adobe · amuraru · Oct 11, 2025 · Jun 7, 2022 · Jun 7, 2022 · Jun 7, 2022
diff --git a/README.md b/README.md
@@ -43,6 +43,10 @@ Idea came from puppet's hiera.
 
 ```sh
 pip install himl
+# or, optionally install with all extras dependencies: vault and s3 interpolation support
+pip install himl[all]
+# or, specify which extras dependencies you need
+pip install himl[vault,s3]
 ```
 
 ### Using `docker` image

diff --git a/himl/config_generator.py b/himl/config_generator.py
@@ -295,8 +295,9 @@ def exclude_keys(self, keys):
                     logger.info("Excluded key %s not found or already removed", key)
 
     def add_dynamic_data(self):
-        remote_state_retriever = S3TerraformRemoteStateRetriever()
         if "remote_states" in self.generated_data:
+            from .remote_state import S3TerraformRemoteStateRetriever
+            remote_state_retriever = S3TerraformRemoteStateRetriever()
             state_files = self.generated_data["remote_states"]
             remote_states = remote_state_retriever.get_dynamic_data(state_files)
             self.merge_value(self.generated_data, remote_states, self.type_strategies, self.fallback_strategies,

diff --git a/himl/remote_state.py b/himl/remote_state.py
@@ -10,8 +10,10 @@
 
 import json
 
-import boto3
-
+try:
+    import boto3
+except ImportError as e:
+    raise Exception('Error while trying to read remote state, package "boto3" is required and cannot be imported: %s' % e)
 
 class S3TerraformRemoteStateRetriever:
     @staticmethod

diff --git a/himl/secret_resolvers.py b/himl/secret_resolvers.py
@@ -10,9 +10,6 @@
 
 import logging
 import os
-from .simplessm import SimpleSSM
-from .simples3 import SimpleS3
-from .simplevault import SimpleVault
 
 
 class SecretResolver:
@@ -33,7 +30,7 @@ def __init__(self, default_aws_profile=None):
         self.default_aws_profile = default_aws_profile
 
     def supports(self, secret_type):
-        return secret_type == "ssm"
+        return "boto3" in sys.modules && secret_type == "ssm"
 
     def resolve(self, secret_type, secret_params):
         aws_profile = secret_params.get("aws_profile", self.default_aws_profile)
@@ -43,6 +40,7 @@ def resolve(self, secret_type, secret_params):
 
         path = self.get_param_or_exception("path", secret_params)
         region_name = secret_params.get("region_name", "us-east-1")
+        from .simplessm import SimpleSSM
         ssm = SimpleSSM(aws_profile, region_name)
         return ssm.get(path)
 
@@ -52,7 +50,7 @@ def __init__(self, default_aws_profile=None):
         self.default_aws_profile = default_aws_profile
 
     def supports(self, secret_type):
-        return secret_type == "s3"
+        return "boto3" in sys.modules && secret_type == "s3"
 
     def resolve(self, secret_type, secret_params):
         aws_profile = secret_params.get("aws_profile", self.default_aws_profile)
@@ -65,15 +63,17 @@ def resolve(self, secret_type, secret_params):
         region_name = secret_params.get("region_name", "us-east-1")
         base64Encode = secret_params.get("base64encode", False)
         base64Encode = base64Encode == 'true'
+        from .simples3 import SimpleS3
         s3 = SimpleS3(aws_profile, region_name)
         return s3.get(bucket, path, base64Encode)
 
 
 class VaultSecretResolver(SecretResolver):
     def supports(self, secret_type):
-        return secret_type == "vault"
+        return "hvac" in sys.modules && secret_type == "vault"
 
     def resolve(self, secret_type, secret_params):
+        from .simplevault import SimpleVault
         vault = SimpleVault
 
         # Generate a token for a policy
@@ -106,4 +106,4 @@ def resolve(self, secret_type, secret_params):
             if resolver.supports(secret_type):
                 return resolver.resolve(secret_type, secret_params)
 
-        raise Exception("Could not resolve secret type '{}' with params {}".format(secret_type, secret_params))
+        raise Exception("Could not resolve secret type '{}' with params {}. Check if you installed the required 3rd party modules.".format(secret_type, secret_params))
diff --git a/setup.py b/setup.py
@@ -15,10 +15,18 @@
     'backports.functools_lru_cache==1.6.6',
     'pathlib2==2.3.7.post1',
     'pyyaml==6.0.1',
-    'boto3==1.34.6',
-    'hvac==1.2.1'
 ]
 
+_extras_require = {
+    's3': [
+        'boto3==1.34.6',
+    ],
+    'vault': [
+        'hvac==1.2.1',
+    ],
+}
+_extras_require['all'] = [dep for deps in _extras_require.values() for dep in deps]
+
 setup(
     name='himl',
     version="0.15.1",
@@ -54,6 +62,7 @@
     packages=['himl'],
     include_package_data=True,
     install_requires=_install_requires,
+    extras_require=_extras_require,
     entry_points={
         'console_scripts': [
             'himl = himl.main:run',