+
.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. SPDX-License-Identifier: CC-BY-4.0
.. CAUTION: this document is generated from source in doc/src/rtd.
.. Do NOT make changes directly to .rst or .md files.
+
RMR Overview
============================================================================================
-RMr Library
+RMR Library
============================================================================================
NAME
--------------------------------------------------------------------------------------------
-RMr -- Ric Message Router Library
+RMR -- Ric Message Router Library
DESCRIPTION
--------------------------------------------------------------------------------------------
-RMr is a library which provides a user application with the
-ability to send and receive messages to/from other RMr based
+RMR is a library which provides a user application with the
+ability to send and receive messages to/from other RMR based
applications without having to understand the underlying
-messaging transport environment (e.g. Nanomsg) and without
+messaging transport environment (e.g., SI95) and without
needing to know which other endpoint applications are
-currently available and accepting messages. To do this, RMr
+currently available and accepting messages. To do this, RMR
depends on a routing table generated by an external source.
This table is used to determine the destination endpoint of
each message sent by mapping the message type T (supplied by
the message, and in some cases whether that message was sent
to multiple applications.
-RMr functions do provide for the ability to respond to the
+RMR functions do provide for the ability to respond to the
specific source instance of a message allowing for either a
request response, or call response relationship when needed.
The Route Table
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The library must be given a route table which maps message
-numbers to endpoint groups such that each time a message of
-type T is sent, the message is delivered to one member of
-each group associated with T. For example, message type 2
-might route to two different groups where group A consists of
-worker1 and worker2, while group B consists only of logger1.
+types (integers) to endpoint groups such that each time a
+message of type T is sent, the message is delivered to one
+member of each group associated with T. For example, message
+type 2 might route to two different groups where group A has
+two members, worker1 and worker2, while group B has only one
+member, logger1.
+
+The route table consists of a start record, one or more table
+entry records, and an end record. All table records contain
+fields separated with vertical bars (|), and allow for
+trailing comments with the standard shell comment symbol
+(hash, #) provided that the start of the comment is separated
+from the last token on the record by one or more spaces.
+Leading and trailing white space in each field is ignored.
+The route table supports two entry types: *rte* and *mse*.
+
+A *rte* entry defines a message type, an optional sender
+application, and the endpoint(s) which accept the indicated
+message type. However, this format is deprecated and may be
+removed in a future version. An example record appears next.
+
+::
+
+ rte | 1 | app10:4560
+
+
+
+The second type of entry is *mse*. This entry defines a
+message type, an optional sender application, a subscription
+ID, and a collection of endpoints. An example record appears
+next.
+
+::
+
+ mse | 1000,forwarder:43086 | 10 | app2:43086
+
+
It is the responsibility of the route table generator to know
which endpoints belong to which groups, and which groups
accept which message types. Once understood, the route table
-generator publishes a table that is ingested by RMr and used
+generator publishes a table that is ingested by RMR and used
for mapping messages to end points.
The following is a simple route table which causes message
meid_map | start
mme_ar | control1 | meid000 meid001 meid002 meid003 meid004 meid005
- mme_ar | control2 | meid100 meid101 meid102 meid103
+ mme_ar | control2 | meid100 meid101 meid102 meid103
meid_map | end | 2
meid_map | start
mme_ar | control1 | meid000 meid001 meid002 meid003 meid004 meid005
- mme_ar | control2 | meid100 meid101 meid102 meid103
+ mme_ar | control2 | meid100 meid101 meid102 meid103
mme_del| meid200 meid401
- meid_map | end | 1
+ meid_map | end | 3
Route Table Syntax
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The following illustrates the syntax for both the route
-table.
+The following illustrates the syntax for both types of route
+table entries.
::
newrt | start
- mse | <message-type>[,<sender-endpoint>] | <sub-id> <roud-robin-grp>[;<round-robin-grp>]...
+ rte | <message-type>[,<sender-endpoint>] | <round-robin-grp>[;<round-robin-grp>]...
+ mse | <message-type>[,<sender-endpoint>] | <sub-id> | <round-robin-grp>[;<round-robin-grp>]...
newrt | end
A round robin group is one or more endpoints from which one
will be selected to receive the message. When multiple
endpoints are given in a group, they must be separated with a
-comma. An endpoint is the IP address and port (e.g.
-192.158.4.30:8219) or DNS name and port of the application
+comma. An endpoint is an IP address and port (e.g.
+192.158.4.30:8219), or DNS name and port, of the application
that should receive the message type. If multiple round-robin
-groups are given, they must be separated by a semicolon, and
+groups are given, they must be separated by a semicolon.
MEID Map Syntax
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The MEID map is similar to the route table. Entries are used
to add or replace the ownership of one or more MEIDs (mme_ar)
meid_map | start
mme_ar | <owner-endpoint> | <meid> [<meid>...]
mme_del | <meid> [<meid>...]
- meid_map | end | <count>
+ meid_map | end | <count> [| <md5sum>
supplied multiple times, the last observed relationship is
used. Each of the lists of MEIDs are blank separated.
+The optional <md5sum> on the *end* record should be the
+computed MD5 hash for all records which appear between the
+start and and records. This allows for a tighter verification
+that all data was received exactly as the route manager
+transmitted them.
+
Environment
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To enable configuration of the library behaviour outside of
-direct user application control, RMr supports a number of
+direct user application control, RMR supports a number of
environment variables which provide information to the
library. The following is a list of the various environment
-variables, what they control and the defaults which RMr uses
+variables, what they control and the defaults which RMR uses
if undefined.
RMR_ASYNC_CONN
- Allows the asynch connection mode to be turned off (by
- setting the value to 0. When set to 1, or missing from the
- environment, RMR will invoke the connection interface in
- the transport mechanism using the non-blocking (asynch)
+ Allows the async connection mode to be turned off (by
+ setting the value to 0). When set to 1, or missing from
+ the environment, RMR will invoke the connection interface
+ in the transport mechanism using the non-blocking (async)
mode. This will likely result in many "soft failures"
(retry) until the connection is established, but allows
- the application to continue unimpeeded should the
+ the application to continue unimpeded should the
connection be slow to set up.
+
RMR_BIND_IF
- This provides the interface that RMr will bind listen
- ports to allowing for a single interface to be used rather
- than listening across all interfaces. This should be the
- IP address assigned to the interface that RMr should
- listen on, and if not defined RMr will listen on all
- interfaces.
+ This provides the interface that RMR will bind listen
+ ports to, allowing for a single interface to be used
+ rather than listening across all interfaces. This should
+ be the IP address assigned to the interface that RMR
+ should listen on, and if not defined RMR will listen on
+ all interfaces.
+
+
+RMR_CTL_PORT
+
+ This variable defines the port that RMR should open for
+ communications with Route Manager, and other RMR control
+ applications. If not defined, the port 4561 is assumed.
+
+ Previously, the RMR_RTG_SVC (route table generator service
+ port) was used to define this port. However, a future
+ version of Route Manager will require RMR to connect and
+ request tables, thus that variable is now used to supply
+ the Route Manager's well-known address and port.
+
+ To maintain backwards compatibility with the older Route
+ Manager versions, the presence of this variable in the
+ environment will shift RMR's behaviour with respect to the
+ default value used when RMR_RTG_SVC is **not** defined.
+
+ When RMR_CTL_PORT is **defined:** RMR assumes that Route
+ Manager requires RMR to connect and request table updates
+ is made, and the default well-known address for Route
+ manager is used (routemgr:4561).
+
+ When RMR_CTL_PORT is **undefined:** RMR assumes that Route
+ Manager will connect and push table updates, thus the
+ default listen port (4561) is used.
+
+ To avoid any possible misinterpretation and/or incorrect
+ assumptions on the part of RMR, it is recommended that
+ both the RMR_CTL_PORT and RMR_RTG_SVC be defined. In the
+ case where both variables are defined, RMR will behave
+ exactly as is communicated with the variable's values.
+
RMR_RTG_SVC
- RMr opens a TCP listen socket using the port defined by
- this environment variable and expects that the route table
- generator process will connect to this port. If not
- supplied the port 4561 is used.
+ The value of this variable depends on the Route Manager in
+ use.
+
+ When the Route Manager is expecting to connect to an xAPP
+ and push route tables, this variable must indicate the
+ port which RMR should use to listen for these connections.
+
+ When the Route Manager is expecting RMR to connect and
+ request a table update during initialisation, the variable
+ should be the host of the Route Manager process.
+
+ The RMR_CTL_PORT variable (added with the support of
+ sending table update requests to Route manager), controls
+ the behaviour if this variable is not set. See the
+ description of that variable for details.
+
+
+RMR_HR_LOG
+
+ By default RMR writes messages to standard error
+ (incorrectly referred to as log messages) in human
+ readable format. If this environment variable is set to 0,
+ the format of standard error messages might be written in
+ some format not easily read by humans. If missing, a value
+ of 1 is assumed.
+
+
+RMR_LOG_VLEVEL
+
+ This is a numeric value which corresponds to the verbosity
+ level used to limit messages written to standard error.
+ The lower the number the less chatty RMR functions are
+ during execution. The following is the current
+ relationship between the value set on this variable and
+ the messages written:
+
+
+0
+
+ Off; no messages of any sort are written.
+
+
+1
+
+ Only critical messages are written (default if this
+ variable does not exist)
+
+
+2
+
+ Errors and all messages written with a lower value.
+
+
+3
+
+ Warnings and all messages written with a lower value.
+
+
+4
+
+ Informational and all messages written with a lower
+ value.
+
+
+5
+
+ Debugging mode -- all messages written, however this
+ requires RMR to have been compiled with debugging
+ support enabled.
+
+
RMR_RTG_ISRAW
- Is set to 1 if the route table generator is sending
- "plain" messages (not using RMr to send messages, 0 if the
- rtg is using RMr to send. The default is 1 as we don't
- expect the rtg to use RMr.
+ **Deprecated.** Should be set to 1 if the route table
+ generator is sending "plain" messages (not using RMR to
+ send messages), 0 if the RTG is using RMR to send. The
+ default is 1 as we don't expect the RTG to use RMR.
+
+ This variable is only recognised when using the NNG
+ transport library as it is not possible to support NNG
+ "raw" communications with other transport libraries. It is
+ also necessary to match the value of this variable with
+ the capabilities of the Route Manager; at some point in
+ the future RMR will assume that all Route Manager messages
+ will arrive via an RMR connection and will ignore this
+ variable.
RMR_SEED_RT
This is used to supply a static route table which can be
used for debugging, testing, or if no route table
generator process is being used to supply the route table.
- If not defined, no static table is used and RMr will not
+ If not defined, no static table is used and RMR will not
report *ready* until a table is received. The static route
table may contain both the route table (between newrt
start and end records), and the MEID map (between meid_map
- start and end records)
+ start and end records).
RMR_SRC_ID
function to return a response to the sender. If not
supplied RMR will use the hostname which in some container
environments might not be routable.
+
+ The value of this variable is also used for Route Manager
+ messages which are sent via an RMR connection.
RMR_VCTL_FILE
Code Review / ric-plt / lib / rmr.git / blobdiff