Rose Configuration Format

A configuration in Rose is normally represented by a directory with the following:

  • a configuration file in a modified INI format.

  • (optionally) files containing data that cannot easily be represented by the INI format.

We have added the following conventions into the Rose configuration format:

  1. The file name is normally called rose*.conf, e.g. rose.conf, rose-app.conf, rose-meta.conf, etc.

  2. Only a hash # in the beginning of a line starts a comment. Empty lines and lines with only white spaces are ignored. There is no support for trailing comments. Comments are normally ignored when a configuration file is loaded. However, some comments are loaded if the following conditions are met:

    • Comment lines at the beginning of a configuration file up to but not including the 1st blank line or the 1st setting are comment lines associated with the file. They will re-appear at the top of the file when it is re-dumped.

    • Comment lines between a blank line and the next setting, and the comment lines between the previous setting and the next setting are comments associated with the next setting. The comment lines associated with a setting will re-appear before the setting when the file is re-dumped.

  3. Only the equal sign = is used to delimit a key-value pair - because the colon : may be used in keys of namelist declarations.

  4. A key-value pair declaration does not have to live under a section declaration. Such a declaration lives directly under the root level.

  5. Key-value pair declarations following a line with only [] are placed directly under the root level.

  6. Declarations are case sensitive. When dealing with case-insensitive inputs such as Fortran logicals or numbers in scientific notation, lowercase values should be used.

  7. When writing namelist inputs, keys should be lowercase.

  8. Declarations start at column 1. Continuations start at column >1.

    • Each line is stripped of leading and trailing spaces.

    • A newline \n character is prefixed to each continuation line.

    • If a continuation line has a leading equal sign = character, it is stripped from the line. This is useful for retaining leading white spaces in a continuation line.

  9. A single exclamation ! or a double exclamation !! in front of a section (i.e. [!SECTION]) or key=value pair (i.e. !key=value) denotes an ignored setting.

    • E.g. It will be ignored in run time but may be used by other Rose utilities.

    • A single exclamation denotes a user-ignored setting.

    • A double exclamation denotes a program-ignored setting. E.g. rose config-edit may use a double exclamation to switch off a setting according to the setting metadata.

  10. The open square bracket ([) and close square bracket (]) characters cannot be used within a section declaration. E.g. [[hello], [hello]], [hello [world] and beyond] should all be errors on parsing.

  11. If a section is declared twice in a file, the later section will append settings to the earlier one. If the same key in the same section is declared twice, the later value will override the earlier one. This logic applies to the state of a setting as well.

  12. Once the file is parsed, declaration ordering is insignificant.


    Do not assume order of environment variables.

  13. Values of settings accept syntax such as $NAME or ${NAME} for environment variable substitution.


# This is line 1 of the comment for this file.
# This is line 2 of the comment for this file.

# This comment will be ignored.

# This is a comment for section-1.
# This is a comment for key-1.
key-1=value 1
# This comment will be ignored.

# This is line 1 of the comment for key-2.
# This is line 2 of the comment for key-2.
key-2=value 2 line 1
      value 2 line 2
# This is a comment for key-3.
key-3=value 3 line 1
     =    value 3 line 2 has leading indentation.
     =    value 3 line 3 is blank. This is line 4.

# section-2 is user-ignored.
key-4=value 4
# ...

# key-5 is program ignored.
!!key-5=value 5


In this document, the shorthand SECTION=KEY=VALUE is used to represent a KEY=VALUE pair in a [SECTION] of an INI format file.


Suite configurations should be portable between users (at least at the same site). E.g.: another user should be able to run the same suite:

  • without making ANY changes to it.

  • without having to add/modify things in their $HOME/.profile.

Input configurations should be programming language neutral.

  • Any processing logic should be application/version independent, generic and future-proof.

  • Data structure should be represented in formats easily understood and manipulatable by a human and a computer.

The life cycles of application configurations in a suite may differ from that of the suite.

  • The configuration of an application may be independent of the suite.

  • The configuration of an application should be portable between suitable suites.

The configurations are independent of the utilities. For example, the configuration metadata for the suite and application configurations will drive the Rose config editor GUI, but will not be bound or restricted by it.

Optional Configuration

In a Rose configuration directory, we can add an opt/ sub-directory for optional configuration files. Optional configuration files contain additional configuration, which can be selected at run time to override the configuration in the main rose-${TYPE}.conf file. The name of each optional configuration should follow the syntax rose-${TYPE}-${KEY}.conf, where ${KEY} is a short name to describe the override functionality of the optional configuration file.

A root level opts=KEY ... setting in the main configuration will tell the run time program to load the relevant optional configurations in the opt/ sub-directory at run time. Individual Rose utilities may also read optional configuration keys from environment variables and/or command line options.

Where multiple $KEY settings are given, the optional configurations are applied in that order - for example, a setting:

opts=ketchup mayonnaise

implies loading the optional configuration rose-app-ketchup.conf and then the optional configuration rose-app-mayonnaise.conf, which may override the previous one.

By default, a Rose command will fail if an optional configuration file is missing. However, if you put the optional configuration key in brackets, then the optional configuration file is allowed to be missing. E.g.:

opts=ketchup (mayonnaise)

In the above example, rose-app-mayonnaise.conf can be missing.

Some Rose utilities (e.g. rose task-run, rose app-run, etc) allow optional configurations to be selected at run time using:

  1. The ROSE_APP_OPT_CONF_KEYS Environment variables.

  2. The command line options --opt-conf-key=KEY or -O KEY.


See reference of individual commands for detail.


By default optional configurations must exist else an error will be raised. To specify an optional configuration which may be missing write the name of the configuration inside parenthesis (e.g. (foo)).

Optional Configurations and Metadata

Metadata utilities such as rose app-upgrade and rose macro treat each main + optional configuration as a separate entity to be transformed, upgraded, or validated. Use cases with more than one optional configuration are not handled.

When transforming or upgrading, each optional configuration is treated separately and re-created after the transform as a functional difference from the main upgraded configuration.

The logic for transforming or upgrading a main configuration C with optional configurations O1 and O2 into a new main configuration Ct and new optional configurations O1t and O2t can be represented like this:

C => Ct
C + O1 => C1t
C + O2 => C2t
O1t = C1t - Ct
O2t = C2t - Ct

Import Configuration

A root level import=PATH1 PATH2... setting in the main configuration will tell Rose utilities to search for configurations at PATH1, PATH2 (and so on) and inherit configuration and files from them if found.


At the moment, use of this is only encouraged for configuration metadata.

Re-define Configuration at Run Time

Some Rose utilities (e.g. rose task-run, rose app-run, etc) allow you to re-define configuration settings at run time using the --define=[SECTION]NAME=VALUE or -D [SECTION]NAME=VALUE options on the command line. This would add new settings or override any settings defined in the main and optional configurations. E.g.:

# Set [env]FOO=foo, and [env]BAR=bar
# (Overriding any original settings of [env]FOO or [env]BAR)
rose task-run -D '[env]FOO=foo' -D '[env]BAR=bar'

# Switch off [env]BAZ
rose task-run -D '[env]!BAZ='