.. _query:

Query
/////

Currently, the ecflow python API provides quite extensive functionality.

However sometimes we just want to query simple state on the command
line, and using the full-blown python API, can seem like overkill.

Query can be used in these simple cases

Query the status of attributes i.e. state, dstate, repeat,event, meter,
variable, limit , limit_max or trigger expression without blocking

-  state return   [unknown \| complete \| queued  \|  aborted \|
   submitted \| active] to standard out

-  dstate return [unknown \| complete \| queued  \|  aborted \|
   submitted \| active \| suspended] to standard out

-  |  repeat   returns current value as a string to standard out, can
     also retrieve the next and previous value of the repeat. See
     examples below
   | The next/prev will always stay within repeat bounds. hence calling
     'next' on the last value of the repeat, will return last value.
   | Likewise calling 'prev' on a repeat that has not started, will
     return the first/start value.

-  event           return 'set' \| 'clear' to standard out

-  meter          return value of the meter to standard out

-  limit              return the current value of the limit

-  limit_max  return the maximum value of the limit

-  label             return new value otherwise the old value

-  variable      return value of the variable, repeat or generated
   variable to standard out, will search up the node tree

-  trigger        returns 'true' if the expression is true, otherwise
   'false'

If this command is called within a '.ecf' script we will additionally log the task calling this command

This is required to aid debugging for excessive use of this command

The command will fail if the node path to the attribute does not exist
in the definition and if:

-  repeat                The repeat is not found

-  event                  The event is not found

-  meter                 The meter is not found

-  limit/limit_max   The limit is not found

-  label                   The label is not found

-  variable No user or generated variable or repeat of that name found
   on node, or any of its parents

-  trigger  Trigger does not parse, or reference to nodes/attributes in
   the expression are not valid

Arguments:

-  arg1 = [ state \| event \| meter \| label \| variable \| trigger \|
   limit \| limit_max ]

-  arg2 = <path> \| <path>:name where name is name of a event,
   meter,limit or variable

-  arg3 = trigger expression (optional)  \| prev \| next    # prev,next
   only used when arg1 is repeat

Usage:

.. code-block:: shell
  
   state=$(ecflow_client --query state /path/to/node)                                              # return node state to standard out
   dstate=$(ecflow_client --query dstate /path/to/node)                                            # state that can includes suspended
   value=$(ecflow_client --query repeat /path/to/node )                                            # return the current value as a string
   value=$(ecflow_client --query repeat /path/to/node   prev  )                                    # return the previous value as a string, does not modify real repeat
   value=$(ecflow_client --query repeat /path/to/node   next)                                      # return the next value as a string, does not modify real repeat
   event=$(ecflow_client --query event /path/to/task/with/event:event_name)                        # return set | clear to standard out
   meter=$(ecflow_client --query meter /path/to/task/with/meter:meter_name)                        # returns the current value of the meter to standard out
   value=$(ecflow_client --query variable /path/to/task/with/var:var_name )                        # returns the variable value to standard out
   limit_value=$(ecflow_client --query limit  /path/to/task/with/limit:limit_name)                 # returns the current value of the limit to standard out
   limit_max=$(ecflow_client --query limit_max /path/to/task/with/limit:limit_name)                # returns the max value of the limit to standard out
   label_value=$(ecflow_client --query label %ECF_NAME%:label_name)                                # returns the current value of the label to standard out
   value=$(ecflow_client --query trigger /path/to/node/with/trigger \"/suite/task == complete\")   # return true if expression evaluates false otherwise
