docker.container: Recreate container when args change

pyinfra/operations/docker.py

@@ -4,17 +4,20 @@
 as inventory directly.
 """
 
+from typing import Any, Dict
+
 from pyinfra import host
 from pyinfra.api import operation
 from pyinfra.facts.docker import DockerContainer, DockerNetwork, DockerVolume
 
-from .util.docker import handle_docker
+from .util.docker import CONTAINER_CONFIG_HASH_LABEL, ContainerSpec, handle_docker
 
 
 @operation()
 def container(
     container,
     image="",
+    args=None,
     ports=None,
     networks=None,
     volumes=None,
@@ -28,6 +31,7 @@ def container(
     Manage Docker containers
 
     + container: name to identify the container
+    + args: list of command-line args to supply to the image
     + image: container image and tag ex: nginx:alpine
     + networks: network list to attach on container
     + ports: port list to expose
@@ -70,56 +74,69 @@ def container(
         )
     """
 
-    existent_container = host.get_fact(DockerContainer, object_id=container)
+    want_spec = ContainerSpec(
+        image,
+        args or list(),
+        set(ports) if ports else set(),
+        set(networks) if networks else set(),
+        volumes or list(),
+        set(env_vars) if env_vars else set(),
+        pull_always,
+    )
 
-    if force:
-        if existent_container:
-            yield handle_docker(
-                resource="container",
-                command="remove",
-                container=container,
-            )
+    existent_container: Dict[str, Any] = next(
+        iter(host.get_fact(DockerContainer, object_id=container)), {}
+    )
 
-    if present:
-        if not existent_container or force:
-            yield handle_docker(
-                resource="container",
-                command="create",
-                container=container,
-                image=image,
-                ports=ports,
-                networks=networks,
-                volumes=volumes,
-                env_vars=env_vars,
-                pull_always=pull_always,
-                present=present,
-                force=force,
-                start=start,
-            )
-
-    if existent_container and start:
-        if existent_container[0]["State"]["Status"] != "running":
-            yield handle_docker(
-                resource="container",
-                command="start",
-                container=container,
-            )
-
-    if existent_container and not start:
-        if existent_container[0]["State"]["Status"] == "running":
-            yield handle_docker(
-                resource="container",
-                command="stop",
-                container=container,
-            )
-
-    if existent_container and not present:
+    old_hash = (
+        existent_container.get("Config", {})
+        .get("Labels", {})
+        .get(CONTAINER_CONFIG_HASH_LABEL, None)
+    )
+
+    container_spec_changed = old_hash != want_spec.config_hash()
+
+    is_running = existent_container.get("State", {}).get("Status", "") == "running"
+    recreating = existent_container and (force or container_spec_changed)
+    removing = existent_container and not present
+
+    do_remove = recreating or removing
+    do_create = not removing and ((present and not existent_container) or recreating)
+    do_start = present and start and (recreating or not is_running)
+    do_stop = not start and not removing and is_running and not recreating
+
+    if not (do_remove or do_create or do_start or do_stop):
+        host.noop("container configuration is already correct")
+
+    if do_remove:
         yield handle_docker(
             resource="container",
             command="remove",
             container=container,
         )
 
+    if do_create:
+        yield handle_docker(
+            resource="container",
+            command="create",
+            container=container,
+            spec=want_spec,
+        )
+
+    if do_start:
+        yield handle_docker(
+            resource="container",
+            command="start",
+            container=container,
+        )
+
+    if do_stop:
+        yield handle_docker(
+            resource="container",
+            command="stop",
+            container=container,
+        )
+
 
 @operation(is_idempotent=False)
 def image(image, present=True):

pyinfra/operations/util/docker.py

@@ -1,38 +1,83 @@
+import dataclasses
+import hashlib
+import json
+from typing import Any, List, Set
+
 from pyinfra.api import OperationError
 
+CONTAINER_CONFIG_HASH_LABEL = "com.github.pyinfra.config-hash"
 
-def _create_container(**kwargs):
-    command = []
 
-    networks = kwargs["networks"] if kwargs["networks"] else []
-    ports = kwargs["ports"] if kwargs["ports"] else []
-    volumes = kwargs["volumes"] if kwargs["volumes"] else []
-    env_vars = kwargs["env_vars"] if kwargs["env_vars"] else []
+def _json_repr(obj: Any):
+    try:
+        return dataclasses.asdict(obj)
+    except TypeError:
+        pass
+
+    if isinstance(obj, set):
+        return sorted(obj)
+
+    # If there are other alternative types to try (e.g. dates) then do so here
+
+    raise TypeError(f"object {type(obj).__name__} not serializable")
+
 
-    if kwargs["image"] == "":
-        raise OperationError("missing 1 required argument: 'image'")
+@dataclasses.dataclass
+class ContainerSpec:
+    image: str = ""
+    args: List[str] = dataclasses.field(default_factory=list)
+    ports: Set[str] = dataclasses.field(default_factory=set)
+    networks: Set[str] = dataclasses.field(default_factory=set)
+    volumes: List[str] = dataclasses.field(default_factory=list)
+    env_vars: Set[str] = dataclasses.field(default_factory=set)
+    pull_always: bool = False
 
-    command.append("docker container create --name {0}".format(kwargs["container"]))
+    def container_create_args(self):
+        args = [f"--label '{CONTAINER_CONFIG_HASH_LABEL}={self.config_hash()}'"]
+        for network in sorted(self.networks):
+            args.append("--network {0}".format(network))
 
-    for network in networks:
-        command.append("--network {0}".format(network))
+        for port in sorted(self.ports):
+            args.append("-p {0}".format(port))
 
-    for port in ports:
-        command.append("-p {0}".format(port))
+        for volume in self.volumes:
+            args.append("-v {0}".format(volume))
 
-    for volume in volumes:
-        command.append("-v {0}".format(volume))
+        for env_var in sorted(self.env_vars):
+            args.append("-e {0}".format(env_var))
 
-    for env_var in env_vars:
-        command.append("-e {0}".format(env_var))
+        if self.pull_always:
+            args.append("--pull always")
+
+        args.append(self.image)
+        args.extend(self.args)
+
+        return args
+
+    def config_hash(self) -> str:
+        serialized = json.dumps(
+            self,
+            default=_json_repr,
+            ensure_ascii=False,
+            sort_keys=True,
+            indent=None,
+            separators=(",", ":"),
+        ).encode("utf-8")
+        return hashlib.sha256(serialized).hexdigest()
+
+
+def _create_container(**kwargs):
+    if "spec" not in kwargs:
+        raise OperationError("missing 1 required argument: 'spec'")
 
-    if kwargs["pull_always"]:
-        command.append("--pull always")
+    spec = kwargs["spec"]
 
-    command.append(kwargs["image"])
+    if not spec.image:
+        raise OperationError("Docker image not specified")
 
-    if kwargs["start"]:
-        command.append("; {0}".format(_start_container(container=kwargs["container"])))
+    command = [
+        "docker container create --name {0}".format(kwargs["container"])
+    ] + spec.container_create_args()
 
     return " ".join(command)
 

tests/operations/docker.container/add_and_start_no_existent_container.json

@@ -2,18 +2,37 @@
     "kwargs": {
         "container": "nginx",
         "image": "nginx:alpine",
+        "args": [
+            "nginx-debug",
+            "-g",
+            "'daemon off;'"
+        ],
+        "networks": [
+            "foo",
+            "bar"
+        ],
+        "volumes": [
+            "/host/a:/container/a",
+            "/host/b:/container/b"
+        ],
         "ports": [
-            "80:80"
+            "80:80",
+            "8081:8081"
+        ],
+        "env_vars": [
+            "ENV_A=foo",
+            "ENV_B=bar"
         ],
         "present": true,
         "start": true
     },
     "facts": {
         "docker.DockerContainer": {
-            "object_id=nginx": [] 
+            "object_id=nginx": []
         }
     },
     "commands": [
-        "docker container create --name nginx -p 80:80 nginx:alpine ; docker container start nginx"
+        "docker container create --name nginx --label 'com.github.pyinfra.config-hash=72d37ab8f5ea3db48272d045bc10e211bbd628f2b4bab5c54d948b073313c9a3' --network bar --network foo -p 8081:8081 -p 80:80 -v /host/a:/container/a -v /host/b:/container/b -e ENV_A=foo -e ENV_B=bar nginx:alpine nginx-debug -g 'daemon off;'",
+        "docker container start nginx"
     ]
 }