Coverage for python/lsst/daf/butler/formatters/packages.py: 62%

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1# This file is part of daf_butler. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This software is dual licensed under the GNU General Public License and also 

10# under a 3-clause BSD license. Recipients may choose which of these licenses 

11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt, 

12# respectively. If you choose the GPL option then the following text applies 

13# (but note that there is still no warranty even if you opt for BSD instead): 

14# 

15# This program is free software: you can redistribute it and/or modify 

16# it under the terms of the GNU General Public License as published by 

17# the Free Software Foundation, either version 3 of the License, or 

18# (at your option) any later version. 

19# 

20# This program is distributed in the hope that it will be useful, 

21# but WITHOUT ANY WARRANTY; without even the implied warranty of 

22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

23# GNU General Public License for more details. 

24# 

25# You should have received a copy of the GNU General Public License 

26# along with this program. If not, see <http://www.gnu.org/licenses/>. 

27 

28__all__ = ("PackagesFormatter",) 

29 

30import os.path 

31from typing import Any 

32 

33from lsst.daf.butler.formatters.file import FileFormatter 

34from lsst.utils.packages import Packages 

35 

36 

37class PackagesFormatter(FileFormatter): 

38 """Interface for reading and writing `~lsst.utils.packages.Packages`. 

39 

40 This formatter supports write parameters: 

41 

42 * ``format``: The file format to use to write the package data. Allowed 

43 options are ``yaml``, ``json``, and ``pickle``. 

44 """ 

45 

46 supportedWriteParameters = frozenset({"format"}) 

47 supportedExtensions = frozenset({".yaml", ".pickle", ".pkl", ".json"}) 

48 

49 # MyPy does't like the fact that the base declares this an instance 

50 # attribute while this derived class uses a property. 

51 @property 

52 def extension(self) -> str: # type: ignore 

53 # Default to YAML but allow configuration via write parameter 

54 format = self.writeParameters.get("format", "yaml") 

55 ext = "." + format 

56 if ext not in self.supportedExtensions: 56 ↛ 57line 56 didn't jump to line 57, because the condition on line 56 was never true

57 raise RuntimeError(f"Requested file format '{format}' is not supported for Packages") 

58 return ext 

59 

60 def _readFile(self, path: str, pytype: type | None = None) -> Any: 

61 """Read a file from the path. 

62 

63 Parameters 

64 ---------- 

65 path : `str` 

66 Path to use to open the file. 

67 pytype : `type` 

68 Class to use to read the serialized file. 

69 

70 Returns 

71 ------- 

72 data : `object` 

73 Instance of class ``pytype`` read from serialized file. None 

74 if the file could not be opened. 

75 """ 

76 if not os.path.exists(path): 

77 return None 

78 

79 assert pytype is not None 

80 assert issubclass(pytype, Packages) 

81 return pytype.read(path) 

82 

83 def _fromBytes(self, serializedDataset: Any, pytype: type | None = None) -> Any: 

84 """Read the bytes object as a python object. 

85 

86 Parameters 

87 ---------- 

88 serializedDataset : `bytes` 

89 Bytes object to unserialize. 

90 pytype : `type` 

91 The Python type to be instantiated. Required. 

92 

93 Returns 

94 ------- 

95 inMemoryDataset : `object` 

96 The requested data as an object, or None if the string could 

97 not be read. 

98 """ 

99 # The format can not come from the formatter configuration 

100 # because the current configuration has no connection to how 

101 # the data were stored. 

102 if serializedDataset.startswith(b"!<lsst."): 102 ↛ 104line 102 didn't jump to line 104, because the condition on line 102 was never false

103 format = "yaml" 

104 elif serializedDataset.startswith(b'{"'): 

105 format = "json" 

106 else: 

107 format = "pickle" 

108 

109 assert pytype is not None 

110 assert issubclass(pytype, Packages) 

111 return pytype.fromBytes(serializedDataset, format) 

112 

113 def _writeFile(self, inMemoryDataset: Any) -> None: 

114 """Write the in memory dataset to file on disk. 

115 

116 Parameters 

117 ---------- 

118 inMemoryDataset : `object` 

119 Object to serialize. 

120 

121 Raises 

122 ------ 

123 Exception 

124 The file could not be written. 

125 """ 

126 inMemoryDataset.write(self.fileDescriptor.location.path) 

127 

128 def _toBytes(self, inMemoryDataset: Any) -> bytes: 

129 """Write the in memory dataset to a bytestring. 

130 

131 Parameters 

132 ---------- 

133 inMemoryDataset : `object` 

134 Object to serialize 

135 

136 Returns 

137 ------- 

138 serializedDataset : `bytes` 

139 YAML string encoded to bytes. 

140 

141 Raises 

142 ------ 

143 Exception 

144 The object could not be serialized. 

145 """ 

146 format = self.extension.lstrip(".") 

147 return inMemoryDataset.toBytes(format)