cs.sqltags 20210404

Simple SQL based tagging and the associated `sqltags` command line script, supporting both tagged named objects and tagged timestamped log entries.

Simple SQL based tagging and the associated sqltags command line script, supporting both tagged named objects and tagged timestamped log entries.

Latest release 20210404:

• SQLTags.getitem: when autocreating an entity, do it in a new session so that the entity is commited to the database before any further use.
• SQLTagsCommand: new cmd_dbshell to drop you into the database.

Compared to cs.fstags and its associated fstags command, this is oriented towards large numbers of items not naturally associated with filesystem objects. My initial use case is an activity log, but I'm probably going to use it for ontologies as well.

Many basic tasks can be performed with the sqltags command line utility, documented under the SQLTagsCommand class below.

Class BaseSQLTagsCommand(cs.cmdutils.BaseCommand,cs.tagset.TagsCommandMixin)

Common features for commands oriented around an SQLTags database.

Command line usage:

Usage: BaseSQLTagsCommand [-f db_url] subcommand [...]
  -f db_url SQLAlchemy database URL or filename.
            Default from $SQLTAGS_DBURL (default '~/var/sqltags.sqlite').
  Subcommands:
    dbshell
      Start an interactive database shell.
    edit criteria...
      Edit the entities specified by criteria.
    export {tag[=value]|-tag}...
      Export entities matching all the constraints.
      The output format is CSV data with the following columns:
      * `unixtime`: the entity unixtime, a float
      * `id`: the entity database row id, an integer
      * `name`: the entity name
      * `tags`: a column per `Tag`
    find [-o output_format] {tag[=value]|-tag}...
      List entities matching all the constraints.
      -o output_format
                  Use output_format as a Python format string to lay out
                  the listing.
                  Default: {entity.isodatetime} {headline}
    help [subcommand-names...]
      Print the help for the named subcommands,
      or for all subcommands if no names are specified.
    import [{-u|--update}] {-|srcpath}...
      Import CSV data in the format emitted by "export".
      Each argument is a file path or "-", indicating standard input.
      -u, --update  If a named entity already exists then update its tags.
                    Otherwise this will be seen as a conflict
                    and the import aborted.
    init
      Initialise the database.
      This includes defining the schema and making the root metanode.
    log [-c category,...] [-d when] [-D strptime] {-|headline} [tags...]
      Record entries into the database.
      If headline is '-', read headlines from standard input.
      -c categories
        Specify the categories for this log entry.
        The default is to recognise a leading CAT,CAT,...: prefix.
      -d when
        Use when, an ISO8601 date, as the log entry timestamp.
      -D strptime
        Read the time from the start of the headline
        according to the provided strptime specification.
    tag {-|entity-name} {tag[=value]|-tag}...
      Tag an entity with multiple tags.
      With the form "-tag", remove that tag from the direct tags.
      A entity-name named "-" indicates that entity-names should
      be read from the standard input.

BaseSQLTagsCommand.TAGSETS_CLASS

BaseSQLTagsCommand.TAGSET_CRITERION_CLASS

BaseSQLTagsCommand.TAG_BASED_TEST_CLASS

Method BaseSQLTagsCommand.apply_defaults(self)

Set up the default values in options.

Method BaseSQLTagsCommand.apply_opt(self, opt, val)

Apply a command line option.

Method BaseSQLTagsCommand.cmd_dbshell(self, argv)

Usage: {cmd} Start an interactive database shell.

Method BaseSQLTagsCommand.cmd_edit(self, argv)

Usage: edit criteria... Edit the entities specified by criteria.

Method BaseSQLTagsCommand.cmd_export(self, argv)

Usage: {cmd} {{tag[=value]|-tag}}... Export entities matching all the constraints. The output format is CSV data with the following columns:

• unixtime: the entity unixtime, a float
• id: the entity database row id, an integer
• name: the entity name
• tags: a column per Tag

Method BaseSQLTagsCommand.cmd_find(self, argv)

Usage: {cmd} [-o output_format] {{tag[=value]|-tag}}... List entities matching all the constraints. -o output_format Use output_format as a Python format string to lay out the listing. Default: {FIND_OUTPUT_FORMAT_DEFAULT}

Method BaseSQLTagsCommand.cmd_import(self, argv)

Usage: {cmd} [{{-u|--update}}] {{-|srcpath}}... Import CSV data in the format emitted by "export". Each argument is a file path or "-", indicating standard input. -u, --update If a named entity already exists then update its tags. Otherwise this will be seen as a conflict and the import aborted.

TODO: should this be a transaction so that an import is all or nothing?

Method BaseSQLTagsCommand.cmd_init(self, argv)

Usage: {cmd} Initialise the database. This includes defining the schema and making the root metanode.

Method BaseSQLTagsCommand.cmd_log(self, argv)

Record a log entry.

Usage: {cmd} [-c category,...] [-d when] [-D strptime] {{-|headline}} [tags...] Record entries into the database. If headline is '-', read headlines from standard input. -c categories Specify the categories for this log entry. The default is to recognise a leading CAT,CAT,...: prefix. -d when Use when, an ISO8601 date, as the log entry timestamp. -D strptime Read the time from the start of the headline according to the provided strptime specification.

Method BaseSQLTagsCommand.cmd_tag(self, argv)

Usage: {cmd} {{-|entity-name}} {{tag[=value]|-tag}}... Tag an entity with multiple tags. With the form "-tag", remove that tag from the direct tags. A entity-name named "-" indicates that entity-names should be read from the standard input.

Method BaseSQLTagsCommand.parse_tagset_criterion(arg, tag_based_test_class=None)

Parse tag criteria from argv.

The criteria may be either:

• an integer specifying a Tag id
• a sequence of tag criteria

Method BaseSQLTagsCommand.run_context(self)

Prepare the SQLTags around each command invocation.

Function glob2like(glob: str) -> str

Convert a filename glob to an SQL LIKE pattern.

Function main(argv=None)

Command line mode.

Function prefix2like(prefix: str, esc='\\') -> str

Convert a prefix string to an SQL LIKE pattern.

Class SQLParameters(SQLParameters,builtins.tuple)

The parameters required for constructing queries or extending queries with JOINs.

Attributes:

• criterion: the source criterion, usually an SQTCriterion subinstance
• alias: an alias of the source table for use in queries
• entity_id_column: the entities id column, alias.id if the alias is of entities, alias.entity_id if the alias is of tags
• constraint: a filter query based on alias

Class SQLTagBasedTest(cs.tagset.TagBasedTest,cs.tagset.TagBasedTest,builtins.tuple,SQTCriterion,cs.tagset.TagSetCriterion)

A cs.tagset.TagBasedTest extended with a .sql_parameters method.

Method SQLTagBasedTest.match_tagged_entity(self, te: cs.tagset.TagSet) -> bool

Match this criterion against te.

Class SQLTagProxies

A proxy for the tags supporting Python comparison => SQLParameters.

Example:

sqltags.tags.dotted.name.here == 'foo'

Class SQLTagProxy

An object based on a Tag name which produces an SQLParameters when compared with some value.

Example:

>>> sqltags = SQLTags('sqlite://')
>>> sqltags.init()
>>> # make a SQLParameters for testing the tag 'name.thing'==5
>>> sqlp = sqltags.tags.name.thing == 5
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.float_value = :float_value_1'
>>> sqlp = sqltags.tags.name.thing == 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value = :string_value_1'

Method SQLTagProxy.__eq__(self, other, alias=None) -> cs.sqltags.SQLParameters

Return an SQL = test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing == 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value = :string_value_1'

Method SQLTagProxy.__ge__(self, other)

Return an SQL >= test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing >= 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value >= :string_value_1'

Method SQLTagProxy.__getattr__(self, sub_tag_name)

Magic access to dotted tag names: produce a new SQLTagProxy from ourself.

Method SQLTagProxy.__gt__(self, other)

Return an SQL > test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing > 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value > :string_value_1'

Method SQLTagProxy.__le__(self, other)

Return an SQL <= test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing <= 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value <= :string_value_1'

Method SQLTagProxy.__lt__(self, other)

Return an SQL < test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing < 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value < :string_value_1'

Method SQLTagProxy.__ne__(self, other, alias=None) -> cs.sqltags.SQLParameters

Return an SQL <> test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing != 'foo'
>>> str(sqlp.constraint)
'tags_1.name = :name_1 AND tags_1.string_value != :string_value_1'

Method SQLTagProxy.by_op_text(self, op_text, other, alias=None)

Return an SQLParameters based on the comparison's text representation.

Parameters:

• op_text: the comparsion operation text, one of: '=', '<=', '<', '>=', '>', '~'.
• other: the other value for the comparison, used to infer the SQL column name and kept to provide the SQL value parameter
• alias: optional SQLAlchemy table alias

Method SQLTagProxy.likeglob(self, globptn: str) -> cs.sqltags.SQLParameters

Return an SQL LIKE test approximating a glob as an SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing.likeglob('foo*')
>>> str(sqlp.constraint)
"tags_1.name = :name_1 AND tags_1.string_value LIKE :string_value_1 ESCAPE '\\'"

Method SQLTagProxy.startswith(self, prefix: str) -> cs.sqltags.SQLParameters

Return an SQL LIKE prefix test SQLParameters.

Example:

>>> sqlp = SQLTags('sqlite://').tags.name.thing.startswith('foo')
>>> str(sqlp.constraint)
"tags_1.name = :name_1 AND tags_1.string_value LIKE :string_value_1 ESCAPE '\\'"

Class SQLTags(cs.tagset.TagSets,cs.resources.MultiOpenMixin)

A class using an SQL database to store its TagSets.

SQLTags.TagSetClass

Method SQLTags.__getitem__(self, *a, **kw)

Return an SQLTagSet for index (an int or str).

Method SQLTags.__setitem__(self, *a, **kw)

Dummy __setitem__ which checks te against the db by type because the factory inserts it into the database.

Method SQLTags.db_entity(self, index)

Return the Entities instance for index or None.

Method SQLTags.db_session(self, *, new=False, session=None)

Context manager to obtain a db session if required, just a shim for self.orm.session().

Property SQLTags.default_db_session

The current per-Thread SQLAlchemy Session.

Method SQLTags.default_factory(self, name: [<class 'str'>, None], *, unixtime=None, tags=None)

Fetch or create an SQLTagSet for name.

Note that name may be None to create a new "log" entry.

Method SQLTags.find(self, criteria)

Generate and run a query derived from criteria yielding SQLTagSet instances.

Parameters:

• criteria: an iterable of search criteria which should be SQTCriterions or a str suitable for SQTCriterion.from_str. A string may also be supplied, suitable for SQTCriterion.from_str.

Method SQLTags.flush(self)

Flush the current session state to the database.

Method SQLTags.get(self, index, default=None)

Return an SQLTagSet matching index, or None if there is no such entity.

Method SQLTags.import_csv_file(self, f, *, update_mode=False)

Import CSV data from the file f.

If update_mode is true named records which already exist will update from the data, otherwise the conflict will raise a ValueError.

Method SQLTags.import_tagged_entity(self, te, *, update_mode=False) -> None

Import the TagSet te.

This updates the database with the contents of the supplied TagSet, which has no inherent relationship to the database.

If update_mode is true named records which already exist will update from te, otherwise the conflict will raise a ValueError.

Method SQLTags.infer_db_url(envvar=None, default_path=None)

Infer the database URL.

Parameters:

• envvar: environment variable to specify a default, default from DBURL_ENVVAR (SQLTAGS_DBURL).

Method SQLTags.init(self)

Initialise the database.

Method SQLTags.items(self, *, prefix=None)

Return an iterable of (tagset_name,TagSet). Excludes unnamed TagSets.

Constrain the names to those starting with prefix if not None.

Method SQLTags.keys(self, *, prefix=None)

Yield all the nonNULL names.

Constrain the names to those starting with prefix if not None.

Property SQLTags.metanode

The metadata node.

Method SQLTags.values(self, *, prefix=None)

Return an iterable of the named TagSets. Excludes unnamed TagSets.

Constrain the names to those starting with prefix if not None.

Class SQLTagsCommand(BaseSQLTagsCommand,cs.cmdutils.BaseCommand,cs.tagset.TagsCommandMixin)

sqltags main command line utility.

Command line usage:

Usage: SQLTagsCommand [-f db_url] subcommand [...]
  -f db_url SQLAlchemy database URL or filename.
            Default from $SQLTAGS_DBURL (default '~/var/sqltags.sqlite').
  Subcommands:
    dbshell
      Start an interactive database shell.
    edit criteria...
      Edit the entities specified by criteria.
    export {tag[=value]|-tag}...
      Export entities matching all the constraints.
      The output format is CSV data with the following columns:
      * `unixtime`: the entity unixtime, a float
      * `id`: the entity database row id, an integer
      * `name`: the entity name
      * `tags`: a column per `Tag`
    find [-o output_format] {tag[=value]|-tag}...
      List entities matching all the constraints.
      -o output_format
                  Use output_format as a Python format string to lay out
                  the listing.
                  Default: {entity.isodatetime} {headline}
    help [subcommand-names...]
      Print the help for the named subcommands,
      or for all subcommands if no names are specified.
    import [{-u|--update}] {-|srcpath}...
      Import CSV data in the format emitted by "export".
      Each argument is a file path or "-", indicating standard input.
      -u, --update  If a named entity already exists then update its tags.
                    Otherwise this will be seen as a conflict
                    and the import aborted.
    init
      Initialise the database.
      This includes defining the schema and making the root metanode.
    log [-c category,...] [-d when] [-D strptime] {-|headline} [tags...]
      Record entries into the database.
      If headline is '-', read headlines from standard input.
      -c categories
        Specify the categories for this log entry.
        The default is to recognise a leading CAT,CAT,...: prefix.
      -d when
        Use when, an ISO8601 date, as the log entry timestamp.
      -D strptime
        Read the time from the start of the headline
        according to the provided strptime specification.
    ns entity-names...
      List entities and their tags.
    tag {-|entity-name} {tag[=value]|-tag}...
      Tag an entity with multiple tags.
      With the form "-tag", remove that tag from the direct tags.
      A entity-name named "-" indicates that entity-names should
      be read from the standard input.

Method SQLTagsCommand.cmd_ns(self, argv)

Usage: {cmd} entity-names... List entities and their tags.

Class SQLTagSet(cs.obj.SingletonMixin,cs.tagset.TagSet,builtins.dict,cs.lex.FormatableMixin,cs.mappings.AttrableMappingMixin)

A singleton TagSet attached to an SQLTags instance.

Method SQLTagSet.add_db_tag(self, *a, **kw)

Add a tag to the database.

Method SQLTagSet.child_tagsets(self, tag_name='parent')

Return the child TagSets as defined by their parent Tag, by default the Tag named 'parent'.

Method SQLTagSet.db_session(self, *, session=None)

Context manager to obtain a new session if required, just a shim for self.sqltags.db_session.

Method SQLTagSet.discard(self, name, value=None, *a, **kw)

pylint: disable=keyword-arg-before-vararg

Method SQLTagSet.discard_db_tag(self, tag_name, value=None)

Discard a tag from the database.

Property SQLTagSet.name

Return the .name.

Method SQLTagSet.parent_tagset(self, tag_name='parent')

Return the parent TagSet as defined by a Tag, by default the Tag named 'parent'.

Method SQLTagSet.set(self, name, value=None, *a, **kw)

pylint: disable=keyword-arg-before-vararg

Class SQLTagsORM(cs.sqlalchemy_utils.ORM,cs.resources.MultiOpenMixin,cs.dateutils.UNIXTimeMixin)

The ORM for an SQLTags.

Method SQLTagsORM.declare_schema(self)

Define the database schema / ORM mapping.

Method SQLTagsORM.define_schema(self)

Instantiate the schema and define the root metanode.

Method SQLTagsORM.prepare_metanode(self, *, session)

Ensure row id 0, the metanode, exists.

Method SQLTagsORM.search(self, *a, **kw)

Construct a query to match Entity rows matching the supplied criteria iterable. Return an SQLAlchemy Query.

The mode parameter has the following values:

• 'id': the query only yields entity ids
• 'entity': (default) the query yields entities without tags
• 'tagged': (default) the query yields entities left outer joined with their matching tags

Note that the 'tagged' result produces multiple rows for any entity with multiple tags, and that this requires the caller to fold entities with multiple tags together.

Note: due to implementation limitations the SQL query itself may not apply all the criteria, so every criterion must still be applied to the results using its .match_entity method.

If name is omitted or None the query will match log entities otherwise the entity with the specified name.

The criteria should be an iterable of SQTCriterion instances used to construct the query.

Class SQTCriterion(cs.tagset.TagSetCriterion)

Subclass of TagSetCriterion requiring an .sql_parameters method which returns an SQLParameters providing the information required to construct an sqlalchemy query. It also resets .CRITERION_PARSE_CLASSES, which will pick up the SQL capable criterion classes below.

SQTCriterion.TAG_BASED_TEST_CLASS

Method SQTCriterion.match_tagged_entity(self, te: cs.tagset.TagSet) -> bool

Perform the criterion test on the Python object directly. This is used at the end of a query to implement tests which cannot be sufficiently implemented in SQL. If self.SQL_COMPLETE it is not necessary to call this method.

Method SQTCriterion.sql_parameters(self, orm) -> cs.sqltags.SQLParameters

Subclasses must return am SQLParameters instance parameterising the SQL queries that follow.

Class SQTEntityIdTest(SQTCriterion,cs.tagset.TagSetCriterion)

A test on entity.id.

Method SQTEntityIdTest.match_tagged_entity(self, te: cs.tagset.TagSet) -> bool

Test the TagSet te against self.entity_ids.

Method SQTEntityIdTest.parse(s, offset=0, delim=None)

Parse a decimal entity id from s.

Function verbose(msg, *a)

Emit message if in verbose mode.

Release Log

Release 20210404:

• SQLTags.getitem: when autocreating an entity, do it in a new session so that the entity is commited to the database before any further use.
• SQLTagsCommand: new cmd_dbshell to drop you into the database.

Release 20210321: Drop logic now merged with cs.sqlalchemy_utils, use the new default session stuff.

Release 20210306.1: Docstring updates.

Release 20210306: Initial release.