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Add utility support wrapping CrateDB's special table options #143

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1 change: 1 addition & 0 deletions CHANGES.md
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Expand Up @@ -2,6 +2,7 @@


## Unreleased
- Added utility support wrapping CrateDB's special table options

## 2024/06/25 0.38.0
- Added/reactivated documentation as `sqlalchemy-cratedb`
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2 changes: 2 additions & 0 deletions src/sqlalchemy_cratedb/support/__init__.py
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@@ -1,3 +1,4 @@
from sqlalchemy_cratedb.support.model import TableOptions
from sqlalchemy_cratedb.support.pandas import insert_bulk, table_kwargs
from sqlalchemy_cratedb.support.polyfill import check_uniqueness_factory, refresh_after_dml, \
patch_autoincrement_timestamp
Expand All @@ -11,4 +12,5 @@
refresh_dirty,
refresh_table,
table_kwargs,
TableOptions,
]
336 changes: 336 additions & 0 deletions src/sqlalchemy_cratedb/support/model.py
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import dataclasses
import typing as t
from collections import OrderedDict
from urllib.parse import urlparse, parse_qs, parse_qsl

Check notice

Code scanning / CodeQL

Unused import Note

Import of 'parse_qs' is not used.

from sqlalchemy.util import asbool


@dataclasses.dataclass
class TableOptionSpec:
name: str
type: t.Optional[str] = None
default: t.Optional[t.Any] = None
choices: t.Optional[list] = None
translate: t.Optional[t.Dict[str, str]] = None
unit: t.Optional[str] = None
description: t.Optional[str] = None
docs: t.Optional[str] = None


class TableOptions(dict):
"""
Manage a dictionary of SQLAlchemy dialect options in `<dialect>_<option> = <value>` format.

References:
- https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#with
- https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-translog.html
"""

# Map shorthand URL parameters to CrateDB's first-level special SQLAlchemy table options.
URL_PARAM_SA_OPTIONS_MAP: t.Dict[str, TableOptionSpec] = {
# Cluster options.
"clustered-by": TableOptionSpec(name="crate_clustered_by"),
"partitioned-by": TableOptionSpec(name="crate_partitioned_by"),
"shards": TableOptionSpec(name="crate_number_of_shards", type="int", default=4),
# Table options.
"async-flush-interval": TableOptionSpec(
name='crate_"translog.sync_interval"',
type="int",
unit="ms",
default=5000,
description="Transaction log flushing interval when using `durability=async`.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#translog-sync-interval",
),
"async-flush-size": TableOptionSpec(
name='crate_"translog.flush_threshold_size"',
type="str",
unit="bytes",
default="512Mb",
description="Transaction log flushing threshold size when using `durability=async`.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#translog-flush-threshold-size",
),
"column-policy": TableOptionSpec(
name="crate_column_policy",
type="str",
choices=["strict", "dynamic"],
default="strict",
description="The column policy of the table. "
"`strict` will reject any column which is not defined in the schema. "
"`dynamic` means that new columns can be added on demand.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#column-policy",
),
"compression": TableOptionSpec(
name="crate_codec",
type="str",
choices=["lz4", "deflate"],
default="lz4",
description="By default, data is stored using LZ4 compression. This can be changed "
"to `best_compression` which uses DEFLATE for a higher compression ratio, "
"at the expense of slower column value lookups..",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#codec",
translate={
"lz4": "default",
"deflate": "best_compression",
},
),
"disable-read": TableOptionSpec(
name='crate_"blocks.read"',
type="bool",
default=False,
description="Set to `true` to disable all read operations for a table.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#blocks-read",
),
"disable-metadata": TableOptionSpec(
name='crate_"blocks.metadata"',
type="bool",
default=False,
description="Set to `true` to disable modifications on table settings.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#blocks-metadata",
),
"disable-write": TableOptionSpec(
name='crate_"blocks.write"',
type="bool",
default=False,
description="Set to `true` to disable all write operations for a table.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#blocks-write",
),
"durability": TableOptionSpec(
name='crate_"translog.durability"',
type="str",
choices=["request", "async"],
default="request",
description="If set to `request`, the transaction log will be flushed after every write operation. "
"If set to `async`, the transaction log gets flushed to disk periodically in the background. ",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#translog-durability",
),
"max-fields": TableOptionSpec(
name='crate_"mapping.total_fields.limit"',
type="int",
default=1000,
description="Maximum number of columns that is allowed for a table, "
"including both the user facing mapping (columns) and internal fields.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#mapping-total-fields-limit",
),
"max-ngram-diff": TableOptionSpec(
name="crate_max_ngram_diff",
type="int",
default=1,
description="Maximum difference between `max_ngram` and `min_ngram` when using the `NGramTokenizer` or the `NGramTokenFilter`.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#max-ngram-diff",
),
"max-merge-threads": TableOptionSpec(
name='crate_"merge.scheduler.max_thread_count"',
type="int",
description="Maximum number of threads on a single shard that may be merging at once. "
"The default will be auto-configured based on the number of CPU cores, "
"optimized for a good solid-state-disk (SSD). On spinning drives, decrease "
"this to 1.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#merge-scheduler-max-thread-count",
),
"max-shingle-diff": TableOptionSpec(
name="crate_max_shingle_diff",
type="int",
default=3,
description="Maximum difference between `min_shingle_size` and `"
"max_shingle_size` when using the `ShingleTokenFilter`.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#max-shingle-diff",
),
"min-shards-write": TableOptionSpec(
name='crate_"write.wait_for_active_shards"',
type="str",
default="1",
description="Number of shard copies that need to be active for write operations to proceed.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#write-wait-for-active-shards",
),
"read-only": TableOptionSpec(
name='crate_"blocks.read_only"',
type="bool",
default=False,
description="Table is read only if value set to `true`. "
"Allows writes and table settings changes if set to `false`.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#blocks-read-only",
),
"read-only-allow-delete": TableOptionSpec(
name='crate_"blocks.read_only_allow_delete"',
type="bool",
default=False,
description="Allows to have a read only table that additionally can be deleted.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#blocks-read-only-allow-delete",
),
"refresh-interval": TableOptionSpec(
name="crate_refresh_interval",
type="int",
unit="ms",
default=1000,
description="Interval for table-level automatic background refresh.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#refresh-interval",
),
"replicas": TableOptionSpec(
name="crate_number_of_replicas",
type="str",
default="0-1",
description="The number or range of replicas each shard of a table should have for normal operation",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#number-of-replicas",
),
"routing-shards": TableOptionSpec(
name="crate_number_of_routing_shards",
type="int",
# TODO: Which default value does this have?
description="The hashing space that is used internally to distribute documents across shards.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#number-of-routing-shards",
),
"routing-max-shards-per-node": TableOptionSpec(
name='crate_"routing.allocation.total_shards_per_node"',
type="int",
default=-1,
description="Control the total number of shards (replicas and primaries) "
"allowed to be allocated on a single node. The default is unbounded.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#routing-allocation-total-shards-per-node",
),
"routing-policy": TableOptionSpec(
name='crate_"routing.allocation.enable"',
type="str",
choices=["all", "primaries", "new_primaries", "none"],
default="all",
description="Control shard allocation for a specific table.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#routing-allocation-enable",
),
"routing-max-retries": TableOptionSpec(
name='crate_"allocation.max_retries"',
type="int",
default=5,
description="Attempts to allocate a shard before giving up and leaving the shard unallocated.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#allocation-max-retries",
),
"routing-include": TableOptionSpec(
name='crate_"routing.allocation.include.{attribute}"',
type="str",
description="Assign the table to a node whose `{attribute} has at least one of the comma-separated values.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#routing-allocation-include-attribute",
),
"routing-require": TableOptionSpec(
name='crate_"routing.allocation.require.{attribute}"',
type="str",
description="Assign the table to a node whose `{attribute} has all of the comma-separated values.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#routing-allocation-require-attribute",
),
"routing-exclude": TableOptionSpec(
name='crate_"routing.allocation.exclude.{attribute}"',
type="str",
description="Assign the table to a node whose `{attribute} has none of the comma-separated values.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#routing-allocation-exclude-attribute",
),
"shard-unassigned-reallocate-delay": TableOptionSpec(
name='crate_"unassigned.node_left.delayed_timeout"',
type="str",
default="1m",
description="Delay the allocation of replica shards which have become unassigned because a node has left.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#unassigned-node-left-delayed-timeout",
),
"soft-deletes-enable": TableOptionSpec(
name='crate_"soft_deletes.enabled"',
type="bool",
default=True,
description="Whether soft deletes are enabled or disabled.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#soft-deletes-enabled",
),
"soft-deletes-retention-period": TableOptionSpec(
name='crate_"soft_deletes.retention_lease.period"',
type="str",
default="12h",
description="The maximum period for which a retention lease is retained before it is considered expired.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#soft-deletes-retention-lease-period",
),
"store-type": TableOptionSpec(
name='crate_"store.type"',
type="str",
choices=["fs", "niofs", "mmapfs", "hybridfs"],
default="fs",
description="Control how data is stored and accessed on disk. It's not possible to update this setting after table creation.",
docs="https://cratedb.com/docs/crate/reference/en/latest/sql/statements/create-table.html#store-type",
),
}

# List of option name prefixes for second-level table options.
URL_PARAM_SA_OPTIONS_PREFIXES = [
"allocation.",
"blocks.",
"codec",
"mapping.",
"merge.",
"routing.",
"soft_deletes.",
"store.",
"translog.",
"unassigned.",
"write.",
]

@classmethod
def from_url(cls, url: t.Any):
"""
Factory for creating a DialectOptions object from a URL object.
"""

# Support for plain strings.
if isinstance(url, str):
url = urlparse(url)
query_params = dict(parse_qsl(url.query))

# Support for boltons.urlutils, as used by CrateDB Toolkit.
elif hasattr(url, "query_params"):
query_params = url.query_params

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else:
raise TypeError(f"URL data type unsupported: {type(url)}")

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return cls.from_query_params(query_params=query_params)

@classmethod
def from_query_params(cls, query_params: t.Dict[str, str]):
"""
Convert from shorthand URL parameter notation into a dictionary of SQLAlchemy dialect options.

The output item format is `<dialect>_<option> = <value>`.
"""
options = OrderedDict()

# Process options having explicit mapping rules.
for query_name, spec in cls.URL_PARAM_SA_OPTIONS_MAP.items():
if query_name in query_params:
options[spec.name] = cls.convert_value(query_params[query_name], spec)

# Process options without explicit rules.
for query_name_prefix in cls.URL_PARAM_SA_OPTIONS_PREFIXES:
for param, value in query_params.items():
key = f'crate_"{param}"'
if param.startswith(query_name_prefix) and key not in options:
options[key] = value

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return cls(**options)

@staticmethod
def convert_value(value: t.Any, spec: TableOptionSpec) -> t.Union[str, int, None]:
"""
Convert option value into the right format, based on its specification.
"""
print("value:", value)
if type_ := spec.type:
if type_ == "str":
value = value.strip("'")
elif type_ == "int":
value = value.strip("'")
value = int(value)
elif type_ == "bool":
value = value.strip("'")
value = asbool(value)
if spec.choices:
if value not in spec.choices:
raise ValueError(f"Value {value} not permitted. Allowed choices: {spec.choices}")

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if spec.translate:
value = spec.translate.get(value, value)
if type_ == "str":
value = f"'{value}'"
elif type_ == "bool":
value = str(value).lower()
return value
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