[MRG] implement a simple ZipFileLinearIndex class

doc/command-line.md

@@ -842,7 +842,9 @@ scaled values will be made compatible.
 ### Storing (and searching) signatures
 
 Backing up a little, there are many ways to store and search
-signatures.
+signatures. sourmash supports storing and loading signatures from JSON
+files, directories, lists of files, Zip files, and indexed databases.
+These can all be used interchangeably for sourmash operations.
 
 The simplest is one signature in a single JSON file. You can also put
 many signatures in a single JSON file, either by building them that
@@ -851,7 +853,29 @@ commands. Searching or comparing these files involves loading them
 sequentially and iterating across all of the signatures - which can be
 slow, especially for many (100s or 1000s) of signatures.
 
-Indexed databases can make searching signatures a lot faster. SBT
+### Zip files
+
+All of the `sourmash` commands support loading collections of
+signatures from zip files.  You can create a compressed collection of
+signatures using `zip -r collection.zip *.sig` and then specify
+`collections.zip` on the command line.
+
+### Loading all signatures under a directory
+
+All of the `sourmash` commands support loading signatures from
+beneath directories; provide the paths on the command line.
+
+#### Passing in lists of files
+
+Most sourmash commands will also take `--from-file` or
+`--query-from-file`, which will take a path to a text file containing
+a list of file paths. This can be useful for situations where you want
+to specify thousands of queries, or a subset of signatures produced by
+some other command.
+
+#### Indexed databases
+
+Indexed databases can make searching signatures much faster. SBT
 databases are low memory and disk-intensive databases that allow for
 fast searches using a tree structure, while LCA databases are higher
 memory and (after a potentially significant load time) are quite fast.
@@ -869,19 +893,6 @@ will complain. In contrast, signature files can
 contain many different types of signatures, and compatible ones will
 be discovered automatically.
 
-### Passing in lists of files
-
-Various sourmash commands will also take `--from-file` or
-`--query-from-file`, which will take a path to a text file containing
-a list of file paths. This can be useful for situations where you want
-to specify thousands of queries, or a subset of signatures produced by
-some other command.
-
-### Loading all signatures under a directory
-
-All of the `sourmash` commands support loading signatures from
-beneath directories; provide the paths on the command line.
-
 ### Combining search databases on the command line
 
 All of the commands in sourmash operate in "online" mode, so you can
@@ -902,9 +913,9 @@ been useful. :)
 
 ### Using stdin
 
-Most commands will take stdin via the usual UNIX convention, `-`.
-Moreover, `sourmash sketch` and the `sourmash sig` commands will
-output to stdout.  So, for example,
+Most commands will take signature JSON data via stdin using the usual
+UNIX convention, `-`.  Moreover, `sourmash sketch` and the `sourmash
+sig` commands will output to stdout.  So, for example,
 
 `sourmash sketch ... -o - | sourmash sig describe -` will describe the
 signatures that were just created.

src/sourmash/index.py

@@ -3,6 +3,7 @@
 import sourmash
 from abc import abstractmethod, ABC
 from collections import namedtuple
+import zipfile
 import os
 
 
@@ -83,7 +84,7 @@ def search(self, query, threshold=None,
         for ss in self.signatures():
             score = query_match(ss)
             if score >= threshold:
-                matches.append((score, ss, self.filename))
+                matches.append((score, ss, self.location))
 
         # sort!
         matches.sort(key=lambda x: -x[0])
@@ -119,7 +120,7 @@ def gather(self, query, *args, **kwargs):
         for ss in self.signatures():
             cont = query.minhash.contained_by(ss.minhash, True)
             if cont and cont >= threshold:
-                results.append((cont, ss, self.filename))
+                results.append((cont, ss, self.location))
 
         results.sort(reverse=True, key=lambda x: (x[0], x[1].md5sum()))
 
@@ -182,7 +183,7 @@ def __init__(self, _signatures=None, filename=None):
         self._signatures = []
         if _signatures:
             self._signatures = list(_signatures)
-        self.filename = filename
+        self.location = filename
 
     def signatures(self):
         return iter(self._signatures)
@@ -219,7 +220,66 @@ def select(self, **kwargs):
             if select_signature(ss, **kwargs):
                 siglist.append(ss)
 
-        return LinearIndex(siglist, self.filename)
+        return LinearIndex(siglist, self.location)
+
+
+class ZipFileLinearIndex(Index):
+    """\
+    A read-only collection of signatures in a zip file.
+
+    Does not support `insert` or `save`.
+    """
+    is_database = True
+
+    def __init__(self, zf, selection_dict=None,
+                 traverse_yield_all=False):
+        self.zf = zf
+        self.selection_dict = selection_dict
+        self.traverse_yield_all = traverse_yield_all
+
+    def __len__(self):
+        return len(list(self.signatures()))
+
+    @property
+    def location(self):
+        return self.zf.filename
+
+    def insert(self, signature):
+        raise NotImplementedError
+
+    def save(self, path):
+        raise NotImplementedError
+
+    @classmethod
+    def load(cls, location, traverse_yield_all=False):
+        "Class method to load a zipfile."
+        zf = zipfile.ZipFile(location, 'r')
+        return cls(zf, traverse_yield_all=traverse_yield_all)
+
+    def signatures(self):
+        "Load all signatures in the zip file."
+        from .signature import load_signatures
+        for zipinfo in self.zf.infolist():
+            # should we load this file? if it ends in .sig OR we are forcing:
+            if zipinfo.filename.endswith('.sig') or \
+               zipinfo.filename.endswith('.sig.gz') or \
+               self.traverse_yield_all:
+                fp = self.zf.open(zipinfo)
+
+                # now load all the signatures and select on ksize/moltype:
+                selection_dict = self.selection_dict
+                for ss in load_signatures(fp):
+                    if selection_dict:
+                        if select_signature(ss, **self.selection_dict):
+                            yield ss
+                    else:
+                        yield ss
+
+    def select(self, **kwargs):
+        "Select signatures in zip file based on ksize/moltype/etc."
+        return ZipFileLinearIndex(self.zf,
+                                  selection_dict=kwargs,
+                                  traverse_yield_all=self.traverse_yield_all)
 
 
 class MultiIndex(Index):

src/sourmash/sbt.py

@@ -754,9 +754,7 @@ def load(cls, location, *, leaf_loader=None, storage=None, print_version_warning
 
             if storage:
                 sbts = storage.list_sbts()
-                if len(sbts) != 1:
-                    print("no SBT, or too many SBTs!")
-                else:
+                if len(sbts) == 1:
                     tree_data = storage.load(sbts[0])
 
                 tempfile = NamedTemporaryFile()

src/sourmash/sourmash_args.py

@@ -17,7 +17,7 @@
 from . import signature
 from .logging import notify, error, debug_literal
 
-from .index import LinearIndex, MultiIndex
+from .index import (LinearIndex, ZipFileLinearIndex, MultiIndex)
 from . import signature as sig
 from .sbt import SBT
 from .sbtmh import SigLeaf
@@ -143,7 +143,7 @@ def traverse_find_sigs(filenames, yield_all_files=False):
 
 def load_dbs_and_sigs(filenames, query, is_similarity_query, *, cache_size=None):
     """
-    Load one or more SBTs, LCAs, and/or signatures.
+    Load one or more SBTs, LCAs, and/or collections of signatures.
 
     Check for compatibility with query.
 
@@ -251,7 +251,7 @@ def _load_sbt(filename, **kwargs):
 
     try:
         db = load_sbt_index(filename, cache_size=cache_size)
-    except FileNotFoundError as exc:
+    except (FileNotFoundError, TypeError) as exc:
         raise ValueError(exc)
 
     return db
@@ -263,6 +263,16 @@ def _load_revindex(filename, **kwargs):
     return db
 
 
+def _load_zipfile(filename, **kwargs):
+    "Load collection from a .zip file."
+    db = None
+    if filename.endswith('.zip'):
+        traverse_yield_all = kwargs['traverse_yield_all']
+        db = ZipFileLinearIndex.load(filename,
+                                     traverse_yield_all=traverse_yield_all)
+    return db
+
+
 # all loader functions, in order.
 _loader_functions = [
     ("load from stdin", _load_stdin),
@@ -271,6 +281,7 @@ def _load_revindex(filename, **kwargs):
     ("load from file list", _multiindex_load_from_pathlist),
     ("load SBT", _load_sbt),
     ("load revindex", _load_revindex),
+    ("load collection from zipfile", _load_zipfile),
     ]
 
 
@@ -328,8 +339,10 @@ def _load_database(filename, traverse_yield_all, *, cache_size=None):
 def load_file_as_index(filename, yield_all_files=False):
     """Load 'filename' as a database; generic database loader.
 
-    If 'filename' contains an SBT or LCA indexed database, will return
-    the appropriate objects.
+    If 'filename' contains an SBT or LCA indexed database, or a regular
+    Zip file, will return the appropriate objects. If a Zip file and
+    yield_all_files=True, will try to load all files within zip, not just
+    .sig files.
 
     If 'filename' is a JSON file containing one or more signatures, will
     return an Index object containing those signatures.
@@ -346,8 +359,10 @@ def load_file_as_signatures(filename, select_moltype=None, ksize=None,
                             progress=None):
     """Load 'filename' as a collection of signatures. Return an iterable.
 
-    If 'filename' contains an SBT or LCA indexed database, will return
-    a signatures() generator.
+    If 'filename' contains an SBT or LCA indexed database, or a regular
+    Zip file, will return a signatures() generator. If a Zip file and
+    yield_all_files=True, will try to load all files within zip, not just
+    .sig files.
 
     If 'filename' is a JSON file containing one or more signatures, will
     return a list of those signatures.

tests/test_api.py

@@ -49,6 +49,22 @@ def test_load_index_3():
     assert len(sigs) == 2
 
 
+def test_load_index_4():
+    testfile = utils.get_test_data('prot/all.zip')
+    idx = sourmash.load_file_as_index(testfile)
+
+    sigs = list(idx.signatures())
+    assert len(sigs) == 7
+
+
+def test_load_index_4_b():
+    testfile = utils.get_test_data('prot/protein.zip')
+    idx = sourmash.load_file_as_index(testfile)
+
+    sigs = list(idx.signatures())
+    assert len(sigs) == 2
+
+
 def test_load_fasta_as_signature():
     # try loading a fasta file - should fail with informative exception
     testfile = utils.get_test_data('short.fa')

tests/test_cmd_signature.py

@@ -1421,6 +1421,27 @@ def test_sig_describe_1_dir(c):
         assert line.strip() in out
 
 
+@utils.in_tempdir
+def test_sig_describe_1_zipfile(c):
+    # get basic info on multiple signatures in a zipfile
+    sigs = utils.get_test_data('prot/all.zip')
+    c.run_sourmash('sig', 'describe', sigs)
+
+    out = c.last_result.out
+    print(c.last_result)
+
+    expected_output = """\
+k=19 molecule=dayhoff num=0 scaled=100 seed=42 track_abundance=0
+k=19 molecule=dayhoff num=0 scaled=100 seed=42 track_abundance=0
+k=19 molecule=hp num=0 scaled=100 seed=42 track_abundance=0
+k=19 molecule=hp num=0 scaled=100 seed=42 track_abundance=0
+k=19 molecule=protein num=0 scaled=100 seed=42 track_abundance=0
+k=19 molecule=protein num=0 scaled=100 seed=42 track_abundance=0
+""".splitlines()
+    for line in expected_output:
+        assert line.strip() in out
+
+
 @utils.in_thisdir
 def test_sig_describe_stdin(c):
     sig = utils.get_test_data('prot/protein/GCA_001593925.1_ASM159392v1_protein.faa.gz.sig')