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============================================================================================
Configuration and Deployment
============================================================================================


OVERVIEW
========

The RIC Message Router (RMR) is a library for peer-to-peer
communication. Applications use the library to send and
receive messages where the message routing and endpoint
selection is based on the message type rather than DNS host
name-IP port combinations.

This document contains information regarding the
configuration of RMR when it is embedded by a *user
application* . RMR itself is a library, not a deployable
entity.


Configuration
-------------

Many aspects of RMR behavior are controlled via environment
variables. These values are read when a user application
invokes the RMR initialization function. This allows these
variables to be set before the application is started as a
function of the true environment, or set by the application
as a means for the application to influence RMR's behaviour.
The following is a list of environment variables which RMR
recognizes. Also see the main RMR manual page in the
development package for more details.

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      * - **RMR_ASYNC_CONN**
        -
          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 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.

      * - **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_RTREQ_FREQ**
        -
          When RMR needs a new route table it will send a request once
          every ``n`` seconds. The default value for ``n`` is 5, but
          can be changed if this variable is set prior to invoking the
          process. Accepted values are between 1 and 300 inclusive.

      * - **RMR_RTG_SVC**
        -
          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:


              .. list-table::
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                :class: borderless

                * - **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**
        -
          **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 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).

      * - **RMR_SRC_ID**
        -
          This is either the name or IP address which is placed into
          outbound messages as the message source. This will used when
          an RMR based application uses the rmr_rts_msg() 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_STASH_RT**
        -
          Names the file where RMR should write the latest update it
          receives from the source of route tables (generally Route
          Manager). This is meant to assist with debugging and/or
          troubleshooting when it is suspected that route information
          isn't being sent and/or received correctly. If this variable
          is not given, RMR will save the last update using the
          ``RMR_SEED_RT`` variable value and adding a ``.stash`` suffix
          to the filename so as not to overwrite the static table.

      * - **RMR_VCTL_FILE**
        -
          This supplies the name of a verbosity control file. The core
          RMR functions do not produce messages unless there is a
          critical failure. However, the route table collection thread,
          not a part of the main message processing component, can
          write additional messages to standard error. If this variable
          is set, RMR will extract the verbosity level for these
          messages (0 is silent) from the first line of the file.
          Changes to the file are detected and thus the level can be
          changed dynamically, however RMR will only suss out this
          variable during initialisation, so it is impossible to enable
          verbosity after startup.

      * - **RMR_WARNINGS**
        -
          If set to 1, RMR will write some warnings which are
          non-performance impacting. If the variable is not defined, or
          set to 0, RMR will not write these additional warnings.