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diff --git a/doc/sysdbql.7.txt b/doc/sysdbql.7.txt
index 8842c01033226227085ce36cdfde5b04a3f6e94d..9c8b3057cf062eea4ca7fe9720bd9483cdbe5e39 100644 (file)
--- a/doc/sysdbql.7.txt
+++ b/doc/sysdbql.7.txt
FETCH host 'some.host.name';
- LOOKUP hosts MATCHING attribute[architecture] = 'amd64'
- FILTER .age < 5 * .interval;
+ LOOKUP hosts MATCHING attribute['architecture'] = 'amd64'
+ AND 'backend::collectd::unixsock' in backend
+ FILTER age < 5 * interval;
+
+ STORE host attribute 'some.host.name'.'key' 123.45
+ LAST UPDATE 2001-02-03 04:05:06;
DESCRIPTION
-----------
the Standard Query Language (SQL) supported by relational database management
systems (RDBMS) but specialized for SysDB's use-case.
+Besides querying data, SysQL may also be used to store or update objects in
+SysDB.
+
QUERY COMMANDS
--------------
Each command is terminated by a semicolon. The following commands are
available to retrieve information from SysDB:
*LIST* hosts|services|metrics [*FILTER* '<filter_condition>']::
-Retrieve a sorted (by name) list of all hosts currently stored in SysDB along
-with their services or metrics if requested. The return value is a list of
-hosts where each host specification includes its name, the timestamp of the
-last update of the object known to SysDB and an approximation of the interval
-with which the host was updated. When listing services or metrics, the
-respective objects will be included for each host as well. If a filter
+Retrieve a sorted (by name) list of all objects of the specified type
+currently stored in SysDB. The return value is a list of objects including
+their names, the timestamp of the last update and an approximation of the
+interval with which the host was updated. When listing services or metrics,
+the respective objects will be grouped by host. If a filter condition is
+specified, only objects matching that filter will be included in the reply.
+See the section "FILTER clause" for more details about how to specify the
+search and filter conditions.
+
+*FETCH* host '<hostname>' [*FILTER* '<filter_condition>']::
+*FETCH* service|metric '<hostname>'.'<name>' [*FILTER* '<filter_condition>']::
+Retrieve detailed information about the specified object. The return value
+includes the full object including all of its attributes and child objects.
+If the named object does not exist, an error is returned. If a filter
condition is specified, only objects matching that filter will be included in
the reply. See the section "FILTER clause" for more details about how to
specify the search and filter conditions.
-*FETCH* host '<hostname>' [*FILTER* '<filter_condition>']::
-Retrieve detailed information about the specified host object. The return
-value includes the hostname, a list of services referenced by the host, and a
-list of attributes for the host and each service. If the host does not exist,
-an error is returned. If a filter condition is specified, only objects
-matching that filter will be included in the reply. See the section "FILTER
-clause" for more details about how to specify the search and filter
-conditions.
-
-*LOOKUP* hosts *MATCHING* '<search_condition>' [*FILTER* '<filter_condition>']::
-Retrieve detailed information about all host objects matching the specified
-search condition. The return value is a list of detailed information for each
-matching host providing the same details as returned by the *FETCH* command.
-If no host matches the search criteria, it's not considered an error. Instead,
-an empty list is returned. If a filter condition is specified, only objects
-matching that filter will be included in the reply. See the sections "MATCHING
-clause" and "FILTER clause" for more details about how to specify the search
-and filter conditions.
+*LOOKUP* hosts|services|metrics [*MATCHING* '<search_condition>'] [*FILTER* '<filter_condition>']::
+Retrieve detailed information about all objects matching the specified search
+condition. The return value is a list of detailed information for each
+matching object providing the same details as returned by the *FETCH* command.
+If no object matches the search criteria, it's not considered an error.
+Instead, an empty list is returned. If a filter condition is specified, only
+objects matching that filter will be included in the reply. See the sections
+"MATCHING clause" and "FILTER clause" for more details about how to specify
+the search and filter conditions.
*TIMESERIES* '<hostname>'.'<metric>' [START '<datetime>'] [END '<datetime>']::
+*TIMESERIES* '<hostname>'.'<metric>'\[<data-source, ...\] [START '<datetime>'] [END '<datetime>']::
Retrieve a time-series for the specified host's metric. The data is retrieved
from a backend data-store based on information provided by the respective
query plugin. The return value includes the actual start and end time of the
-time-series and one or multiple sequences of time-stamp / value pairs. If the
-metric does not exist or if the backend data-store is not supported, an error
-is returned.
+time-series and one or multiple sequences of time-stamp / value pairs. If any
+data-source names have been specified, only those data-sources will be
+returned. If the metric or a specified data-source does not exist or if the
+backend data-store is not supported, an error is returned.
MATCHING clause
~~~~~~~~~~~~~~~
The *MATCHING* clause in a query specifies a boolean expression which is used
-to match host objects based on their names, their attributes, or services
-referenced by the host. Each *MATCHING* clause may be made up of one or
-multiple subexpressions each matching on one criteria. The following
-subexpressions are supported by SysDB:
+to match objects based on their fields, attributes, or child objects. Any
+object for which the expression evaluates to true will be included in the
+result set according to the rules set by the actual query.
+
+FILTER clause
+~~~~~~~~~~~~~
+The *FILTER* clause in a query specifies a boolean expression which is used to
+filter objects included in the query's response. The filter is applied to
+hosts, services, and attributes alike and, thus, will usually be based on the
+core properties of the stored objects. The basic syntax for filter clauses is
+the same as for matching clauses.
+
+Expressions
+~~~~~~~~~~~
+Expressions form the basic building block for all queries. Boolean expressions
+select objects based on the values of arithmetic expressions which operate on
+object specific values (fields) or constant values.
+
+Boolean expressions may use the following operators:
-'<field>' '<operator>' '<value>'::
- Match a named field against the specified value. See below for what fields
- and operators are supported.
+'<expression>' *AND* '<expression>'::
+'<expression>' *OR* '<expression>'::
+ Evaluates to the logical AND or logical OR of the specified
+ subexpressions.
-*NOT* '<subexpression>'::
+*NOT* '<expression>'::
Invert the boolean result of the specified subexpression.
-'<subexpression>' *AND* '<subexpression>'::
-'<subexpression>' *OR* '<subexpression>'::
- Combine multiple subexpressions using logical AND or logical OR.
+'<expression>' '<cmp>' '<expression>'::
+ Compare the values of two expressions using any compare operator (see
+ below). Evaluates to either true or false. Comparing any value with a NULL
+ value always evaluates to false. The data types of the two values have to
+ match except for a few cases as noted in the documentation of the
+ respective operator.
+
+*ANY* '<iterable>' '<cmp>' '<expression>'::
+ Compares each element of an iterable using any compare operator. Evaluates
+ to true if any of the elements matches or false if no such elements exist.
+ Otherwise, the same rules as for other comparison operations apply.
+ Attributes, a host's services and metrics, and arrays are iterables.
+
+*ALL* '<iterable>' '<cmp>' '<expression>'::
+ *ALL* is similar to the *ANY* operator but matches if all elements match
+ or if no elements exist.
+
+'<expression>' *IS NULL*::
+'<expression>' *IS NOT NULL*::
+ Check whether an expression evaluates to a NULL value (or not). An
+ expression evaluates to NULL if the queried object does not exist (e.g.,
+ when accessing an attribute value).
+
+'<expression>' *IS TRUE*::
+'<expression>' *IS NOT TRUE*::
+'<expression>' *IS FALSE*::
+'<expression>' *IS NOT FALSE*::
+ Check whether an expression evaluates to a boolean *true* or *false* value
+ (or not).
+
+'<expression>' *IN* '<expression>'::
+'<expression>' *NOT IN* '<expression>'::
+ Checks whether the value of the first expression is included in the value
+ of the second expression (or not). The second value has to be an array
+ value (e.g., *backend* field) and the type of the first value has to match
+ the array's element type. The first value may also be an array. In this
+ case, the expression evaluates to true if all elements of that array are
+ included in the second array where order does not matter.
+
+Parentheses ('()') may be used around subexpressions to group them and enforce
+precedence.
The following fields may be queried:
-*host*::
- The full name of the host.
+*name*::
+ The canonicalized name of the object. The type of this field is string.
-*service*::
- The full service name as referenced by the host.
-
-*attribute*::
- The full name of a host attribute.
+*last_update*::
+ The timestamp of the last update of the object. This value is based on
+ information provided by the queried backend if possible. The type of this
+ field is date-time.
-*attribute[*'<name>'*]*::
- The value of the named host attribute. If an attribute of the specified
- does not exist, each comparison is treated as if the value does not match.
- See the documentation for the *IS NULL* and *IS NOT NULL* operators for
- ways to check if an attribute exists.
+*age*::
+ The amount of time since the last update of the object. The type of this
+ field is date-time.
-'<value>' may either be a string (when matching by object names) or match the
-type of the attribute's value (when matching attribute values). Attribute
-values may either be a string, integer, decimal number, or a date-time value
-(booleans and binary data are not supported by the frontend yet). See the
-section "DATA TYPES" for more details about how specify each data-type.
+*interval*::
+ The interval with which the object gets updated. This value is determined
+ automatically based on a moving average determined from the update
+ timestamps of an object. It depends on the update timestamps as provided
+ by the backend (if available) and SysDB's query interval. The type of this
+ field is date-time.
-When comparing an attribute's value using a regular expression matcher, the
-value will be cast to a string before doing so. No other casts are supported
-at this time.
+*backend*::
+ The name of the backend (plugin) providing the data. The type of this
+ field is array of strings.
-The following operators may be used to match field values:
+*attribute[*'<name>'*]*::
+ The value of the object's named attribute. If an attribute of the
+ specified name does not exist, each comparison is treated as if the value
+ does not match. See the documentation for the *IS NULL* and *IS NOT NULL*
+ operators for ways to check if an attribute exists. The value of an
+ attribute may be of any of the supported data types. There is no schema
+ specifying each attribute's data type which means that the parser cannot
+ do any type checks. Thus, in case the data types mismatch when comparing
+ an attribute value with some other value, the two values will be cast to
+ strings before comparing them.
+
+*value*::
+ *(Attributes only)* The value of an attribute. Attributes may be accessed
+ by iterating the values of the parent object and this field provides
+ access to its value in that case. See *attribute[*'<name>'*]* above for
+ details about how to handle attribute values.
+
+*timeseries*::
+ *(Metrics only)* A boolean value indicating whether a backend data-store
+ for fetching time-series information is known to SysDB. See the section
+ "Metrics and Time-Series" in manpage:sysdb[7] for details.
+
+Field expressions may be applied to parent or child nodes. For example, a
+host's services are child objects and the host is the parent of the service
+objects. This is done using typed expressions:
+
+host|service|metric.'<field>'::
+ Evaluate the field in the context of the respective parent or child.
+ Currently, this is limited to services or metrics referencing their parent
+ host.
+
+The following logical operators are supported by SysDB. Unless otherwise
+noted, the data types of the left hand and right hand side have to match.
*=*::
- Evaluates to true if the field value exactly matches the specified value.
+ Checks two values for equality.
*!=*::
- Evaluates to true if the field value does not match the exact specified
- value.
+ Checks two values for inequality.
*=~*::
- Evaluates to true if the field value matches the specified regular
- expression. SysDB uses POSIX extended regular expressions.
+ Checks if a value matches a regular expression. The regex pattern has to
+ be specified as a string but the value may be of any type and will be cast
+ to a string before evaluating the regular expression. SysDB uses POSIX
+ extended regular expressions.
*!~*::
- Evalues to true if the field value does not match the specified regular
- expression.
-
-The following operators may be used, in addition, to match attribute values:
+ Checks if a value does not match a regular expression. The same rules
+ apply as for the *=~* operator.
*<*, *\<=*, *>=*, *>*::
- Evaluates to true if the attribute value is less than, less than or equal
- to, greater than or equal to or greater than the specified value.
-
-In addition, a named attribute may be checked for existence using the *IS
-NULL* and *IS NOT NULL* operators. An attribute is considered to be *NULL* if
-it is not set for a host.
-
-FILTER clause
-~~~~~~~~~~~~~
-The *FILTER* clause in a query specifies a boolean expression which is used to
-filter objects included in the query's response. The filter is applied to
-hosts, services, and attributes alike and, thus, will usually be based on the
-core properties of the stored objects. The basic syntax for filter clauses is
-the same as for matching clauses (see the description about subexpressions
-above).
-
-The following fields (core properties) of stored objects may be queried:
-
-*.last_update*::
- The timestamp of the last update of the object. This value is based on
- information provided by the queried backend if possible.
-
-*.age*::
- The amount of time since the last update of the object.
-
-*.interval*::
- The interval with which the object gets updated. This value is determined
- automatically based on a moving average determined from the update
- timestamps of an object. It depends on the update timestamps as provided
- by the backend (if available) and SysDB's query interval.
-
-*.backend*::
- The name of the backend (plugin) providing the data.
-
-The type of the *last_update*, *age*, and *interval* fields is date-time and
-the type of the *backend* field is string. All conditional operators may be
-used to compare the date-time fields (but not regular expression or *IS NULL*
-operators). The backend field may only be matched by (in)equality. Each object
-may be provided by multiple backends. The filter matches if the specified
-value matches any of them.
+ Checks whether a value compares less than, less than or equal to, greater
+ than or equal, or greater than some other value.
+
+The following arithmetic operators are supported by SysDB. Unless otherwise
+noted, the data types of the left hand and right hand side have to match.
+
+*+*::
+*-*::
+ Add or subtract two numeric or date-time values.
+
+***::
+*/*::
+ Multiple or divide two numeric or data-time values. A date-time value may
+ be multiplied with a numeric value or divided by a numeric value. The
+ result will then be a date-time value.
+
+*%*::
+ Modulo operator (remainder of division). Same rules for data types apply
+ as for division.
+
+*||*::
+ Concatenate string or array values.
+
+STORING DATA
+------------
+The *STORE* command may be used to store or update an object in SysDB. Each
+command is terminated by a semicolon. The following variants are available for
+storing the different data types:
+
+*STORE* host '<name>' [*LAST UPDATE* '<datetime>']::
+*STORE* service|metric '<hostname>'.'<name>' [*LAST UPDATE* '<datetime>']::
+*STORE* host attribute '<hostname>'.'<key>' '<value>' [*LAST UPDATE* '<datetime>']::
+*STORE* service|metric attribute '<hostname>'.'<name>'.'<key>' '<value>' [*LAST UPDATE* '<datetime>']::
+ Store an object of the specified type and name. For services, metrics, and
+ attributes, the name is prepended with the parent object name separated by
+ a dot ('.'). Optionally, the time-stamp of the object's last update may be
+ provided as well. If omitted, the current time on the server will be used
+ instead.
+
+*STORE* metric '<hostname>'.'<name>' STORE '<type>' '<id>' ['<datetime>'] [*LAST UPDATE* '<datetime>']::
+ Store a metric and provide information about the metric store associated
+ with it. A metric store describes how to access a metric's data and can be
+ used to retrieve time-series information associated with the metric. See
+ the manpage:sysdb[7] manpage for details.
+.
+ Note that the metric store information will be forwarded to the server
+ unmodified. That is, they need to be specified in a way such that the
+ server can make sense out of them. Else, retrieval of time-series data
+ will fail.
DATA TYPES
----------
(minutes), *s* (seconds), *ms* (milliseconds), *us* (microseconds), or
*ns* (nanoseconds). Note that years and months are approximations.
+*Array constants*::
+ An array stores of one or more values of the same type. It may be
+ specified as a comma-separated list of constant values enclosed in square
+ brackets ('[<elem1>,<elem2>,...]'). For each value, the same rules apply
+ as for a regular constant value of that type.
+
RESPONSE FORMAT
---------------
The JavaScript Object Notation (JSON) format, as specified in RFC 4627, is
-used in all replies from the server. http://www.ietf.org/rfc/rfc4627.txt
+used in all query replies from the server. http://www.ietf.org/rfc/rfc4627.txt
+
+For all other commands, the reply will be a message string.
EXAMPLES
--------
[{
"name": "host1.example.com",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus']
},{
"name": "host2.example.com",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "10s",
+ "backend": ['backend::mk-livestatus','backend::collectd::unixsock']
}]
FETCH host 'host1.example.com';
"name": "host1.example.com",
"last_update": "2001-02-03 04:05:06 +0700",
"update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus'],
"attributes": [{
"name": "architecture",
"value": "amd64",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus']
},{
...
}],
"services": [{
"name": "some service",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus']
},{
...
}]}
- LOOKUP hosts MATCHING attribute[architecture] = 'amd64';
+ LOOKUP hosts MATCHING attribute['architecture'] = 'amd64';
[{
"name": "host1.example.com",
"last_update": "2001-02-03 04:05:06 +0700",
"update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus'],
"attributes": [{
"name": "architecture",
"value": "amd64",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus']
},{
...
}],
"services": [{
"name": "some service",
"last_update": "2001-02-03 04:05:06 +0700",
- "update_interval": "5m4s"
+ "update_interval": "5m4s",
+ "backend": ['backend::mk-livestatus']
},{
...
}]},{
--------
manpage:sysdb[1], manpage:sysdb[7]
+RFC 4627 (JSON): http://www.ietf.org/rfc/rfc4627.txt
+
The SysDB homepage: https://sysdb.io/
AUTHOR