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# -*- coding: utf-8 -*-
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
"""
Outputter to generate Swift code for metrics.
"""
import enum
import json
from pathlib import Path
from typing import Any, Dict, Optional, Union
from . import __version__
from . import metrics
from . import pings
from . import tags
from . import util
# An (imcomplete) list of reserved keywords in Swift.
# These will be replaced in generated code by their escaped form.
SWIFT_RESERVED_NAMES = ["internal", "typealias"]
def swift_datatypes_filter(value: util.JSONType) -> str:
"""
A Jinja2 filter that renders Swift literals.
Based on Python's JSONEncoder, but overrides:
- dicts to use `[key: value]`
- sets to use `[...]`
- enums to use the like-named Swift enum
- Rate objects to a CommonMetricData initializer
(for external Denominators' Numerators lists)
"""
class SwiftEncoder(json.JSONEncoder):
def iterencode(self, value):
if isinstance(value, dict):
yield "["
first = True
for key, subvalue in value.items():
if not first:
yield ", "
yield from self.iterencode(key)
yield ": "
yield from self.iterencode(subvalue)
first = False
yield "]"
elif isinstance(value, enum.Enum):
yield ("." + util.camelize(value.name))
elif isinstance(value, list):
yield "["
first = True
for subvalue in value:
if not first:
yield ", "
yield from self.iterencode(subvalue)
first = False
yield "]"
elif isinstance(value, set):
yield "["
first = True
for subvalue in sorted(list(value)):
if not first:
yield ", "
yield from self.iterencode(subvalue)
first = False
yield "]"
elif value is None:
yield "nil"
elif isinstance(value, metrics.Rate):
yield "CommonMetricData("
first = True
for arg_name in util.common_metric_args:
if hasattr(value, arg_name):
if not first:
yield ", "
yield f"{util.camelize(arg_name)}: "
yield from self.iterencode(getattr(value, arg_name))
first = False
yield ")"
else:
yield from super().iterencode(value)
return "".join(SwiftEncoder().iterencode(value))
def type_name(obj: Union[metrics.Metric, pings.Ping]) -> str:
"""
Returns the Swift type to use for a given metric or ping object.
"""
generate_enums = getattr(obj, "_generate_enums", [])
if len(generate_enums):
generic = None
for member, suffix in generate_enums:
if len(getattr(obj, member)):
generic = util.Camelize(obj.name) + suffix
else:
if isinstance(obj, metrics.Event):
generic = "NoExtras"
else:
generic = "No" + suffix
return "{}<{}>".format(class_name(obj.type), generic)
generate_structure = getattr(obj, "_generate_structure", [])
if len(generate_structure):
generic = util.Camelize(obj.name) + "Object"
return "{}<{}>".format(class_name(obj.type), generic)
return class_name(obj.type)
def extra_type_name(typ: str) -> str:
"""
Returns the corresponding Swift type for event's extra key types.
"""
if typ == "boolean":
return "Bool"
elif typ == "string":
return "String"
elif typ == "quantity":
return "Int32"
else:
return "UNSUPPORTED"
def structure_type_name(typ: str) -> str:
"""
Returns the corresponding Swift type for structure items.
"""
if typ == "boolean":
return "Bool"
elif typ == "string":
return "String"
elif typ == "number":
return "Int64"
else:
return "UNSUPPORTED"
def class_name(obj_type: str) -> str:
"""
Returns the Swift class name for a given metric or ping type.
"""
if obj_type == "ping":
return "Ping"
if obj_type.startswith("labeled_"):
obj_type = obj_type[8:]
return util.Camelize(obj_type) + "MetricType"
def variable_name(var: str) -> str:
"""
Returns a valid Swift variable name, escaping keywords if necessary.
"""
if var in SWIFT_RESERVED_NAMES:
return "`" + var + "`"
else:
return var
class BuildInfo:
def __init__(self, build_date):
self.build_date = build_date
def generate_build_date(date: Optional[str]) -> str:
"""
Generate the build timestamp.
"""
ts = util.build_date(date)
data = [
("year", ts.year),
("month", ts.month),
("day", ts.day),
("hour", ts.hour),
("minute", ts.minute),
("second", ts.second),
]
# The internal DatetimeMetricType API can take a `DateComponents` object,
# which lets us easily specify the timezone.
components = ", ".join([f"{name}: {val}" for (name, val) in data])
return f'DateComponents(calendar: Calendar.current, timeZone: TimeZone(abbreviation: "UTC"), {components})' # noqa
class Category:
"""
Data struct holding information about a metric to be used in the template.
"""
name: str
objs: Dict[str, Union[metrics.Metric, pings.Ping, tags.Tag]]
contains_pings: bool
def output_swift(
objs: metrics.ObjectTree, output_dir: Path, options: Optional[Dict[str, Any]] = None
) -> None:
"""
Given a tree of objects, output Swift code to `output_dir`.
:param objects: A tree of objects (metrics and pings) as returned from
`parser.parse_objects`.
:param output_dir: Path to an output directory to write to.
:param options: options dictionary, with the following optional keys:
- namespace: The namespace to generate metrics in
- glean_namespace: The namespace to import Glean from
- allow_reserved: When True, this is a Glean-internal build
- with_buildinfo: If "true" the `GleanBuildInfo` is generated.
Otherwise generation of that file is skipped.
Defaults to "true".
- build_date: If set to `0` a static unix epoch time will be used.
If set to a ISO8601 datetime string (e.g. `2022-01-03T17:30:00`)
it will use that date.
Other values will throw an error.
If not set it will use the current date & time.
"""
if options is None:
options = {}
template = util.get_jinja2_template(
"swift.jinja2",
filters=(
("swift", swift_datatypes_filter),
("type_name", type_name),
("class_name", class_name),
("variable_name", variable_name),
("extra_type_name", extra_type_name),
("structure_type_name", structure_type_name),
),
)
namespace = options.get("namespace", "GleanMetrics")
glean_namespace = options.get("glean_namespace", "Glean")
with_buildinfo = options.get("with_buildinfo", "true").lower() == "true"
build_date = options.get("build_date", None)
build_info = None
if with_buildinfo:
build_date = generate_build_date(build_date)
build_info = BuildInfo(build_date=build_date)
filename = "Metrics.swift"
filepath = output_dir / filename
categories = []
for category_key, category_val in objs.items():
contains_pings = any(
isinstance(obj, pings.Ping) for obj in category_val.values()
)
cat = Category()
cat.name = category_key
cat.objs = category_val
cat.contains_pings = contains_pings
categories.append(cat)
with filepath.open("w", encoding="utf-8") as fd:
fd.write(
template.render(
parser_version=__version__,
categories=categories,
common_metric_args=util.common_metric_args,
extra_metric_args=util.extra_metric_args,
namespace=namespace,
glean_namespace=glean_namespace,
allow_reserved=options.get("allow_reserved", False),
build_info=build_info,
)
)
# Jinja2 squashes the final newline, so we explicitly add it
fd.write("\n")