org.jrobin.core
public class RrdDb extends Object implements RrdUpdater
Main class used to create and manipulate round robin databases (RRDs). Use this class to perform
update and fetch operations on exisiting RRDs, to create new RRD from
the definition (object of class RrdDef
) or
from XML file (dumped content of RRDTool's or JRobin's RRD file).
Each RRD is backed with some kind of storage. For example, RRDTool supports only one kind of storage (disk file). On the contrary, JRobin gives you freedom to use other storage (backend) types even to create your own backend types for some special purposes. JRobin by default stores RRD data in files (as RRDTool), but you might choose to store RRD data in memory (this is supported in JRobin), to use java.nio.* instead of java.io.* package for file manipulation (also supported) or to store whole RRDs in the SQL database (you'll have to extend some classes to do this).
Note that JRobin uses binary format different from RRDTool's format. You cannot use this class to manipulate RRD files created with RRDTool. However, if you perform the same sequence of create, update and fetch operations, you will get exactly the same results from JRobin and RRDTool.
You will not be able to use JRobin API if you are not familiar with basic RRDTool concepts. Good place to start is the official RRD tutorial and relevant RRDTool man pages: rrdcreate, rrdupdate, rrdfetch and rrdgraph. For RRDTool's advanced graphing capabilities (RPN extensions), also supported in JRobin, there is an excellent CDEF tutorial.
See Also: RrdBackend RrdBackendFactory
Field Summary | |
---|---|
static String | PREFIX_RRDTool
prefix to identify external RRDTool file source used in various RrdDb constructors |
static String | PREFIX_XML
prefix to identify external XML file source used in various RrdDb constructors |
Constructor Summary | |
---|---|
RrdDb(RrdDef rrdDef) Constructor used to create new RRD object from the definition. | |
RrdDb(RrdDef rrdDef, RrdBackendFactory factory) Constructor used to create new RRD object from the definition object but with a storage (backend) different from default. JRobin uses factories to create RRD backend objecs. | |
RrdDb(String path, boolean readOnly) Constructor used to open already existing RRD. | |
RrdDb(String path, boolean readOnly, RrdBackendFactory factory) Constructor used to open already existing RRD backed with a storage (backend) different from default. | |
RrdDb(String path) Constructor used to open already existing RRD in R/W mode, with a default storage (backend) type (file on the disk). | |
RrdDb(String path, RrdBackendFactory factory) Constructor used to open already existing RRD in R/W mode with a storage (backend) type different from default. | |
RrdDb(String rrdPath, String externalPath) Constructor used to create RRD files from external file sources. | |
RrdDb(String rrdPath, String externalPath, RrdBackendFactory factory) Constructor used to create RRD files from external file sources with a backend type different from default. |
Method Summary | |
---|---|
void | close()
Closes RRD. |
boolean | containsDs(String dsName)
Checks presence of a specific datasource.
|
void | copyStateTo(RrdUpdater other)
Copies object's internal state to another RrdDb object.
|
FetchRequest | createFetchRequest(String consolFun, long fetchStart, long fetchEnd, long resolution) Prepares fetch request to be executed on this RRD. |
FetchRequest | createFetchRequest(String consolFun, long fetchStart, long fetchEnd) Prepares fetch request to be executed on this RRD. |
Sample | createSample(long time) Creates new sample with the given timestamp and all datasource values set to 'unknown'. |
Sample | createSample() Creates new sample with the current timestamp and all data source values set to 'unknown'. |
String | dump() Returns string representing complete internal RRD state. |
void | dumpXml(OutputStream destination) Writes the RRD content to OutputStream using XML format. |
void | dumpXml(String filename) Dumps internal RRD state to XML file. |
void | exportXml(OutputStream destination)
This method is just an alias for dumpXml method.
|
String | exportXml()
This method is just an alias for getXml method.
|
void | exportXml(String filename)
This method is just an alias for dumpXml(String) method.
|
protected void | finalize() |
Archive | findMatchingArchive(FetchRequest request) |
Archive | findStartMatchArchive(String consolFun, long startTime, long resolution)
Finds the archive that best matches to the start time (time period being start-time until now)
and requested resolution.
|
int | getArcCount()
Returns the number of RRA arcihves defined in the file
|
Archive | getArchive(int arcIndex)
Returns Archive object for the given archive index.
|
Archive | getArchive(String consolFun, int steps)
Returns Archive object with the given consolidation function and the number
of steps.
|
int | getArcIndex(String consolFun, int steps)
Returns index of Archive object with the given consolidation function and the number
of steps. |
byte[] | getBytes()
Returns an array of bytes representing the whole RRD.
|
String | getCanonicalPath()
Returns canonical path to the underlying RRD file. |
Datasource | getDatasource(int dsIndex)
Returns Datasource object for the given datasource index.
|
Datasource | getDatasource(String dsName)
Returns Datasource object corresponding to the given datasource name.
|
int | getDsCount()
Returns the number of datasources defined in the file
|
int | getDsIndex(String dsName) Returns internal index number for the given datasource name. |
String[] | getDsNames() Returns an array of datasource names defined in RRD. |
Header | getHeader()
Returns RRD header.
|
String | getInfo() |
long | getLastArchiveUpdateTime()
Returns the last time when some of the archives in this RRD was updated. |
double | getLastDatasourceValue(String dsName)
Returns the last stored value for the given datasource.
|
double[] | getLastDatasourceValues()
Returns an array of last datasource values. |
long | getLastUpdateTime()
Returns time of last update operation as timestamp (in seconds).
|
String | getPath()
Returns path to this RRD.
|
RrdAllocator | getRrdAllocator()
Required to implement RrdUpdater interface. |
RrdBackend | getRrdBackend()
Returns backend object for this RRD which performs actual I/O operations.
|
RrdDef | getRrdDef() Returns RRD definition object which can be used to create new RRD with the same creation parameters but with no data in it. Example: RrdDb rrd1 = new RrdDb("original.rrd"); RrdDef def = rrd1.getRrdDef(); // fix path def.setPath("empty_copy.rrd"); // create new RRD file RrdDb rrd2 = new RrdDb(def); |
String | getXml() Returns string representing internal RRD state in XML format. |
boolean | isClosed()
Returns true if the RRD is closed.
|
static void | main(String[] args) |
static void | setDefaultFactory(String factoryName)
Sets default backend factory to be used. |
void | setInfo(String info) |
Constructor used to create new RRD object from the definition. This RRD object will be backed with a storage (backend) of the default type. Initially, storage type defaults to "NIO" (RRD bytes will be put in a file on the disk). Default storage type can be changed with a static setDefaultFactory method call.
New RRD file structure is specified with an object of class
RrdDef
. The underlying RRD storage is created as soon
as the constructor returns.
Typical scenario:
// create new RRD definition RrdDef def = new RrdDef("test.rrd", 300); def.addDatasource("input", DsTypes.DT_COUNTER, 600, 0, Double.NaN); def.addDatasource("output", DsTypes.DT_COUNTER, 600, 0, Double.NaN); def.addArchive(ConsolFuns.CF_AVERAGE, 0.5, 1, 600); def.addArchive(ConsolFuns.CF_AVERAGE, 0.5, 6, 700); def.addArchive(ConsolFuns.CF_AVERAGE, 0.5, 24, 797); def.addArchive(ConsolFuns.CF_AVERAGE, 0.5, 288, 775); def.addArchive(ConsolFuns.CF_MAX, 0.5, 1, 600); def.addArchive(ConsolFuns.CF_MAX, 0.5, 6, 700); def.addArchive(ConsolFuns.CF_MAX, 0.5, 24, 797); def.addArchive(ConsolFuns.CF_MAX, 0.5, 288, 775); // RRD definition is now completed, create the database! RrdDb rrd = new RrdDb(def); // new RRD file has been created on your disk
Parameters: rrdDef Object describing the structure of the new RRD file.
Throws: IOException Thrown in case of I/O error. RrdException Thrown if invalid RrdDef object is supplied.
Constructor used to create new RRD object from the definition object but with a storage (backend) different from default.
JRobin uses factories to create RRD backend objecs. There are three different backend factories supplied with JRobin, and each factory has its unique name:
For example, to create RRD in memory, use the following code
RrdBackendFactory factory = RrdBackendFactory.getFactory("MEMORY"); RrdDb rrdDb = new RrdDb(rrdDef, factory); rrdDb.close();
New RRD file structure is specified with an object of class
RrdDef
. The underlying RRD storage is created as soon
as the constructor returns.
Parameters: rrdDef RRD definition object factory The factory which will be used to create storage for this RRD
Throws: RrdException Thrown if invalid factory or definition is supplied IOException Thrown in case of I/O error
See Also: RrdBackendFactory
Constructor used to open already existing RRD. This RRD object will be backed with a storage (backend) of the default type (file on the disk). Constructor obtains read or read/write access to this RRD.
Parameters: path Path to existing RRD. readOnly Should be set to false
if you want to update
the underlying RRD. If you want just to fetch data from the RRD file
(read-only access), specify true
. If you try to update RRD file
open in read-only mode (readOnly
set to true
),
IOException
will be thrown.
Throws: IOException Thrown in case of I/O error. RrdException Thrown in case of JRobin specific error.
Constructor used to open already existing RRD backed with a storage (backend) different from default. Constructor obtains read or read/write access to this RRD.
Parameters: path Path to existing RRD. readOnly Should be set to false
if you want to update
the underlying RRD. If you want just to fetch data from the RRD file
(read-only access), specify true
. If you try to update RRD file
open in read-only mode (readOnly
set to true
),
IOException
will be thrown. factory Backend factory which will be used for this RRD.
Throws: FileNotFoundException Thrown if the requested file does not exist. IOException Thrown in case of general I/O error (bad RRD file, for example). RrdException Thrown in case of JRobin specific error.
See Also: RrdBackendFactory
Constructor used to open already existing RRD in R/W mode, with a default storage (backend) type (file on the disk).
Parameters: path Path to existing RRD.
Throws: IOException Thrown in case of I/O error. RrdException Thrown in case of JRobin specific error.
Constructor used to open already existing RRD in R/W mode with a storage (backend) type different from default.
Parameters: path Path to existing RRD. factory Backend factory used to create this RRD.
Throws: IOException Thrown in case of I/O error. RrdException Thrown in case of JRobin specific error.
See Also: RrdBackendFactory
Constructor used to create RRD files from external file sources. Supported external file sources are:
rrdtool dump
command).
Newly created RRD will be backed with a default storage (backend) type (file on the disk).
JRobin and RRDTool use the same format for XML dump and this constructor should be used to (re)create JRobin RRD files from XML dumps. First, dump the content of a RRDTool RRD file (use command line):
rrdtool dump original.rrd > original.xml
Than, use the file original.xml
to create JRobin RRD file named
copy.rrd
:
RrdDb rrd = new RrdDb("copy.rrd", "original.xml");
or:
RrdDb rrd = new RrdDb("copy.rrd", "xml:/original.xml");
See documentation for dumpXml()
method
to see how to convert JRobin files to RRDTool's format.
To read RRDTool files directly, specify rrdtool:/
prefix in the
externalPath
argument. For example, to create JRobin compatible file named
copy.rrd
from the file original.rrd
created with RRDTool, use
the following code:
RrdDb rrd = new RrdDb("copy.rrd", "rrdtool:/original.rrd");
Note that the prefix xml:/
or rrdtool:/
is necessary to distinguish
between XML and RRDTool's binary sources. If no prefix is supplied, XML format is assumed
Parameters: rrdPath Path to a RRD file which will be created externalPath Path to an external file which should be imported, with an optional
xml:/
or rrdtool:/
prefix.
Throws: IOException Thrown in case of I/O error RrdException Thrown in case of JRobin specific error
Constructor used to create RRD files from external file sources with a backend type different from default. Supported external file sources are:
rrdtool dump
command).
JRobin and RRDTool use the same format for XML dump and this constructor should be used to (re)create JRobin RRD files from XML dumps. First, dump the content of a RRDTool RRD file (use command line):
rrdtool dump original.rrd > original.xml
Than, use the file original.xml
to create JRobin RRD file named
copy.rrd
:
RrdDb rrd = new RrdDb("copy.rrd", "original.xml");
or:
RrdDb rrd = new RrdDb("copy.rrd", "xml:/original.xml");
See documentation for dumpXml()
method
to see how to convert JRobin files to RRDTool's format.
To read RRDTool files directly, specify rrdtool:/
prefix in the
externalPath
argument. For example, to create JRobin compatible file named
copy.rrd
from the file original.rrd
created with RRDTool, use
the following code:
RrdDb rrd = new RrdDb("copy.rrd", "rrdtool:/original.rrd");
Note that the prefix xml:/
or rrdtool:/
is necessary to distinguish
between XML and RRDTool's binary sources. If no prefix is supplied, XML format is assumed
Parameters: rrdPath Path to RRD which will be created externalPath Path to an external file which should be imported, with an optional
xml:/
or rrdtool:/
prefix. factory Backend factory which will be used to create storage (backend) for this RRD.
Throws: IOException Thrown in case of I/O error RrdException Thrown in case of JRobin specific error
See Also: RrdBackendFactory
Throws: IOException Thrown in case of I/O related error.
Parameters: dsName Datasource name to check
Returns: true
if datasource is present in this RRD, false
otherwise
Throws: IOException Thrown in case of I/O error.
Parameters: other New RrdDb object to copy state to
Throws: IOException Thrown in case of I/O error RrdException Thrown if supplied argument is not a compatible RrdDb object
Prepares fetch request to be executed on this RRD. Use returned
FetchRequest
object and its fetchData()
method to actually fetch data from the RRD file.
Parameters: consolFun Consolidation function to be used in fetch request. Allowed values are "AVERAGE", "MIN", "MAX" and "LAST" (these constants are conveniently defined in the ConsolFuns class). fetchStart Starting timestamp for fetch request. fetchEnd Ending timestamp for fetch request. resolution Fetch resolution (see RRDTool's rrdfetch man page for an explanation of this parameter.
Returns: Request object that should be used to actually fetch data from RRD.
Throws: RrdException In case of JRobin related error (invalid consolidation function or invalid time span).
Prepares fetch request to be executed on this RRD. Use returned
FetchRequest
object and its fetchData()
method to actually fetch data from this RRD. Data will be fetched with the smallest
possible resolution (see RRDTool's
rrdfetch man page
for the explanation of the resolution parameter).
Parameters: consolFun Consolidation function to be used in fetch request. Allowed values are "AVERAGE", "MIN", "MAX" and "LAST" (these constants are conveniently defined in the ConsolFuns class). fetchStart Starting timestamp for fetch request. fetchEnd Ending timestamp for fetch request.
Returns: Request object that should be used to actually fetch data from RRD.
Throws: RrdException In case of JRobin related error (invalid consolidation function or invalid time span).
Creates new sample with the given timestamp and all datasource values set to
'unknown'. Use returned Sample
object to specify
datasource values for the given timestamp. See documentation for
Sample
for an explanation how to do this.
Once populated with data source values, call Sample's
update()
method to actually
store sample in the RRD associated with it.
Parameters: time Sample timestamp rounded to the nearest second (without milliseconds).
Returns: Fresh sample with the given timestamp and all data source values set to 'unknown'.
Throws: IOException Thrown in case of I/O error.
Creates new sample with the current timestamp and all data source values set to
'unknown'. Use returned Sample
object to specify
datasource values for the current timestamp. See documentation for
Sample
for an explanation how to do this.
Once populated with data source values, call Sample's
update()
method to actually
store sample in the RRD associated with it.
Returns: Fresh sample with the current timestamp and all data source values set to 'unknown'.
Throws: IOException Thrown in case of I/O error.
Returns string representing complete internal RRD state. The returned
string can be printed to stdout
and/or used for debugging purposes.
Returns: String representing internal RRD state.
Throws: IOException Thrown in case of I/O related error.
Writes the RRD content to OutputStream using XML format. This format is fully compatible with RRDTool's XML dump format and can be used for conversion purposes or debugging.
Parameters: destination Output stream to receive XML data
Throws: IOException Thrown in case of I/O related error
Dumps internal RRD state to XML file. Use this XML file to convert your JRobin RRD to RRDTool format.
Suppose that you have a JRobin RRD file original.rrd
and you want
to convert it to RRDTool format. First, execute the following java code:
RrdDb rrd = new RrdDb("original.rrd");
rrd.dumpXml("original.xml");
Use original.xml
file to create the corresponding RRDTool file
(from your command line):
rrdtool restore copy.rrd original.xml
Parameters: filename Path to XML file which will be created.
Throws: IOException Thrown in case of I/O related error. RrdException Thrown in case of JRobin related error.
dumpXml
method.
Throws: IOException Thrown in case of I/O related error
getXml
method.
Returns: Internal RRD state in XML format.
Throws: IOException Thrown in case of I/O related error RrdException Thrown in case of JRobin specific error
dumpXml(String)
method.
Throws: IOException Thrown in case of I/O related error RrdException Thrown in case of JRobin specific error
Parameters: consolFun Consolidation function of the datasource. startTime Start time of the time period in seconds. resolution Requested fetch resolution.
Returns: Reference to the best matching archive.
Throws: IOException Thrown in case of I/O related error.
Returns: The number of RRA arcihves defined in the file
Parameters: arcIndex Archive index (zero based)
Returns: Archive object
Parameters: consolFun Consolidation function steps Number of archive steps
Returns: Requested Archive object or null if no such archive could be found
Throws: IOException Thrown in case of I/O error
Parameters: consolFun Consolidation function steps Number of archive steps
Returns: Requested Archive object
Throws: IOException Thrown in case of I/O error RrdException Thrown if no such archive could be found
Returns: All RRD bytes
Throws: IOException Thrown in case of I/O related error.
Returns: Canonical path to RRD file;
Throws: IOException Thrown in case of I/O error or if the underlying backend is not derived from RrdFileBackend.
Parameters: dsIndex Datasource index (zero based)
Returns: Datasource object
Parameters: dsName Datasource name
Returns: Datasource object corresponding to the give datasource name or null if not found.
Throws: IOException Thrown in case of I/O error
Returns: The number of datasources defined in the file
Returns internal index number for the given datasource name. This index is heavily used by jrobin.graph package and has no value outside of it.
Parameters: dsName Data source name.
Returns: Internal index of the given data source name in this RRD.
Throws: RrdException Thrown in case of JRobin related error (invalid data source name, for example) IOException Thrown in case of I/O error.
Returns an array of datasource names defined in RRD.
Returns: Array of datasource names.
Throws: IOException Thrown in case of I/O error.
Returns: Header object
Returns: last time when some of the archives in this RRD was updated
Throws: IOException Thrown in case of I/O error
Parameters: dsName Datasource name
Returns: Last stored value for the given datasource
Throws: IOException Thrown in case of I/O error RrdException Thrown if no datasource in this RrdDb matches the given datasource name
Returns: Array of last datasource values
Throws: IOException Thrown in case of I/O error
Returns: Last update time (in seconds).
Returns: Path to this RRD.
Returns: Allocator object
Returns: RRD backend for this RRD.
Returns RRD definition object which can be used to create new RRD with the same creation parameters but with no data in it.
Example:
RrdDb rrd1 = new RrdDb("original.rrd"); RrdDef def = rrd1.getRrdDef(); // fix path def.setPath("empty_copy.rrd"); // create new RRD file RrdDb rrd2 = new RrdDb(def);
Returns: RRD definition.
Throws: RrdException Thrown in case of JRobin specific error.
Returns string representing internal RRD state in XML format. This format is fully compatible with RRDTool's XML dump format and can be used for conversion purposes or debugging.
Returns: Internal RRD state in XML format.
Throws: IOException Thrown in case of I/O related error RrdException Thrown in case of JRobin specific error
Returns: true if closed, false otherwise
Parameters: factoryName Name of the backend factory to be set as default.
Throws: RrdException Thrown if invalid factory name is supplied, or not called before the first backend object (before the first RrdDb object) is created.