Move idea to programming/configuration_files_proposal and flesh out

2 files changed, 91 insertions, 9 deletions

diff --git a/IDEAS.org b/IDEAS.org
index 633079a7..8427cc4e 100644
--- a/IDEAS.org
+++ b/IDEAS.org
@@ -171,15 +171,7 @@ Vivaldi's "spatial navigation" supposedly does this, but chokes on D+.
 - https://github.com/DavHau/nix-portable/issues/66
 - https://github.com/nix-community/home-manager/issues/3752#issuecomment-1566179742
 
-* Standard configuration processing layer
-
-- Standardize a way to write programs that generate configuration files, so programs can be configured using these programs instead of plain configuration files.
-- For example, GitHub Actions could be written in a declarative way using libraries with pre-defined patterns.
-- Languages such as Starlark, Dhall, Jsonnet are already designed for this purpose.
-- Should have great sandboxing, ensured finite fast runtimes, but also modularization (e.g. using libs)
-- Maybe use WASM in some fashion?
-- Maybe text files with some kind of shebang that describes if the file is Starlark, Dhall or what.
-
+* [[programming/configuration_files_proposal.md][Standard configuration processing layer]]
 * Databases in text markup documents
 
 - Embed queries of tables
diff --git a/programming/configuration_files_proposal.md b/programming/configuration_files_proposal.md
new file mode 100644
index 00000000..e42c4e50
--- /dev/null
+++ b/programming/configuration_files_proposal.md
@@ -0,0 +1,90 @@
+# Configuration files proposal
+
+No one will ever agree on the ideal configuration file format.
+Therefore, we should allow people to use their preferred configuration file format in all programs.
+
+## Rough idea
+
+Write libraries for as many languages as possible that read files like:
+
+```
+#? yaml
+my configuration:
+  option: value
+```
+
+```
+#? json
+{"my configuration": {"option": "value"}}
+```
+
+and produces a JSON string with the "parsed" input from the second line onwards.
+(Or optionally, a data structure appropriate for the language that you are using.)
+
+If your program uses this library to read configuration, then your users can write their configuration in their preferred language.
+
+## Challenges
+
+* How to prevent arbitrary code execution and other attacks?
+* How to support as many configuration languages as possible?
+
+## Possible solutions
+
+Use capability-based runtimes and embed capabilities in the first line of the configuration file:
+
+```
+                                                  # Allow the specific format parser to...
++file(./**)                                       # ... read files in the same directory as the configuration file and descendants.
++hostname                                         # ... access the hostname.
++load(https://example.com/file,sha256:...,/file)  # ... download a file from the Internet and expose it to the parser.
+...
+```
+
+Be able to refer to different parsers:
+
+```
+# Built-in parsers
+json
+yaml
+...
+
+# Parsers installed on the local system
+/path/to/my/parser
+
+# Download parsers on demand
+https://example.com/foo-parser
+```
+
+## Possible implementation
+
+Use WASM runtimes:
+
+* They already support capabilities.
+* Parsers can be distributed as WASM blobs.
+
+## Motivating examples
+
+### Declarative CI
+
+`.github/workflows/workflow.yaml`:
+
+```
+#? https://jsonnet.org/jsonnet.wasm +load(https://jsonnetci.com/rust.libsonnet,sha256:...,/rust.libsonnet)
+local rust = import '/rust.libsonnet';
+
+rust.github({
+  'supported-archs': ['x86_64-unknown-linux-gnu', ...],
+  'attach-binaries-to-releases': true,
+  'upload-to-docsrs': true,
+  ...
+})
+```
+
+but also `.gitlab-ci.yml`:
+
+```
+#? https://jsonnet.org/jsonnet.wasm +load(https://jsonnetci.com/rust.libsonnet,sha256:...,/rust.libsonnet)
+local rust = import '/rust.libsonnet';
+
+rust.gitlab(...)
+```