fix(session): add internal SAS error handler

src/SessionManager.ts

@@ -2,6 +2,12 @@ import { Session, Context, CsrfToken } from './types'
 import { asyncForEach, makeRequest, isUrl } from './utils'
 
 const MAX_SESSION_COUNT = 1
+const RETRY_LIMIT: number = 3
+let RETRY_COUNT: number = 0
+const INTERNAL_SAS_ERROR = {
+  status: 304,
+  message: 'Not Modified'
+}
 
 export class SessionManager {
   constructor(
@@ -27,19 +33,22 @@ export class SessionManager {
 
   async getSession(accessToken?: string) {
     await this.createSessions(accessToken)
-    this.createAndWaitForSession(accessToken)
+    await this.createAndWaitForSession(accessToken)
     const session = this.sessions.pop()
     const secondsSinceSessionCreation =
       (new Date().getTime() - new Date(session!.creationTimeStamp).getTime()) /
       1000
+
     if (
       !session!.attributes ||
       secondsSinceSessionCreation >= session!.attributes.sessionInactiveTimeout
     ) {
       await this.createSessions(accessToken)
       const freshSession = this.sessions.pop()
+
       return freshSession
     }
+
     return session
   }
 
@@ -48,22 +57,37 @@ export class SessionManager {
       method: 'DELETE',
       headers: this.getHeaders(accessToken)
     }
+
     return await this.request<Session>(
       `${this.serverUrl}/compute/sessions/${id}`,
       deleteSessionRequest
-    ).then(() => {
-      this.sessions = this.sessions.filter((s) => s.id !== id)
-    })
+    )
+      .then(() => {
+        this.sessions = this.sessions.filter((s) => s.id !== id)
+      })
+      .catch((err) => {
+        throw err
+      })
   }
 
   private async createSessions(accessToken?: string) {
     if (!this.sessions.length) {
       if (!this.currentContext) {
-        await this.setCurrentContext(accessToken)
+        await this.setCurrentContext(accessToken).catch((err) => {
+          throw err
+        })
       }
+
       await asyncForEach(new Array(MAX_SESSION_COUNT), async () => {
-        const createdSession = await this.createAndWaitForSession(accessToken)
+        const createdSession = await this.createAndWaitForSession(
+          accessToken
+        ).catch((err) => {
+          throw err
+        })
+
         this.sessions.push(createdSession)
+      }).catch((err) => {
+        throw err
       })
     }
   }
@@ -73,13 +97,18 @@ export class SessionManager {
       method: 'POST',
       headers: this.getHeaders(accessToken)
     }
+
     const { result: createdSession, etag } = await this.request<Session>(
       `${this.serverUrl}/compute/contexts/${this.currentContext!.id}/sessions`,
       createSessionRequest
-    )
+    ).catch((err) => {
+      throw err
+    })
 
     await this.waitForSession(createdSession, etag, accessToken)
+
     this.sessions.push(createdSession)
+
     return createdSession
   }
 
@@ -89,6 +118,8 @@ export class SessionManager {
         items: Context[]
       }>(`${this.serverUrl}/compute/contexts?limit=10000`, {
         headers: this.getHeaders(accessToken)
+      }).catch((err) => {
+        throw err
       })
 
       const contextsList =
@@ -107,6 +138,8 @@ export class SessionManager {
       }
 
       this.currentContext = currentContext
+
+      Promise.resolve()
     }
   }
 
@@ -114,6 +147,7 @@ export class SessionManager {
     const headers: any = {
       'Content-Type': 'application/json'
     }
+
     if (accessToken) {
       headers.Authorization = `Bearer ${accessToken}`
     }
@@ -132,24 +166,41 @@ export class SessionManager {
       'If-None-Match': etag
     }
     const stateLink = session.links.find((l: any) => l.rel === 'state')
+
     return new Promise(async (resolve, _) => {
       if (sessionState === 'pending') {
         if (stateLink) {
           if (this.debug) {
             console.log('Polling session status... \n') // ?
           }
-          const { result: state } = await this.request<string>(
+
+          const { result: state } = await this.requestSessionStatus<string>(
             `${this.serverUrl}${stateLink.href}?wait=30`,
             {
               headers
             },
             'text'
-          )
+          ).catch((err) => {
+            throw err
+          })
 
           sessionState = state.trim()
+
           if (this.debug) {
             console.log(`Current state is '${sessionState}'\n`)
           }
+
+          // There is an internal error present in SAS Viya 3.5
+          // Retry to wait for a session status in such case of SAS internal error
+          if (
+            sessionState === INTERNAL_SAS_ERROR.message &&
+            RETRY_COUNT < RETRY_LIMIT
+          ) {
+            RETRY_COUNT++
+
+            resolve(this.waitForSession(session, etag, accessToken))
+          }
+
           resolve(sessionState)
         }
       } else {
@@ -169,6 +220,7 @@ export class SessionManager {
         [this.csrfToken.headerName]: this.csrfToken.value
       }
     }
+
     return await makeRequest<T>(
       url,
       options,
@@ -177,6 +229,36 @@ export class SessionManager {
         this.setCsrfToken(token)
       },
       contentType
-    )
+    ).catch((err) => {
+      throw err
+    })
+  }
+
+  private async requestSessionStatus<T>(
+    url: string,
+    options: RequestInit,
+    contentType: 'text' | 'json' = 'json'
+  ) {
+    if (this.csrfToken) {
+      options.headers = {
+        ...options.headers,
+        [this.csrfToken.headerName]: this.csrfToken.value
+      }
+    }
+
+    return await makeRequest<T>(
+      url,
+      options,
+      (token) => {
+        this.csrfToken = token
+        this.setCsrfToken(token)
+      },
+      contentType
+    ).catch((err) => {
+      if (err.status === INTERNAL_SAS_ERROR.status)
+        return { result: INTERNAL_SAS_ERROR.message }
+
+      throw err
+    })
   }
 }