reindexer.py

from __future__ import absolute_import

from elasticsearch import helpers

from .annotation import Annotation
from .document import Document
from .elasticsearch_analyzers import ANALYSIS


class Reindexer(object):

    es_models = Annotation, Document
    analysis_settings = ANALYSIS

    def __init__(self, conn, interactive=False):
        self.conn = conn
        self.interactive = interactive

    def _print(self, s):
        if self.interactive:
            print(s)

    def reindex(self, old_index, new_index):
        """Reindex documents using the current mappings."""
        conn = self.conn

        if not conn.indices.exists(old_index):
            raise ValueError("Index {0} does not exist!".format(old_index))

        if conn.indices.exists(new_index):
            self._print("Index {0} already exists. "
                        "The mapping will not be changed.".format(new_index))
        else:
            # Create the new index with (presumably) new mapping config
            conn.indices.create(new_index, body=self.get_index_config())

        # Do the actual reindexing.
        self._print("Reindexing {0} to {1}...".format(old_index, new_index))
        helpers.reindex(conn, old_index, new_index)
        self._print("Reindexing done.")

    def alias(self, index, alias):
        conn = self.conn
        # Remove the alias's current targets.
        is_alias = conn.indices.exists_alias(alias)
        if is_alias:
            real_index = ','.join(conn.indices.get_alias(alias).keys())
            self._print("Deleting alias {alias}... "
                        "(was an alias for {real_index})"
                        .format(alias=alias, real_index=real_index))
            conn.indices.delete_alias(name=alias, index='_all')

        if conn.indices.exists(alias):
            raise RuntimeError("Cannot create alias {alias}, "
                               "name is used by an index."
                               .format(alias=alias))

        # Create new alias
        self._print("Making alias {alias} point to {index}..."
                    .format(alias=alias, index=index))
        conn.indices.put_alias(name=alias, index=index)

    def get_index_config(self):
        # Configure index mappings
        index_config = {'mappings': {},
                        'settings': {'analysis': self.analysis_settings},
                        }
        for model in self.es_models:
            index_config['mappings'].update(model.get_mapping())
        return index_config