Saving Parameters in a YAML File

param.yaml Configuration Example

This file is used to store system configuration parameters. The format complies with the general YAML file specifications, that is, the key-value pair format. Both the key and value can be modified. The following is a configuration example:

param1:
  a: 12
  b: true
  c: "node"
param2: 234

When parsing the YAML file, the configuration management module needs to obtain parameter values through the CfgMgr::Get interface. The principle is to obtain the corresponding value based on the specified key value (the content before the colon is the key value). The following is a parsing example. For details about the namespace definition, see yaml_path.yaml Configuration Example.

/namespace/param1/a: 12
/namespace/param1/b: true
/namespace/param1/c: "node"
/namespace/param2: 234

If the parameters saved in the YAML file are in array format, use hyphens (-) to distinguish each group of parameters. The following is a configuration example:

module:
  -
    key1: aaa
    key2: bbb
  -
    key1: ccc
    key2: ddd

When the configuration management module parses the YAML file, underscores (_) and sequence numbers (from top to bottom, the array sequence number starts from 0) need to be added to the key value. The parsing example is as follows:

/namespace/module_0/key1: aaa
/namespace/module_0/key2: bbb
/namespace/module_1/key1: ccc
/namespace/module_1/key2: ddd

yaml_path.yaml Configuration Example

This file is used to specify the path for storing the param.yaml parameter file and related attribute information. The following is a configuration example:

yaml_path:
  - path: /etc/param.yaml
    namespace: /demo
    group: global
    version: 1.0

  - path: /etc/cfg/robot_sensor_config/${robot_type}/${robot_id}/pnc_configs/parking_params.yaml
    namespace: /pnc
    group: global
    version: 1.0

  - path: ${parameters_path}/robot_sensor_config/${robot_type}/${robot_id}/pnc_configs
    namespace: /pnc
    group: global
    version: 1.0 

These parameters are fixed and cannot be modified. The meanings of these parameters are as follows:

• yaml_path: indicates the function of the YAML file. It is used to specify the path for storing the parameter file and related attribute information.
• path: indicates the path or directory for storing the param.yaml parameter file.
  • If a directory is specified, all YAML files in the directory are loaded by default.
  • If the value of path contains variables, add ${variable} to identify the variables and define the variables in the cfgmgr_env.yaml file. For details, see cfgmgr_env.yaml Configuration Example.
• namespace: indicates the name domain of the path parameter. This parameter can be left blank.
• group: indicates the parameter group to which the path parameter belongs. The group corresponds to the virtual resource file. You can configure the read and write permissions of each process by group. This parameter is reserved and does not need to be configured. The default value is global, indicating that all processes have the read and write permissions.
• version: indicates the version of the path parameter. This parameter is reserved and does not need to be configured.

cfgmgr_env.yaml Configuration Example

This file is used to configure the storage path and related variables of yaml_path.yaml. A configuration example is as follows:

cfgmgr_env:                          # Fixed field, which cannot be changed.
  yaml_path:                         # Fixed field, which cannot be changed.
    - /etc/yaml/pnc_yaml_path.yaml
    - /etc/yaml/fusion_yaml_path.yaml  

  # The following is an example of variable configuration. You can add, delete, and modify variables as required.
  robot_factory: xxxxx
  robot_type: vw_magotan_1.1
  robot_sensor: xxx
  robot_id: LFV3A23C5J3010804
  scenario: map

You can modify the parameters in the cfgmgr_env section. After the modification, you need to reload the YAML file through the CfgMgr::Reload interface.

Key parameters are described as follows:

• cfgmgr_env: fixed parameter name, which cannot be changed.
• yaml_path: path of the yaml_path.yaml file of each module. You must configure at least one path and can configure multiple paths. The CfgMgr determines the YAML files to be loaded based on the xxx_yaml_path.yaml file.
• Variable (for example, robot model): The value is a key-value pair. Both the key and value can be modified. Variables can be used as a part of the YAML file path to load different YAML files for different robots.