Client library for access to RRD archive files

1 files changed, 310 insertions, 0 deletions

diff --git a/src/lib/rrdFile.js b/src/lib/rrdFile.js
new file mode 100644
index 0000000..0d8182f
--- /dev/null
+++ b/src/lib/rrdFile.js
@@ -0,0 +1,310 @@
+/*

+ * Client library for access to RRD archive files

+ * Part of the javascriptRRD package

+ * Copyright (c) 2009 Frank Wuerthwein, fkw@ucsd.edu

+ *

+ * Original repository: http://javascriptrrd.sourceforge.net/

+ * 

+ * MIT License [http://www.opensource.org/licenses/mit-license.php]

+ *

+ */

+

+/*

+ *

+ * RRDTool has been developed and is maintained by

+ * Tobias Oether [http://oss.oetiker.ch/rrdtool/]

+ *

+ * This software can be used to read files produced by the RRDTool

+ * but has been developed independently.

+ * 

+ * Limitations:

+ *

+ * This version of the module assumes RRD files created on linux 

+ * with intel architecture and supports both 32 and 64 bit CPUs.

+ * All integers in RRD files are suppoes to fit in 32bit values.

+ *

+ * Only versions 3 and 4 of the RRD archive are supported.

+ *

+ */

+

+/*

+ * Dependencies:

+ *   

+ * The data provided to this module require an object of a class

+ * that implements the following methods:

+ *   getByteAt(idx)            - Return a 8 bit unsigned integer at offset idx

+ *   getShortAt(idx)           - Return a 16 bit unsigned integer at offset idx

+ *   getLongAt(idx)            - Return a 32 bit unsigned integer at offset idx

+ *   getDoubleAt(idx)          - Return a double float at offset idx

+ *   getFastDoubleAt(idx)      - Similar to getDoubleAt but with less precision

+ *   getCStringAt(idx,maxsize) - Return a string of at most maxsize characters

+ *                               that was 0-terminated in the source

+ *

+ * The BinaryFile from binaryXHR.js implements this interface.

+ *

+ */

+

+

+// ============================================================

+// Exception class

+function InvalidRRD(msg) {

+  this.message=msg;

+  this.name="Invalid RRD";

+}

+

+// pretty print

+InvalidRRD.prototype.toString = function() {

+  return this.name + ': "' + this.message + '"';

+}

+

+

+// ============================================================

+// RRD DS handling class

+function RRDDS(rrd_data,rrd_data_idx) {

+  this.rrd_data=rrd_data;

+  this.rrd_data_idx=rrd_data_idx;

+}

+

+RRDDS.prototype.getName = function() {

+  return this.rrd_data.getCStringAt(this.rrd_data_idx,20);

+}

+RRDDS.prototype.getType = function() {

+  return this.rrd_data.getCStringAt(this.rrd_data_idx+20,20);

+}

+RRDDS.prototype.getMin = function() {

+  return this.rrd_data.getDoubleAt(this.rrd_data_idx+48);

+}

+RRDDS.prototype.getMax = function() {

+  return this.rrd_data.getDoubleAt(this.rrd_data_idx+56);

+}

+

+

+// ============================================================

+// RRD RRA handling class

+function RRDRRA(rrd_data,rrd_align,

+		rra_def_idx,rra_ptr_idx,

+		header_size,row_cnt,prev_row_cnts,ds_cnt,pdp_step) {

+  var row_size=ds_cnt*8;

+  var base_rrd_db_idx=header_size+prev_row_cnts*row_size;

+  // get imediately, since it will be needed often

+  var cur_row=rrd_data.getLongAt(rra_ptr_idx);

+

+  var calc_idx = function(row_idx,ds_idx) {

+    if ((row_idx>=0) && (row_idx<row_cnt)) {

+      if ((ds_idx>=0) && (ds_idx<ds_cnt)){

+	// it is round robin, starting from cur_row+1

+	var real_row_idx=row_idx+cur_row+1;

+	if (real_row_idx>=row_cnt) real_row_idx-=row_cnt;

+	return row_size*real_row_idx+ds_idx*8;

+      } else {

+	throw RangeError("DS idx ("+ row_idx +") out of range [0-" + ds_cnt +").");

+      }

+    } else {

+      throw RangeError("Row idx ("+ row_idx +") out of range [0-" + row_cnt +").");

+    }	

+  }

+

+  // ----------------------------

+  // Start of public methods

+

+  this.getName = function() {

+    return rrd_data.getCStringAt(rra_def_idx,20);

+  }

+  this.getPdpPerRow = function() {

+    if (rrd_align==32)

+      return rrd_data.getLongAt(rra_def_idx+24,20);

+    else

+      return rrd_data.getLongAt(rra_def_idx+32,20);

+  }

+  this.getSecsPerRow = function() {

+    return pdp_step*this.getPdpPerRow();

+  }

+

+  this.getNrRows = function() {

+    return row_cnt;

+  }

+  this.getNrDSs = function() {

+    return ds_cnt;

+  }

+

+  this.getEl = function(row_idx,ds_idx) {

+    return rrd_data.getDoubleAt(base_rrd_db_idx+calc_idx(row_idx,ds_idx));

+  }

+  // Extracts only 4 bytes out of 8 in double, loosing in precision (20 bit mantissa)

+  this.getElFast = function(row_idx,ds_idx) {

+    return rrd_data.getFastDoubleAt(base_rrd_db_idx+calc_idx(row_idx,ds_idx));

+  }

+}

+

+// ============================================================

+// RRD Header handling class

+function RRDHeader(rrd_data) {

+  this.rrd_data=rrd_data;

+  this.validate_rrd();

+  this.load_header();

+  this.calc_idxs();

+}

+

+// Internal, used for initialization

+RRDHeader.prototype.validate_rrd = function() {

+  if (this.rrd_data.getCStringAt(0,4)!=="RRD") throw new InvalidRRD("Wrong magic id.");

+

+  this.rrd_version=this.rrd_data.getCStringAt(4,5);

+  if ((this.rrd_version!=="0003")&&(this.rrd_version!=="0004")) {

+    throw new InvalidRRD("Unsupported RRD version "+this.rrd_version+".");

+  }

+

+  if (this.rrd_data.getDoubleAt(12)==8.642135e+130) {

+    this.rrd_align=32;

+  } else if (this.rrd_data.getDoubleAt(16)==8.642135e+130) {

+    this.rrd_align=64;

+  } else {

+    throw new InvalidRRD("Unsupported platform.");

+  }

+}

+

+// Internal, used for initialization

+RRDHeader.prototype.load_header = function() {

+  if (this.rrd_align==32) {

+    this.ds_cnt=this.rrd_data.getLongAt(20,false);

+    this.rra_cnt=this.rrd_data.getLongAt(24,false);

+    this.pdp_step=this.rrd_data.getLongAt(28,false);

+    // 8*10 unused values follow

+    this.top_header_size=112;

+  } else {

+    //get only the low 32 bits, the high 32 should always be 0

+    this.ds_cnt=this.rrd_data.getLongAt(24,false);

+    this.rra_cnt=this.rrd_data.getLongAt(32,false);

+    this.pdp_step=this.rrd_data.getLongAt(40,false);

+    // 8*10 unused values follow

+    this.top_header_size=128;

+  }

+}

+

+// Internal, used for initialization

+RRDHeader.prototype.calc_idxs = function() {

+  this.ds_def_idx=this.top_header_size;

+  // char ds_nam[20], char dst[20], unival par[10]

+  this.ds_el_size=120;

+

+  this.rra_def_idx=this.ds_def_idx+this.ds_el_size*this.ds_cnt;

+  // char cf_nam[20], uint row_cnt, uint pdp_cnt, unival par[10]

+  this.row_cnt_idx;

+  if (this.rrd_align==32) {

+    this.rra_def_el_size=108;

+    this.row_cnt_idx=20;

+  } else {

+    this.rra_def_el_size=120;

+    this.row_cnt_idx=24;

+  }

+

+  this.live_head_idx=this.rra_def_idx+this.rra_def_el_size*this.rra_cnt;

+  // time_t last_up, int last_up_usec

+  if (this.rrd_align==32) {

+    this.live_head_size=8;

+  } else {

+    this.live_head_size=16;

+  }

+

+  this.pdp_prep_idx=this.live_head_idx+this.live_head_size;

+  // char last_ds[30], unival scratch[10]

+  this.pdp_prep_el_size=112;

+

+  this.cdp_prep_idx=this.pdp_prep_idx+this.pdp_prep_el_size*this.ds_cnt;

+  // unival scratch[10]

+  this.cdp_prep_el_size=80;

+

+  this.rra_ptr_idx=this.cdp_prep_idx+this.cdp_prep_el_size*this.ds_cnt*this.rra_cnt;

+  // uint cur_row

+  if (this.rrd_align==32) {

+    this.rra_ptr_el_size=4;

+  } else {

+    this.rra_ptr_el_size=8;

+  }

+  

+  this.header_size=this.rra_ptr_idx+this.rra_ptr_el_size*this.rra_cnt;

+}

+

+// Optional initialization

+// Read and calculate row counts

+RRDHeader.prototype.load_row_cnts = function() {

+  this.rra_def_row_cnts=[];

+  this.rra_def_row_cnt_sums=[]; // how many rows before me

+  for (var i=0; i<this.rra_cnt; i++) {

+    this.rra_def_row_cnts[i]=this.rrd_data.getLongAt(this.rra_def_idx+i*this.rra_def_el_size+this.row_cnt_idx,false);

+    if (i==0) {

+      this.rra_def_row_cnt_sums[i]=0;

+    } else {

+      this.rra_def_row_cnt_sums[i]=this.rra_def_row_cnt_sums[i-1]+this.rra_def_row_cnts[i-1];

+    }

+  }

+}

+

+// ---------------------------

+// Start of user functions

+

+RRDHeader.prototype.getStep = function() {

+  return this.pdp_step;

+}

+RRDHeader.prototype.getLastUpdate = function() {

+  return this.rrd_data.getLongAt(this.live_head_idx,false);

+}

+

+RRDHeader.prototype.getNrDSs = function() {

+  return this.ds_cnt;

+}

+RRDHeader.prototype.getDS = function(idx) {

+  if ((idx>=0) && (idx<this.ds_cnt)) {

+    return new RRDDS(this.rrd_data,this.ds_def_idx+this.ds_el_size*idx);

+  } else {

+    throw RangeError("DS idx ("+ idx +") out of range [0-" + this.ds_cnt +").");

+  }	

+}

+

+// ============================================================

+// RRDFile class

+//   Given a BinaryFile, gives access to the RRD archive fields

+// 

+// Arguments:

+//   bf must be an object compatible with the BinaryFile interface

+function RRDFile(bf) {

+  var rrd_data=bf

+

+  this.rrd_header=new RRDHeader(rrd_data);

+  this.rrd_header.load_row_cnts();

+

+  // ===================================

+  // Start of user functions

+

+  this.getStep = function() {

+    return this.rrd_header.getStep();

+  }

+  this.getLastUpdate = function() {

+    return this.rrd_header.getLastUpdate();

+  }

+

+  this.getNrDSs = function() {

+    return this.rrd_header.getNrDSs();

+  }

+  this.getDS = function(idx) {

+    return this.rrd_header.getDS(idx);

+  }

+

+  this.getNrRRAs = function() {

+    return this.rrd_header.rra_cnt;

+  }

+

+  this.getRRA = function(idx) {

+    if ((idx>=0) && (idx<this.rrd_header.rra_cnt)) {

+      return new RRDRRA(rrd_data,this.rrd_header.rrd_align,

+			this.rrd_header.rra_def_idx+idx*this.rrd_header.rra_def_el_size,

+			this.rrd_header.rra_ptr_idx+idx*this.rrd_header.rra_ptr_el_size,

+			this.rrd_header.header_size,

+			this.rrd_header.rra_def_row_cnts[idx],this.rrd_header.rra_def_row_cnt_sums[idx],

+			this.rrd_header.ds_cnt,this.rrd_header.pdp_step);

+    } else {

+      throw RangeError("RRA idx ("+ idx +") out of range [0-" + this.rrd_header.rra_cnt +").");

+    }	

+  }

+

+}