1 files changed, 75 insertions, 0 deletions
diff --git a/bsie/lib/builder.py b/bsie/lib/builder.py
new file mode 100644
index 0000000..3a15311
--- /dev/null
+++ b/bsie/lib/builder.py
@@ -0,0 +1,75 @@
+
+# standard imports
+import logging
+import typing
+
+# bsie imports
+from bsie.extractor import ExtractorBuilder
+from bsie.reader import ReaderBuilder
+from bsie.utils import errors
+
+# inner-module imports
+from . import pipeline
+
+# exports
+__all__: typing.Sequence[str] = (
+    'PipelineBuilder',
+    )
+
+
+## code ##
+
+logger = logging.getLogger(__name__)
+
+class PipelineBuilder():
+    """Build `bsie.tools.pipeline.Pipeline` instances."""
+
+    # builder for Readers.
+    rbuild: ReaderBuilder
+
+    # builder for Extractors.
+    ebuild: ExtractorBuilder
+
+    def __init__(
+            self,
+            reader_builder: ReaderBuilder,
+            extractor_builder: ExtractorBuilder,
+            ):
+        self.rbuild = reader_builder
+        self.ebuild = extractor_builder
+
+    def build(self) -> pipeline.Pipeline:
+        """Return a Pipeline instance."""
+        ext2rdr = {}
+
+        for eidx in self.ebuild:
+            # build extractor
+            try:
+                ext = self.ebuild.build(eidx)
+
+            except errors.LoaderError as err: # failed to load extractor; skip
+                logger.error('failed to load extractor: %s', err)
+                continue
+
+            except errors.BuilderError as err: # failed to build instance; skip
+                logger.error(str(err))
+                continue
+
+            try:
+                # get reader required by extractor
+                if ext.CONTENT_READER is not None:
+                    rdr = self.rbuild.build(ext.CONTENT_READER)
+                else:
+                    rdr = None
+                # store extractor
+                ext2rdr[ext] = rdr
+
+            except errors.LoaderError as err: # failed to load reader
+                logger.error('failed to load reader: %s', err)
+
+            except errors.BuilderError as err: # failed to build reader
+                logger.error(str(err))
+
+        return pipeline.Pipeline(ext2rdr)
+
+## EOF ##