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Dominic Oram edited this page Nov 10, 2016 · 21 revisions

Wiki > The Backend System > System components > BlockServer

The BlockServer is responsible for:

  • Creating blocks
  • Creating groups
  • Loading and saving configurations

It can also be used to:

  • Start and stop IOCs via ProcServ

See BlockServer Structure for further information.

What it does

The BlockServer is a Channel Access Server (CAS) written in Python using the PCASpy module. It provides a number of PVs that allow the blocks to be configured (see below) and configurations to be created and loaded. The blocks are PV aliases created using the blocks gateway - a standard channel access gateway running on localhost (127.0.0.1). When a configuration is loaded or the blocks changed then the BlockServer regenerates the PV file for the gateway.

The PV file typically looks something like this:

\(.*\)CS:SB:CJHGAP\(.*\)    ALIAS    \1MOT:JAWS1:HGAP\2
\(.*\)CS:SB:CJVGAP\(.*\)    ALIAS    \1MOT:JAWS1:VGAP\2
\(.*\)CS:SB:A1HGAP\(.*\)    ALIAS    \1MOT:JAWS2:HGAP\2
\(.*\)CS:SB:A1VGAP\(.*\)    ALIAS    \1MOT:JAWS2:VGAP\2
\(.*\)CS:SB:S1HGAP\(.*\)    ALIAS    \1MOT:JAWS3:HGAP\2
\(.*\)CS:SB:S1VGAP\(.*\)    ALIAS    \1MOT:JAWS3:VGAP\2
.*:CS:GATEWAY:.*    ALLOW

Pattern matching is used so that patterns like BLOCKNAME:SP and BLOCKNAME:SP:RBV can be used.

The BlockServer is also responsible for configuring the blocks archiver to log the current blocks.

Configurations are saved in a directory with the configuration's name. The directory contains separate XML files for the blocks, groups, components, IOCs and meta-data that make up the configuration.

The BlockServer also provides a mechanism for starting and stopping IOCs and retrieving the interesting PVs for the currently running IOCs. The BlockServer can start and stop IOCs that are running inside ProcServ as ProcServ provides PVs to enable this. The PVs for the currently running IOCs are read directly from a database.

NOTE: As the BlockServer often needs to send a lot of data via channel access (as a CHAR waveform), it it necessary in some cases to compress the data before sending using zlib. The compressed data is then converted to hex to avoid any null characters been sent across channel access.

Channel Access Commands

Read Commands

BLOCKSERVER:BLOCKNAMES Note: this used by genie_python for checking block names used in CSETs etc. are valid

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:BLOCKNAMES
Returns the block names as compressed and hexed JSON list (CHAR waveform)

BLOCKSERVER:BLOCK_DETAILS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:BLOCK_DETAILS
TODO: add description

BLOCKSERVER:BLOCK_RULES

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:BLOCK_RULES
TODO: add description

BLOCKSERVER:GROUPS Note: This PV is currently used by the web dashboard

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GROUPS
Returns the groups and their blocks as a compressed then hexed JSON list of dictionaries (CHAR waveform).
Example JSON (dehexed and decompressed):
    '[{"blocks": ["testblock1", "testblock2"], "name": "Example group", "component": null},
      {"blocks": ["testblock3", "testblock4"], "name": "Different group", "component": null},
      {"blocks": [], "name": "NONE", "component": null}
     ]'

BLOCKSERVER:GROUP_RULES

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GROUP_RULES
TODO: add description

BLOCKSERVER:CONFIGS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:CONFIGS
Returns a list of the available configurations, including descriptions and the pv associated with the configuration, as compressed then hexed JSON (CHAR waveform)
Example JSON (dehexed and decompressed):
	'[{"name": "Test Config", "description": "A test configuration", "pv": "TEST_CONFIG"}
	  {"name": "Another Config", "description": "To test again", "pv": "ANOTHER_CONFIG"}
	  {"name": "TeSt CoNfIg", "description": "This config has the same name", "pv": "TEST_CONFIG1"}]'

BLOCKSERVER:COMPS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:COMPS
Returns a list of the components available, including descriptions and the pv associated with the configuration, as compressed then hexed JSON (CHAR waveform)
	'[{"name": "Test component", "description": "A test component", "pv": "TEST_COMP"}
	  {"name": "Another component", "description": "To test again", "pv": "ANOTHER_COMP"}
	  {"name": "TeSt ComPonent", "description": "This component has the same name", "pv": "TEST_COMP1"}]'

BLOCKSERVER:GET_RC_OUT

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GET_RC_OUT
Returns a list of the PVs that are outside of their run-control limits as compressed then hexed JSON (CHAR waveform)

BLOCKSERVER:GET_RC_PARS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GET_RC_PARS
Returns a dictionary of the run-control settings for the blocks as compressed then hexed JSON (CHAR waveform)

BLOCKSERVER:GET_CURR_CONFIG_DETAILS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GET_CURR_CONFIG_DETAILS
Returns a compressed and hexed JSON dictionary describing the current configuration or component.
Example JSON (dehexed and decompressed):
    '{"iocs":
             [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
              {"simlevel": "devsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
             ],
      "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
               ],
      "components":
                   [{"name": "comp1"}],
      "groups":
               [{"blocks": ["testblock1"], "name": "Group1", "component": null},
                {"blocks": ["testblock2"], "name": "Group2", "component": null},
                {"blocks": ["testblock3"], "name": "NONE", "component": null}],
      "name": "TESTCONFIG1",
	  "description": "A test configuration",
	  "history": ["2015-02-16"]
     }'

BLOCKSERVER:config_pv:GET_CONFIG_DETAILS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:*config_pv*:GET_CONFIG_DETAILS
Returns a compressed and hexed JSON dictionary describing the configuration with the pv *config_pv*. (To find config pvs use the CONFIGS command)
Example JSON (dehexed and decompressed):
    '{"iocs":
             [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
              {"simlevel": "devsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
             ],
      "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
               ],
      "components":
                   [{"name": "comp1"}],
      "groups":
               [{"blocks": ["testblock1"], "name": "Group1", "component": null},
                {"blocks": ["testblock2"], "name": "Group2", "component": null},
                {"blocks": ["testblock3"], "name": "NONE", "component": null}],
      "name": "TESTCONFIG1",
	  "description": "A test configuration",
	  "history": ["2015-02-16"]
     }'

BLOCKSERVER:component_pv:GET_COMPONENT_DETAILS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:*component_pv*:GET_COMPONENT_DETAILS
Returns a compressed and hexed JSON dictionary describing the component with the pv *component_pv*. (To find component pvs use the COMPS command)
Example JSON (dehexed and decompressed):
    '{"iocs":
             [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
              {"simlevel": "devsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
             ],
      "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
               ],
      "components": [],
      "groups":
               [{"blocks": ["testblock1"], "name": "Group1", "component": null},
                {"blocks": ["testblock2"], "name": "Group2", "component": null},
                {"blocks": ["testblock3"], "name": "NONE", "component": null}],
      "name": "TESTCOMP1",
	  "description": "A test component",
	  "history": ["2015-02-16"]
     }'

BLOCKSERVER:BLANK_CONFIG

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:BLANK_CONFIG
Returns a compressed and hexed JSON dictionary describing a blank configuration.
    '{"iocs": [],
      "blocks": [],
      "components": [],
      "groups": [],
      "name": "",
	  "description": ""
     }'

BLOCKSERVER:CONF_DESC_RULES

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:CONF_DESC_RULES
TODO: add description

BLOCKSERVER:component_pv:DEPENDENCIES

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:*component_pv*:DEPENDENCIES
Returns a list of the configurations that contain the component specified in *component_pv*, formatted as compressed then hexed JSON (CHAR waveform)

BLOCKSERVER:SERVER_STATUS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:SERVER_STATUS
TODO: add description

BLOCKSERVER:BUMPSTRIP_AVAILABLE

Command: caget %MYPVPREFIX%CS:BLOCKSERVER:BUMPSTRIP_AVAILABLE
TODO: add description

BLOCKSERVER:GET_SCREENS

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:GET_SCREENS
Returns a compressed and hexed string containing the XML for the list of the available device screens descriptions (CHAR waveform)

BLOCKSERVER:SCREENS_SCHEMA

Command: caget -S %MYPVPREFIX%CS:BLOCKSERVER:SCREENS_SCHEMA
Returns a compressed and hexed string containing the devices screens XML schema (CHAR waveform)

SYNOPTICS:NAMES

Command: caget -S %MYPVPREFIX%CS:SYNOPTICS:NAMES
Returns a list of the available synoptics formatted as compressed then hexed JSON (CHAR waveform)

SYNOPTICS:synoptic_name:GET

Command: caget -S %MYPVPREFIX%CS:SYNOPTICS:*synoptic_name*:GET
Returns a compressed and hexed string containing the XML for the specified synoptic (CHAR waveform)

SYNOPTICS:GET_DEFAULT

Command: caget -S %MYPVPREFIX%CS:SYNOPTICS:GET_DEFAULT
Returns a compressed and hexed string containing the XML for the current synoptic (CHAR waveform)

SYNOPTICS:_BLANK_:GET

Command: caget -S %MYPVPREFIX%CS:SYNOPTICS:__BLANK__:GET
TODO: add description

SYNOPTICS:SCHEMA

Command: caget -S %MYPVPREFIX%CS:SYNOPTICS:SCHEMA
Returns a compressed and hexed string containing the synoptics XML schema (CHAR waveform)

Write Commands

| NOTE: Unless specified otherwise all of these command return OK if they succeed, otherwise they return an error message. | NOTE: Some of these commands take a few seconds to process, so if done using caput it might be necessary to increase the timeout. |

BLOCKSERVER:LOAD_CONFIG

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:LOAD_CONFIG abcdefabdcdefabcdef1234567890
Loads the specified configuration. Requires a compressed and hexed JSON string. This automatically restarts the blocks gateway and updates the archiver

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:SAVE_CONFIG Note: Used by the client(s) for "save" and "save as" for the current active configuration

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SAVE_CONFIG abcdefabdcdefabcdef1234567890
Saves the current active configuration under the specified name. Requires a compressed and hexed JSON string.
The active configuration's name will be changed to the new name.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:CLEAR_CONFIG

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:CLEAR_CONFIG clear
Send any non-null value to clear the current configuration, i.e. remove blocks, groups and IOCs.
Note: it does not restart the gateway.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:START_IOCS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:START_IOCS abcdefabdcdefabcdef1234567890
Starts the specified IOC or IOCs. Requires compressed and hexed JSON list of IOCS.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:STOP_IOCS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:STOP_IOCS abcdefabdcdefabcdef1234567890
Stops the specified IOC or IOCS. Requires compressed and hexed JSON list of IOCS.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:RESTART_IOCS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:RESTART_IOCS abcdefabdcdefabcdef1234567890
Restarts the specified IOC or IOCs. Requires compressed and hexed JSON list of IOCS.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:SET_RC_PARS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SET_RC_PARS abcdefabdcdefabcdef1234567890
Edits the run-control settings on a block or blocks. Requires compressed and hexed JSON dictionary of dictionaries with the following parameters:
    name - the name of the block
    LOW - the lowlimit
    HIGH - the highlimit
    ENABLE - whether run-control is enable for the block
Example JSON (dehexed and decompressed):
    '{"testblock": {"HIGH": 5, "ENABLE": true, "LOW": -5}}'

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:SET_CURR_CONFIG_DETAILS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SET_CURR_CONFIG_DETAILS abcdefabdcdefabcdef1234567890
Sets the current configuration to the setting specified. Requires compressed and hexed JSON dictionary.
Example JSON (dehexed and decompressed):
    '{"iocs":
             [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
              {"simlevel": "recsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
             ],
      "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
               ],
      "components":
                   [{"name": "comp1"}],
      "groups":
               [{"blocks": ["testblock1"], "name": "Group1", "component": null},
                {"blocks": ["testblock2"], "name": "Group2", "component": null},
                {"blocks": ["testblock3"], "name": "NONE", "component": null}],
      "name": "TESTCONFIG1",
	  "description": "A test configuration",
	  "history": ["2015-02-16"]
     }'

BLOCKSERVER:SAVE_NEW_CONFIG

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SAVE_NEW_CONFIG abcdefabdcdefabcdef1234567890
Saves a configuration to XML without affecting the current active configuration.
This will give an error if trying to overwrite the current active configuration but will allow overwriting of other saved configurations.
Requires compressed and hexed JSON dictionary.

Example JSON (dehexed and decompressed):
	'{"iocs":
			 [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
			  {"simlevel": "recsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
			 ],
	  "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
			   ],
	  "components":
				   [{"name": "comp1"}],
	  "groups":
			   [{"blocks": ["testblock1"], "name": "Group1", "component": null},
				{"blocks": ["testblock2"], "name": "Group2", "component": null},
				{"blocks": ["testblock3"], "name": "NONE", "component": null}],
	  "name": "TESTCONFIG1",
	  "description": "A test configuration",
	  "history": ["2015-02-16"]
	 }'

BLOCKSERVER:SAVE_NEW_COMPONENT

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SAVE_NEW_COMPONENT abcdefabdcdefabcdef1234567890
Saves a component to XML without affecting the current configuration.
This will give an error if trying to overwrite components of the current active configuration.
Requires compressed and hexed JSON dictionary.

Example JSON (dehexed and decompressed):
	'{"iocs":
			 [{"simlevel": "None", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE1", "component": null},
			  {"simlevel": "recsim", "autostart": true, "restart": false, "pvsets": [{"name": "SET", "enabled": "true"}], "pvs": [], "macros": [], "name": "SIMPLE2", "component": null}
			 ],
	  "blocks":
               [{"name": "testblock1", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 10, "log_deadband": 0},
                {"name": "testblock2", "local": true, "pv": "NDWXXX:xxxx:SIMPLE:VALUE1", "component": null, "visible": true, "log_periodic": true, "log_rate": 5, "log_deadband": 0},
                {"name": "testblock3", "local": true, "pv": "NDWXXX:xxxx:EUROTHERM1:RBV", "component": null, "visible": true, "log_periodic": false, "log_rate": 0, "log_deadband": 1.0}
			   ],
	  "groups":
			   [{"blocks": ["testblock1"], "name": "Group1", "component": null},
				{"blocks": ["testblock2"], "name": "Group2", "component": null},
				{"blocks": ["testblock3"], "name": "NONE", "component": null}],
      "components": [],
	  "name": "TESTCOMP1",
	  "description": "A test component",
	  "history": ["2015-02-16"]
	 }'

BLOCKSERVER:DELETE_CONFIGS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:DELETE_CONFIGS abcdefabdcdefabcdef1234567890
Removes a configuration or configurations from the BlockServer and filesystem. Requires a compressed and hexed JSON list of configuration names to remove.
If this is done in error the configuration can be recovered from version control. For removing one configuration only, create a list of one item.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:DELETE_COMPONENTS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:DELETE_COMPONENTS abcdefabdcdefabcdef1234567890
Removes a component or components from the BlockServer and filesystem. Requires a compressed and hexed JSON list of component names to remove.
If this is done in error the component can be recovered from version control. For removing one component only, create a list of one item.

Returns "OK" or an error message (compressed and hexed JSON).

BLOCKSERVER:BUMPSTRIP_AVAILABLE:SP

Command: caput %MYPVPREFIX%CS:BLOCKSERVER:BUMPSTRIP_AVAILABLE:SP
TODO: add description

BLOCKSERVER:SET_SCREENS

Command: caput -S %MYPVPREFIX%CS:BLOCKSERVER:SET_SCREENS
Sets a compressed and hexed XML list of available device screens descriptions.

Returns "OK" or an error message (compressed and hexed JSON).

SYNOPTICS:SET_DETAILS

Command: caput -S %MYPVPREFIX%CS:SYNOPTICS:SET_DETAILS abcdefabdcdefabcdef1234567890
Saves the synoptic with supplied compressed and hexed XML data, saving under the name specified in the XML.

Returns "OK" or an error message (compressed and hexed JSON).

SYNOPTICS:DELETE

Command: caput -S %MYPVPREFIX%CS:SYNOPTICS:DELETE abcdefabdcdefabcdef1234567890
Removes a synoptic from the BlockServer and filesystem. Requires a compressed and hexed JSON list of synoptics names to remove.
If this is done in error the synoptic can be recovered from version control. For removing one synoptic only, create a list of one item.

Returns "OK" or an error message (compressed and hexed JSON).

SYNOPTICS:synoptic_name:SET

Command: caput -S %MYPVPREFIX%CS:SYNOPTICS:*synoptic_name*:SET
TODO: add descriptions

Archiver Settings

Blocks can either be set to log periodically or log on change using the JSON "log_periodic" value.

When log_periodic is true the block will be scanned at the rate given in "log_rate", if the value has changed it will be logged. The "log_deadband" is ignored.

When log_periodic is false the block value will be archived whenever the block changes by the deadband given in "log_deadband". The "log_rate" is ignored.

The File Watcher

The BlockServer also contains a file watcher to aid in the modification of configurations by hand. Although this modification will not happen often it is important that it is handled properly so that necessary changes are made in the client. When any modifications are made to files within the configuration or component directories the file watcher will pick up on it and the following will happen:

  • If the file is not defined by a schema it is considered unrelated to configurations and so an INFO message is logged about the file being modified and no further action is taken.

  • If the modified file is part of a configuration the file watcher will first check that all required xml files are present, check the modification against the schema and then attempt to load the configuration into a dummy holder. If any of these actions fail an error will be logged to the client. Otherwise the relevant PVs will be updated with the new information.

  • If the modified file is part of the active configuration, including within a component used by the configuration, and it passes the above tests the CURR_CONFIG_CHANGED PV is set to 1. The GET_CURR_CONFIG_DETAILS PV is not updated with the new information and the client is therefore expected to reload the configuration for changes to take effect.

In the case of files being deleted the following will happen:

  • If the file is considered unrelated to configurations it will be deleted as normal, including being deleted in version control.

  • If only part of a configuration is deleted an error will be logged and the file will be restored from version control.

  • If a whole component folder is deleted and it is relied upon by other configurations an error is logged and the component is recovered from version control.

  • If the default component is deleted an error is logged and it is restored from version control.

  • If the active configuration is deleted an error is logged and it is restored from version control.

  • If a whole configuration folder is deleted (or a component that is not relied upon) the relevant PVs will be updated and the configuration (or component) will be deleted from version control.

Any log messages written by the file watcher will come from FILEWTCHR.

The Config Version Control

The BlockServer keeps the configurations git repository under /Instrument/Settings/config/NDXXXX up-to-date, adding and committing any changes at runtime. This is done through the ConfigVersionControl class, which simply delegates to the corresponding commands for either git or svn.

The configurations are only committed if the folder is on the correct branch. The rules for the correct branch are:

  • The master branch will never be automatically committed to
  • A branch starting with ND will only be committed to if it is the machine hostname (to avoid accidentally committing to real instruments)
  • Any other branch name is allowed. Developers tend to use fedIDs as branch names

NOTE: Files produced by system tests are treated differently: the ConfigVersionControl checks for files containing the system test prefix in their path, and will NOT add them to version control.

When removing non-system-test files, deletion from the file system is taken care of by the version control library. System test files do not get forwarded to that library, so we have to delete them when we catch them instead.

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