Add support for filtering images and containers

[`filters` is a json encoded value of the filters (a map[string][string]) to process on the images list. ][1]
The tricky thing is that we must convert boolean value to string and any filter value to list to make a `map[string][string]` json format

[1]: https://docs.docker.com/reference/api/docker_remote_api_v1.14/#list-images

2 files changed, 14 insertions, 1 deletions

diff --git a/docker/utils/__init__.py b/docker/utils/__init__.py
index 5d2c1b8..ade4f0b 100644
--- a/docker/utils/__init__.py
+++ b/docker/utils/__init__.py
@@ -1,4 +1,5 @@
 from .utils import (
     compare_version, convert_port_bindings, convert_volume_binds,
-    mkbuildcontext, ping, tar, parse_repository_tag, parse_host
+    mkbuildcontext, ping, tar, parse_repository_tag, parse_host,
+    convert_filters
 ) # flake8: noqa
diff --git a/docker/utils/utils.py b/docker/utils/utils.py
index fb05a1e..514a75b 100644
--- a/docker/utils/utils.py
+++ b/docker/utils/utils.py
@@ -14,6 +14,7 @@
 
 import io
 import os
+import json
 import tarfile
 import tempfile
 from distutils.version import StrictVersion
@@ -233,3 +234,14 @@ def parse_host(addr):
     if proto == "http+unix":
         return "%s://%s" % (proto, host)
     return "%s://%s:%d" % (proto, host, port)
+
+
+def convert_filters(filters):
+    result = {}
+    for k, v in six.iteritems(filters):
+        if isinstance(v, bool):
+            v = 'true' if v else 'false'
+        if not isinstance(v, list):
+            v = [v, ]
+        result[k] = v
+    return json.dumps(result)