39,19 +41,18 @@ export class SessionController {
 
     const session: Session = {
       id: sessionId,
-      ready: true,
-      inUse: true,
-      consumed: false,
-      completed: false,
+      state: SessionState.pending,
       creationTimeStamp,
       deathTimeStamp,
       path: sessionFolder
     }
 
     const headersPath = path.join(session.path, 'stpsrv_header.txt')
+
     await createFile(headersPath, 'content-type: text/html; charset=utf-8')
 
     this.sessions.push(session)
+
     return session
   }
 
@@ -83,10 +84,7 @@ export class SASSessionController extends SessionController {
 
     const session: Session = {
       id: sessionId,
-      ready: false,
-      inUse: false,
-      consumed: false,
-      completed: false,
+      state: SessionState.initialising,
       creationTimeStamp,
       deathTimeStamp,
       path: sessionFolder
@@ -144,13 +142,20 @@ ${autoExecContent}`
       process.sasLoc!.endsWith('sas.exe') ? session.path : ''
     ])
       .then(() => {
-        session.completed = true
+        session.state = SessionState.completed
+
         process.logger.info('session completed', session)
       })
       .catch((err) => {
-        session.completed = true
-        session.crashed = err.toString()
-        process.logger.error('session crashed', session.id, session.crashed)
+        session.state = SessionState.failed
+
+        session.failureReason = err.toString()
+
+        process.logger.error(
+          'session crashed',
+          session.id,
+          session.failureReason
+        )
       })
 
     // we have a triggered session - add to array
@@ -167,15 +172,19 @@ ${autoExecContent}`
     const codeFilePath = path.join(session.path, 'code.sas')
 
     // TODO: don't wait forever
-    while ((await fileExists(codeFilePath)) && !session.crashed) {}
+    while (
+      (await fileExists(codeFilePath)) &&
+      session.state !== SessionState.failed
+    ) {}
 
-    if (session.crashed)
+    if (session.state === SessionState.failed) {
       process.logger.error(
         'session crashed! while waiting to be ready',
-        session.crashed
+        session.failureReason
       )
-
-    session.ready = true
+    } else {
+      session.state = SessionState.pending
+    }
   }
 
   private async deleteSession(session: Session) {
@@ -189,37 +198,33 @@ ${autoExecContent}`
   }
 
   private scheduleSessionDestroy(session: Session) {
-    setTimeout(
-      async () => {
-        if (session.inUse) {
-          // adding 10 more minutes
+    setTimeout(async () => {
+      if (session.state === SessionState.running) {
+        // adding 10 more minutes
+        const newDeathTimeStamp =
+          parseInt(session.deathTimeStamp) + 10 * 60 * 1000
+        session.deathTimeStamp = newDeathTimeStamp.toString()
+
+        this.scheduleSessionDestroy(session)
+      } else {
+        const { expiresAfterMins } = session
+
+        // delay session destroy if expiresAfterMins present
+        if (expiresAfterMins && session.state !== SessionState.completed) {
+          // calculate session death time using expiresAfterMins
           const newDeathTimeStamp =
-            parseInt(session.deathTimeStamp) + 10 * 60 * 1000
+            parseInt(session.deathTimeStamp) + expiresAfterMins.mins * 60 * 1000
           session.deathTimeStamp = newDeathTimeStamp.toString()
 
+          // set expiresAfterMins to true to avoid using it again
+          session.expiresAfterMins!.used = true
+
           this.scheduleSessionDestroy(session)
         } else {
-          const { expiresAfterMins } = session
-
-          // delay session destroy if expiresAfterMins present
-          if (expiresAfterMins && !expiresAfterMins.used) {
-            // calculate session death time using expiresAfterMins
-            const newDeathTimeStamp =
-              parseInt(session.deathTimeStamp) +
-              expiresAfterMins.mins * 60 * 1000
-            session.deathTimeStamp = newDeathTimeStamp.toString()
-
-            // set expiresAfterMins to true to avoid using it again
-            session.expiresAfterMins!.used = true
-
-            this.scheduleSessionDestroy(session)
-          } else {
-            await this.deleteSession(session)
-          }
+          await this.deleteSession(session)
         }
-      },
-      parseInt(session.deathTimeStamp) - new Date().getTime() - 100
-    )
+      }
+    }, parseInt(session.deathTimeStamp) - new Date().getTime() - 100)
   }
 }
 

api/src/controllers/internal/processProgram.ts

@@ -3,7 +3,7 @@ import { WriteStream, createWriteStream } from 'fs'
 import { execFile } from 'child_process'
 import { once } from 'stream'
 import { createFile, moveFile } from '@sasjs/utils'
-import { PreProgramVars, Session } from '../../types'
+import { PreProgramVars, Session, SessionState } from '../../types'
 import { RunTimeType } from '../../utils'
 import {
   ExecutionVars,
@@ -49,7 +49,7 @@ export const processProgram = async (
     await moveFile(codePath + '.bkp', codePath)
 
     // we now need to poll the session status
-    while (!session.completed) {
+    while (session.state === SessionState.completed) {
       await delay(50)
     }
   } else {
@@ -114,13 +114,20 @@ export const processProgram = async (
 
     await execFilePromise(executablePath, [codePath], writeStream)
       .then(() => {
-        session.completed = true
+        session.state = SessionState.completed
+
         process.logger.info('session completed', session)
       })
       .catch((err) => {
-        session.completed = true
-        session.crashed = err.toString()
-        process.logger.error('session crashed', session.id, session.crashed)
+        session.state = SessionState.failed
+
+        session.failureReason = err.toString()
+
+        process.logger.error(
+          'session crashed',
+          session.id,
+          session.failureReason
+        )
       })
 
     // copy the code file to log and end write stream

api/src/routes/api/spec/stp.spec.ts

@@ -25,7 +25,7 @@ import {
   SASSessionController
 } from '../../../controllers/internal'
 import * as ProcessProgramModule from '../../../controllers/internal/processProgram'
-import { Session } from '../../../types'
+import { Session, SessionState } from '../../../types'
 
 const clientId = 'someclientID'
 
@@ -493,10 +493,7 @@ const mockedGetSession = async () => {
 
   const session: Session = {
     id: sessionId,
-    ready: true,
-    inUse: true,
-    consumed: false,
-    completed: false,
+    state: SessionState.pending,
     creationTimeStamp,
     deathTimeStamp,
     path: sessionFolder

api/src/types/Session.ts

@@ -1,12 +1,16 @@
+export enum SessionState {
+  initialising = 'initialising', // session is initialising and nor ready to be used yet
+  pending = 'pending', // session is ready to be used
+  running = 'running', // session is in use
+  completed = 'completed', // session is completed and can be destroyed
+  failed = 'failed' // session failed
+}
 export interface Session {
   id: string
-  ready: boolean
+  state: SessionState
   creationTimeStamp: string
   deathTimeStamp: string
   path: string
-  inUse: boolean
-  consumed: boolean
-  completed: boolean
-  crashed?: string
   expiresAfterMins?: { mins: number; used: boolean }
+  failureReason?: string
 }