Hide keyboard shortcuts

Hot-keys on this page

r m x p   toggle line displays

j k   next/prev highlighted chunk

0   (zero) top of page

1   (one) first highlighted chunk

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

# This file is part of daf_butler. 

# 

# Developed for the LSST Data Management System. 

# This product includes software developed by the LSST Project 

# (http://www.lsst.org). 

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

# for details of code ownership. 

# 

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

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

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

# (at your option) any later version. 

# 

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

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

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

# GNU General Public License for more details. 

# 

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

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

 

import os.path 

 

from lsst.utils import doImport 

from lsst.daf.butler.formatters.fileFormatter import FileFormatter 

 

__all__ = ("PexConfigFormatter", ) 

 

 

class PexConfigFormatter(FileFormatter): 

"""Interface for reading and writing pex.config.Config objects from disk. 

""" 

extension = ".py" 

 

def _readFile(self, path, pytype): 

"""Read a pex.config.Config instance from the given file. 

 

Parameters 

---------- 

path : `str` 

Path to use to open the file. 

pytype : `class` 

Class to use to read the config file. 

 

Returns 

------- 

data : `lsst.pex.config.Config` 

Instance of class `pytype` read from config file. None 

if the file could not be opened. 

""" 

if not os.path.exists(path): 

return None 

instance = pytype() 

# Configs can only be loaded if you use the correct derived type, 

# but we can't really store the correct derive type in the StorageClass 

# because that"d be a huge proliferation of StorageClasses. 

# Instead, we use a bit of a hack: try to load using the base-class 

# Config, inspect the exception message to obtain the class we should 

# have used, import that, and try it instead. 

# TODO: clean this up, somehow. 

try: 

instance.load(path) 

return instance 

except AssertionError as err: 

msg = str(err) 

if not msg.startswith("config is of type"): 

raise RuntimeError("Unexpected assertion; cannot infer Config class type.") from err 

actualPyTypeStr = msg.split()[-1] 

actualPyType = doImport(actualPyTypeStr) 

instance = actualPyType() 

instance.load(path) 

return instance 

 

def _writeFile(self, inMemoryDataset, fileDescriptor): 

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

 

Parameters 

---------- 

inMemoryDataset : `object` 

Object to serialize. 

fileDescriptor : `FileDescriptor` 

Details of the file to be written. 

 

Raises 

------ 

Exception 

The file could not be written. 

""" 

inMemoryDataset.save(fileDescriptor.location.path)