Recognize IFILE parameter in tnsnames.ora to read multiple custom network cofniguration files

Author: sharadraju

doc/src/release_notes.rst

@@ -13,6 +13,9 @@ node-oracledb `v6.6.0 <https://github.com/oracle/node-oracledb/compare/v6.5.1...
 Thin Mode Changes
 +++++++++++++++++
 
+#) Added support to use IFILE parameter to embed custom
+   network  configuration files in the main tnsnames.ora file.
+
 #) Fixed bug which throws a ``TypeError: objType.attributes is not iterable``
    error when :ref:`DbObject Class <dbobjectclass>` instance contains an
    attribute of type ``SYS.XMLTYPE``.

lib/thin/sqlnet/paramParser.js

@@ -32,6 +32,7 @@ const process = require('process');
 const readline = require('readline');
 const errors = require("../../errors.js");
 
+const MAX_IFILE_DEPTH = 4;
 /**
  * Returns File path of the tnsnames.ora if it exists.
  */
@@ -59,23 +60,42 @@ function tnsnamesFilePath(configDir) {
   }
 }
 
-let prevmtime = 0;
-
 class NLParamParser {
+
+  constructor() {
+    this.waiters = [];
+    this.readInProgress = false;
+  }
   /**
  * Reads the given file line by line and stores the
  * network service names mapped to connect descriptors in the hashtable.
  * @param {string} file_path
  * @returns {Promise}
  */
   async initializeNlpa(file_path) {
-    const stat = fs.statSync(file_path);
-
-    if (!(stat.mtime - prevmtime)) {
-      /* File has been read */
+    if (this.readInProgress) {
+      await new Promise((resolve) => {
+        this.waiters.push(resolve);
+      });
+    }
+    if (!this.checkModfTime()) {
+      /* No File has been modified */
       return this.ht;
     }
+    this.ht = new Map();
+    this.modTime = new Map(); //stores modified time of each IFile
+    this.readInProgress = true;
+    await this.start(file_path, 0); //start with 0 depth (tnsnames.ora)
+    return this.ht;
+  }
+
+  async start(file_path, depth) {
 
+    if (depth > MAX_IFILE_DEPTH)
+      return; //ignore after max depth
+    const stat = fs.statSync(file_path);
+    // store file path and its modified time.
+    this.modTime.set(file_path, stat.mtime);
     // Creating a readable stream from file
     // readline module reads line by line
     // but from a readable stream only.
@@ -84,52 +104,49 @@ class NLParamParser {
       output: process.stdout,
       terminal: false
     });
-    this.ht = new Map();
-
-    const start = async () =>{
-      let nvElem = "";
-      for await (let line of file) {
-        if (line.length == 0) {   // ignore empty lines
-          continue;
-        } else if (line[0] == '#') {  // comment line
+    let nvElem = "";
+    for await (let line of file) {
+      if (line.length == 0) {   // ignore empty lines
+        continue;
+      } else if (line[0] == '#') {  // comment line
+        continue;
+      } else if ((line[0] == ' ') ||    // continued input on new line
+                  (line[0] == '\t') ||
+                  (line[0] == ')') ||
+                  (line[0] == '(')) {
+        line = line.replace(/\s+/g, '');
+        line = this.checkNLPforComments(line);
+        if (line.length == 0)
           continue;
-        } else if ((line[0] == ' ') ||    // continued input on new line
-                    (line[0] == '\t') ||
-                    (line[0] == ')') ||
-                    (line[0] == '(')) {
-          line = line.replace(/\s+/g, '');
-          line = this.checkNLPforComments(line);
-          if (line.length == 0)
-            continue;
-          else {
-            nvElem = nvElem + line;
-          }
+        else {
+          nvElem = nvElem + line;
+        }
 
-        } else {  // new NV Element starting here
-          if (nvElem.length == 0) {
+      } else {  // new NV Element starting here
+        if (nvElem.length == 0) {
 
-            line = this.checkNLPforComments(line);
-            nvElem = nvElem + line;
+          line = this.checkNLPforComments(line);
+          nvElem = nvElem + line;
 
-          } else if (nvElem.length != 0) {
-            this.addNLPListElement(nvElem); // Add Parameter to Hashtable
-            nvElem = ""; // Clear first, before storing current line
+        } else if (nvElem.length != 0) {
+          await this.addNLPListElement(nvElem, depth); // Add Parameter to Hashtable
+          nvElem = ""; // Clear first, before storing current line
 
-            line = this.checkNLPforComments(line);
-            nvElem = nvElem + line;
-          }
+          line = this.checkNLPforComments(line);
+          nvElem = nvElem + line;
         }
       }
-      if (nvElem.length != 0) { // at eof, still one more parameter to read
-        this.addNLPListElement(nvElem);
-        nvElem = "";      // clear nvElem buffer after added
-      }
-      prevmtime = stat.mtime;
-      return this.ht;
-    };
-    return await start();
+    }
+    if (nvElem.length != 0) { // at eof, still one more parameter to read
+      await this.addNLPListElement(nvElem, depth);
+      nvElem = "";      // clear nvElem buffer after added
+    }
+    this.readInProgress = false;
+    let waiter;
+    while ((waiter = this.waiters.pop())) {
+      waiter();
+    }
   }
-
   /**
    * Given a string, this method looks if the '#' character is present.
    * If true, the line is truncated from that point onwards until the end
@@ -155,11 +172,28 @@ class NLParamParser {
     }
     return str1.join('');
   }
+  // check if any of the IFiles has been changed
+  checkModfTime() {
+    if (this.modTime) {
+      for (const [key, value] of this.modTime) {
+        if (fs.existsSync(key)) {
+          const stat = fs.statSync(key);
+          if ((stat.mtime - value > 0)) {
+            return true;
+          }
+        } else
+          return true;
+      }
+    } else {
+      return true;
+    }
+    return false;
+  }
   /**
     * adds name value pairs from the input buffer into the hash table.
     * @param {string} ibuf
     */
-  addNLPListElement(ibuf) {
+  async addNLPListElement(ibuf, depth) {
     const res = ibuf.split(/\r?\n/).filter(element => element);
     for (let i = 0; i < res.length; i++) {
       if (res[i].charAt(0) != '(') {
@@ -169,14 +203,17 @@ class NLParamParser {
       const name = nvp.name;
       const uname = name.toUpperCase();
       nvp.name = uname;
-      const unames = uname.split(","); //multiple aliases (alias1, alias2, alias3)
-      for (let i = 0; i < unames.length; i++) {
-        this.ht.set(unames[i], nvp);
+      // support for ifile
+      if (uname == 'IFILE') {
+        await this.start(nvp.atom, depth + 1);
+      } else {
+        const unames = uname.split(","); //multiple aliases (alias1, alias2, alias3)
+        for (let i = 0; i < unames.length; i++) {
+          this.ht.set(unames[i], nvp);
+        }
       }
     }
   }
-
-
   toString() {
     let out = "";
     this.ht.forEach((value) => {