feat: implement the logic for running python stored programs

api/src/controllers/internal/Session.ts

@@ -197,9 +197,41 @@ export class JSSessionController extends SessionController {
   }
 }
 
+export class PythonSessionController extends SessionController {
+  protected async createSession(): Promise<Session> {
+    const sessionId = generateUniqueFileName(generateTimestamp())
+    const sessionFolder = path.join(getSessionsFolder(), sessionId)
+
+    const creationTimeStamp = sessionId.split('-').pop() as string
+    // death time of session is 15 mins from creation
+    const deathTimeStamp = (
+      parseInt(creationTimeStamp) +
+      15 * 60 * 1000 -
+      1000
+    ).toString()
+
+    const session: Session = {
+      id: sessionId,
+      ready: true,
+      inUse: true,
+      consumed: false,
+      completed: false,
+      creationTimeStamp,
+      deathTimeStamp,
+      path: sessionFolder
+    }
+
+    const headersPath = path.join(session.path, 'stpsrv_header.txt')
+    await createFile(headersPath, 'Content-type: application/json')
+
+    this.sessions.push(session)
+    return session
+  }
+}
+
 export const getSessionController = (
   runTime: RunTimeType
-): SASSessionController | JSSessionController => {
+): SASSessionController | JSSessionController | PythonSessionController => {
   if (runTime === RunTimeType.SAS) {
     return getSASSessionController()
   }
@@ -208,6 +240,10 @@ export const getSessionController = (
     return getJSSessionController()
   }
 
+  if (runTime === RunTimeType.PY) {
+    return getPythonSessionController()
+  }
+
   throw new Error('No Runtime is configured')
 }
 
@@ -227,6 +263,14 @@ const getJSSessionController = (): JSSessionController => {
   return process.jsSessionController
 }
 
+const getPythonSessionController = (): PythonSessionController => {
+  if (process.pythonSessionController) return process.pythonSessionController
+
+  process.pythonSessionController = new PythonSessionController()
+
+  return process.pythonSessionController
+}
+
 const autoExecContent = `
 data _null_;
   /* remove the dummy SYSIN */

api/src/controllers/internal/createPythonProgram.ts

@@ -0,0 +1,65 @@
+import { isWindows } from '@sasjs/utils'
+import { PreProgramVars, Session } from '../../types'
+import { generateFileUploadPythonCode } from '../../utils'
+import { ExecutionVars } from './'
+
+export const createPythonProgram = async (
+  program: string,
+  preProgramVariables: PreProgramVars,
+  vars: ExecutionVars,
+  session: Session,
+  weboutPath: string,
+  tokenFile: string,
+  otherArgs?: any
+) => {
+  const varStatments = Object.keys(vars).reduce(
+    (computed: string, key: string) => `${computed}${key} = '${vars[key]}';\n`,
+    ''
+  )
+
+  const preProgramVarStatments = `
+_SASJS_SESSION_PATH = '${
+    isWindows() ? session.path.replace(/\\/g, '\\\\') : session.path
+  }';
+_WEBOUT = '${isWindows() ? weboutPath.replace(/\\/g, '\\\\') : weboutPath}'; 
+_SASJS_TOKENFILE = '${
+    isWindows() ? tokenFile.replace(/\\/g, '\\\\') : tokenFile
+  }';
+_SASJS_USERNAME = '${preProgramVariables?.username}';
+_SASJS_USERID = '${preProgramVariables?.userId}';
+_SASJS_DISPLAYNAME = '${preProgramVariables?.displayName}';
+_METAPERSON = _SASJS_DISPLAYNAME;
+_METAUSER = _SASJS_USERNAME;
+SASJSPROCESSMODE = 'Stored Program';
+`
+
+  const requiredModules = `import os`
+
+  program = `
+# runtime vars
+${varStatments}
+
+# dynamic user-provided vars
+${preProgramVarStatments}
+
+# change working directory to  session folder
+os.chdir(_SASJS_SESSION_PATH)
+
+# actual job code
+${program}
+
+`
+  // if no files are uploaded filesNamesMap will be undefined
+  if (otherArgs?.filesNamesMap) {
+    const uploadJSCode = await generateFileUploadPythonCode(
+      otherArgs.filesNamesMap,
+      session.path
+    )
+
+    //If js code for the file is generated it will be appended to the top of jsCode
+    if (uploadJSCode.length > 0) {
+      program = `${uploadJSCode}\n` + program
+    }
+  }
+  return requiredModules + program
+}

api/src/controllers/internal/index.ts

@@ -4,4 +4,5 @@ export * from './Execution'
 export * from './FileUploadController'
 export * from './createSASProgram'
 export * from './createJSProgram'
+export * from './createPythonProgram'
 export * from './processProgram'

api/src/controllers/internal/processProgram.ts

@@ -5,7 +5,12 @@ import { once } from 'stream'
 import { createFile, moveFile } from '@sasjs/utils'
 import { PreProgramVars, Session } from '../../types'
 import { RunTimeType } from '../../utils'
-import { ExecutionVars, createSASProgram, createJSProgram } from './'
+import {
+  ExecutionVars,
+  createSASProgram,
+  createJSProgram,
+  createPythonProgram
+} from './'
 
 export const processProgram = async (
   program: string,
@@ -47,6 +52,42 @@ export const processProgram = async (
       // copy the code.js program to log and end write stream
       writeStream.end(program)
 
+      session.completed = true
+      console.log('session completed', session)
+    } catch (err: any) {
+      session.completed = true
+      session.crashed = err.toString()
+      console.log('session crashed', session.id, session.crashed)
+    }
+  } else if (runTime === RunTimeType.PY) {
+    program = await createPythonProgram(
+      program,
+      preProgramVariables,
+      vars,
+      session,
+      weboutPath,
+      tokenFile,
+      otherArgs
+    )
+
+    const codePath = path.join(session.path, 'code.py')
+
+    try {
+      await createFile(codePath, program)
+
+      // create a stream that will write to console outputs to log file
+      const writeStream = fs.createWriteStream(logPath)
+
+      // waiting for the open event so that we can have underlying file descriptor
+      await once(writeStream, 'open')
+
+      execFileSync(process.pythonLoc!, [codePath], {
+        stdio: ['ignore', writeStream, writeStream]
+      })
+
+      // copy the code.py program to log and end write stream
+      writeStream.end(program)
+
       session.completed = true
       console.log('session completed', session)
     } catch (err: any) {