Process environment variables defined in compose files (#736)

Reviewed-on: #736
Co-authored-by: David Boreham <david@bozemanpass.com>
Co-committed-by: David Boreham <david@bozemanpass.com>

stack_orchestrator/deploy/k8s/cluster_info.py

@@ -22,7 +22,7 @@ from stack_orchestrator.opts import opts
 from stack_orchestrator.util import env_var_map_from_file
 from stack_orchestrator.deploy.k8s.helpers import named_volumes_from_pod_files, volume_mounts_for_service, volumes_for_pod_files
 from stack_orchestrator.deploy.k8s.helpers import get_node_pv_mount_path
-from stack_orchestrator.deploy.k8s.helpers import envs_from_environment_variables_map
+from stack_orchestrator.deploy.k8s.helpers import envs_from_environment_variables_map, envs_from_compose_file, merge_envs
 from stack_orchestrator.deploy.deploy_util import parsed_pod_files_map_from_file_names, images_for_deployment
 from stack_orchestrator.deploy.deploy_types import DeployEnvVars
 from stack_orchestrator.deploy.spec import Spec, Resources, ResourceLimits
@@ -263,6 +263,13 @@ class ClusterInfo:
                     if opts.o.debug:
                         print(f"image: {image}")
                         print(f"service port: {port}")
+                merged_envs = merge_envs(
+                    envs_from_compose_file(
+                        service_info["environment"]), self.environment_variables.map
+                        ) if "environment" in service_info else self.environment_variables.map
+                envs = envs_from_environment_variables_map(merged_envs)
+                if opts.o.debug:
+                    print(f"Merged envs: {envs}")
                 # Re-write the image tag for remote deployment
                 image_to_use = remote_tag_for_image(
                     image, self.spec.get_image_registry()) if self.spec.get_image_registry() is not None else image
@@ -271,7 +278,7 @@ class ClusterInfo:
                     name=container_name,
                     image=image_to_use,
                     image_pull_policy=image_pull_policy,
-                    env=envs_from_environment_variables_map(self.environment_variables.map),
+                    env=envs,
                     ports=[client.V1ContainerPort(container_port=port)],
                     volume_mounts=volume_mounts,
                     resources=to_k8s_resource_requirements(resources),

stack_orchestrator/deploy/k8s/helpers.py

@@ -17,6 +17,7 @@ from kubernetes import client
 import os
 from pathlib import Path
 import subprocess
+import re
 from typing import Set, Mapping, List
 
 from stack_orchestrator.opts import opts
@@ -214,6 +215,33 @@ def _generate_kind_port_mappings(parsed_pod_files):
     )
 
 
+# Note: this makes any duplicate definition in b overwrite a
+def merge_envs(a: Mapping[str, str], b: Mapping[str, str]) -> Mapping[str, str]:
+    result = {**a, **b}
+    return result
+
+
+def _expand_shell_vars(raw_val: str) -> str:
+    # could be: <string> or ${<env-var-name>} or ${<env-var-name>:-<default-value>}
+    # TODO: implement support for variable substitution and default values
+    # if raw_val is like ${<something>} print a warning and substitute an empty string
+    # otherwise return raw_val
+    match = re.search(r"^\$\{(.*)\}$", raw_val)
+    if match:
+        print(f"WARNING: found unimplemented environment variable substitution: {raw_val}")
+    else:
+        return raw_val
+
+
+# TODO: handle the case where the same env var is defined in multiple places
+def envs_from_compose_file(compose_file_envs: Mapping[str, str]) -> Mapping[str, str]:
+    result = {}
+    for env_var, env_val in compose_file_envs.items():
+        expanded_env_val = _expand_shell_vars(env_val)
+        result.update({env_var: expanded_env_val})
+    return result
+
+
 def envs_from_environment_variables_map(map: Mapping[str, str]) -> List[client.V1EnvVar]:
     result = []
     for env_var, env_val in map.items():