Write mz config to deterministic location (#32240)

The file name is based off a hash of the contents. This avoids
accumulating many temporary config files in a local worktree.

### Checklist

- [ ] This PR has adequate test coverage / QA involvement has been duly
considered. ([trigger-ci for additional test/nightly
runs](https://trigger-ci.dev.materialize.com/))
- [ ] This PR has an associated up-to-date [design
doc](https://github.com/MaterializeInc/materialize/blob/main/doc/developer/design/README.md),
is a design doc
([template](https://github.com/MaterializeInc/materialize/blob/main/doc/developer/design/00000000_template.md)),
or is sufficiently small to not require a design.
  <!-- Reference the design in the description. -->
- [ ] If this PR evolves [an existing `$T ⇔ Proto$T`
mapping](https://github.com/MaterializeInc/materialize/blob/main/doc/developer/command-and-response-binary-encoding.md)
(possibly in a backwards-incompatible way), then it is tagged with a
`T-proto` label.
- [ ] If this PR will require changes to cloud orchestration or tests,
there is a companion cloud PR to account for those changes that is
tagged with the release-blocker label
([example](MaterializeInc/cloud#5021)).
<!-- Ask in #team-cloud on Slack if you need help preparing the cloud
PR. -->
- [ ] If this PR includes major [user-facing behavior
changes](https://github.com/MaterializeInc/materialize/blob/main/doc/developer/guide-changes.md#what-changes-require-a-release-note),
I have pinged the relevant PM to schedule a changelog post.

---------

Signed-off-by: Moritz Hoffmann <[email protected]>

Author: antiguru

misc/python/materialize/mzcompose/services/mz.py

@@ -7,16 +7,13 @@
 # the Business Source License, use of this software will be governed
 # by the Apache License, Version 2.0.
 
-import tempfile
+import hashlib
 
 import toml
 
-from materialize.mzcompose import (
-    loader,
-)
-from materialize.mzcompose.service import (
-    Service,
-)
+from materialize import MZ_ROOT
+from materialize.mzcompose import loader
+from materialize.mzcompose.service import Service
 
 
 class Mz(Service):
@@ -28,17 +25,6 @@ def __init__(
         environment: str = "staging",
         app_password: str,
     ) -> None:
-        # We must create the temporary config file in a location
-        # that is accessible on the same path in both the ci-builder
-        # container and the host that runs the docker daemon
-        # $TMP does not guarantee that, but loader.composition_path does.
-        config = tempfile.NamedTemporaryFile(
-            dir=loader.composition_path,
-            prefix="tmp_",
-            suffix=".toml",
-            mode="w",
-            delete=False,
-        )
 
         # Production env does not require to specify an endpoint.
         if environment == "production":
@@ -48,7 +34,7 @@ def __init__(
             cloud_endpoint = f"https://api.{environment}.cloud.materialize.com"
             admin_endpoint = f"https://admin.{environment}.cloud.materialize.com"
 
-        toml.dump(
+        config_str = toml.dumps(
             {
                 "profile": "default",
                 "profiles": {
@@ -60,13 +46,21 @@ def __init__(
                     },
                 },
             },
-            config,
         )
-        config.close()
+
+        # We must create the temporary config file in a location
+        # that is accessible on the same path in both the ci-builder
+        # container and the host that runs the docker daemon
+        # $TMP does not guarantee that, but loader.composition_path does.
+        config_hash = hashlib.sha256(config_str.encode()).hexdigest()
+        config_name = (loader.composition_path or MZ_ROOT) / f"tmp_{config_hash}.toml"
+
+        with open(config_name, "w") as f:
+            f.write(config_str)
         super().__init__(
             name=name,
             config={
                 "mzbuild": "mz",
-                "volumes": [f"{config.name}:/root/.config/materialize/mz.toml"],
+                "volumes": [f"{config_name}:/root/.config/materialize/mz.toml"],
             },
         )