simple-config: new crate to read/write proxmox simple text config files

Copied from proxmox-backup/src/tools/config.rs

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

Cargo.toml

@@ -30,6 +30,7 @@ members = [
     "proxmox-section-config",
     "proxmox-serde",
     "proxmox-shared-memory",
+    "proxmox-simple-config",
     "proxmox-sortable-macro",
     "proxmox-subscription",
     "proxmox-sys",

proxmox-simple-config/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "proxmox-simple-config"
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+exclude.workspace = true
+description = "Simple key/value format for configuration files."
+
+[dependencies]
+anyhow.workspace = true
+serde_json.workspace = true
+serde = { workspace = true, features = ["derive"] }
+log = { workspace = true, optional = true }
+
+proxmox-schema = { workspace = true, features = ["api-macro", "api-types"] }

proxmox-simple-config/debian/changelog

@@ -0,0 +1,6 @@
+rust-proxmox-simple-config (0.1.0-1) bookworm; urgency=medium
+
+  * initial packaging (copied code from proxmox-backup)
+
+ -- Proxmox Support Team <support@proxmox.com>  Wed, 05 Jun 2024 12:52:06 +0200
+

proxmox-simple-config/debian/control

@@ -0,0 +1,61 @@
+Source: rust-proxmox-simple-config
+Section: rust
+Priority: optional
+Build-Depends: debhelper (>= 12),
+ dh-cargo (>= 25),
+ cargo:native <!nocheck>,
+ rustc:native <!nocheck>,
+ libstd-rust-dev <!nocheck>,
+ librust-anyhow-1+default-dev <!nocheck>,
+ librust-proxmox-schema-3+api-macro-dev (>= 3.1.1-~~) <!nocheck>,
+ librust-proxmox-schema-3+api-types-dev (>= 3.1.1-~~) <!nocheck>,
+ librust-proxmox-schema-3+default-dev (>= 3.1.1-~~) <!nocheck>,
+ librust-serde-1+default-dev <!nocheck>,
+ librust-serde-1+derive-dev <!nocheck>,
+ librust-serde-json-1+default-dev <!nocheck>
+Maintainer: Proxmox Support Team <support@proxmox.com>
+Standards-Version: 4.6.2
+Vcs-Git: git://git.proxmox.com/git/proxmox.git
+Vcs-Browser: https://git.proxmox.com/?p=proxmox.git
+X-Cargo-Crate: proxmox-simple-config
+Rules-Requires-Root: no
+
+Package: librust-proxmox-simple-config-dev
+Architecture: any
+Multi-Arch: same
+Depends:
+ ${misc:Depends},
+ librust-anyhow-1+default-dev,
+ librust-proxmox-schema-3+api-macro-dev (>= 3.1.1-~~),
+ librust-proxmox-schema-3+api-types-dev (>= 3.1.1-~~),
+ librust-proxmox-schema-3+default-dev (>= 3.1.1-~~),
+ librust-serde-1+default-dev,
+ librust-serde-1+derive-dev,
+ librust-serde-json-1+default-dev
+Suggests:
+ librust-proxmox-simple-config+log-dev (= ${binary:Version})
+Provides:
+ librust-proxmox-simple-config+default-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0+default-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1+default-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1.0-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1.0+default-dev (= ${binary:Version})
+Description: Simple key/value format for configuration files - Rust source code
+ Source code for Debianized Rust crate "proxmox-simple-config"
+
+Package: librust-proxmox-simple-config+log-dev
+Architecture: any
+Multi-Arch: same
+Depends:
+ ${misc:Depends},
+ librust-proxmox-simple-config-dev (= ${binary:Version}),
+ librust-log-0.4+default-dev (>= 0.4.17-~~)
+Provides:
+ librust-proxmox-simple-config-0+log-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1+log-dev (= ${binary:Version}),
+ librust-proxmox-simple-config-0.1.0+log-dev (= ${binary:Version})
+Description: Simple key/value format for configuration files - feature "log"
+ This metapackage enables feature "log" for the Rust proxmox-simple-config
+ crate, by pulling in any additional dependencies needed by that feature.

proxmox-simple-config/debian/copyright

@@ -0,0 +1,18 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+
+Files:
+ *
+Copyright: 2019 - 2024 Proxmox Server Solutions GmbH <support@proxmox.com>
+License: AGPL-3.0-or-later
+ This program is free software: you can redistribute it and/or modify it under
+ the terms of the GNU Affero General Public License as published by the Free
+ Software Foundation, either version 3 of the License, or (at your option) any
+ later version.
+ .
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ details.
+ .
+ You should have received a copy of the GNU Affero General Public License along
+ with this program. If not, see <https://www.gnu.org/licenses/>.

proxmox-simple-config/debian/debcargo.toml

@@ -0,0 +1,7 @@
+overlay = "."
+crate_src_path = ".."
+maintainer = "Proxmox Support Team <support@proxmox.com>"
+
+[source]
+vcs_git = "git://git.proxmox.com/git/proxmox.git"
+vcs_browser = "https://git.proxmox.com/?p=proxmox.git"

proxmox-simple-config/src/lib.rs

@@ -0,0 +1,173 @@
+//! Our 'key: value' config format.
+
+use std::io::Write;
+
+use anyhow::{bail, format_err, Error};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+use proxmox_schema::{ObjectSchemaType, Schema};
+
+type Object = serde_json::Map<String, Value>;
+
+fn object_schema(schema: &'static Schema) -> Result<&'static dyn ObjectSchemaType, Error> {
+    Ok(match schema {
+        Schema::Object(schema) => schema,
+        Schema::AllOf(schema) => schema,
+        _ => bail!("invalid schema for config, must be an object schema"),
+    })
+}
+
+/// Parse a full string representing a config file.
+pub fn from_str<T: for<'de> Deserialize<'de>>(
+    input: &str,
+    schema: &'static Schema,
+) -> Result<T, Error> {
+    Ok(serde_json::from_value(value_from_str(input, schema)?)?)
+}
+
+/// Parse a full string representing a config file.
+pub fn value_from_str(input: &str, schema: &'static Schema) -> Result<Value, Error> {
+    let schema = object_schema(schema)?;
+
+    let mut config = Object::new();
+    let mut lines = input.lines().enumerate().peekable();
+    let mut description = String::new();
+
+    while let Some((_, line)) = lines.next_if(|(_, line)| line.starts_with('#')) {
+        description.push_str(&line[1..]);
+        description.push('\n');
+    }
+
+    if !description.is_empty() {
+        config.insert("description".to_string(), Value::String(description));
+    }
+
+    for (lineno, line) in lines {
+        let line = line.trim();
+        if line.starts_with('#') || line.is_empty() {
+            continue;
+        }
+
+        parse_line(&mut config, line, schema)
+            .map_err(|err| format_err!("line {}: {}", lineno, err))?;
+    }
+
+    Ok(Value::Object(config))
+}
+
+/// Parse a single `key: value` line from a config file.
+fn parse_line(
+    config: &mut Object,
+    line: &str,
+    schema: &'static dyn ObjectSchemaType,
+) -> Result<(), Error> {
+    if line.starts_with('#') || line.is_empty() {
+        return Ok(());
+    }
+
+    let colon = line
+        .find(':')
+        .ok_or_else(|| format_err!("missing colon to separate key from value"))?;
+    if colon == 0 {
+        bail!("empty key not allowed");
+    }
+
+    let key = &line[..colon];
+    let value = line[(colon + 1)..].trim_start();
+
+    parse_key_value(config, key, value, schema)
+}
+
+/// Lookup the key in the schema, parse the value and insert it into the config object.
+fn parse_key_value(
+    config: &mut Object,
+    key: &str,
+    value: &str,
+    schema: &'static dyn ObjectSchemaType,
+) -> Result<(), Error> {
+    let schema = match schema.lookup(key) {
+        Some((_optional, schema)) => Some(schema),
+        None if schema.additional_properties() => None,
+        None => bail!(
+            "invalid key '{}' and schema does not allow additional properties",
+            key
+        ),
+    };
+
+    let value = parse_value(value, schema)?;
+    config.insert(key.to_owned(), value);
+    Ok(())
+}
+
+/// For this we can just reuse the schema's "parse_simple_value".
+///
+/// "Additional" properties (`None` schema) will simply become strings.
+///
+/// Note that this does not handle Object or Array types at all, so if we want to support them
+/// natively without going over a `String` type, we can add this here.
+fn parse_value(value: &str, schema: Option<&'static Schema>) -> Result<Value, Error> {
+    match schema {
+        None => Ok(Value::String(value.to_owned())),
+        Some(schema) => schema.parse_simple_value(value),
+    }
+}
+
+/// Parse a string as a property string into a deserializable type. This is just a short wrapper
+/// around deserializing the s
+pub fn from_property_string<T>(input: &str, schema: &'static Schema) -> Result<T, Error>
+where
+    T: for<'de> Deserialize<'de>,
+{
+    Ok(serde_json::from_value(
+        schema.parse_property_string(input)?,
+    )?)
+}
+
+/// Serialize a data structure using a 'key: value' config file format.
+pub fn to_bytes<T: Serialize>(value: &T, schema: &'static Schema) -> Result<Vec<u8>, Error> {
+    value_to_bytes(&serde_json::to_value(value)?, schema)
+}
+
+/// Serialize a json value using a 'key: value' config file format.
+pub fn value_to_bytes(value: &Value, schema: &'static Schema) -> Result<Vec<u8>, Error> {
+    let schema = object_schema(schema)?;
+
+    schema.verify_json(value)?;
+
+    let object = value
+        .as_object()
+        .ok_or_else(|| format_err!("value must be an object"))?;
+
+    let mut out = Vec::new();
+    object_to_writer(&mut out, object)?;
+    Ok(out)
+}
+
+/// Note: the object must have already been verified at this point.
+fn object_to_writer(output: &mut dyn Write, object: &Object) -> Result<(), Error> {
+    // special key `description` for multi-line notes, must be written before everything else
+    if let Some(Value::String(description)) = object.get("description") {
+        for lines in description.lines() {
+            writeln!(output, "#{}", lines)?;
+        }
+    }
+
+    for (key, value) in object.iter() {
+        match value {
+            _ if key == "description" => continue, // skip description as we handle it above
+            Value::Null => continue,               // delete this entry
+            Value::Bool(v) => writeln!(output, "{}: {}", key, v)?,
+            Value::String(v) => {
+                if v.as_bytes().contains(&b'\n') {
+                    bail!("value for {} contains newlines", key);
+                }
+                writeln!(output, "{}: {}", key, v)?
+            }
+            Value::Number(v) => writeln!(output, "{}: {}", key, v)?,
+            Value::Array(_) => bail!("arrays are not supported in config files"),
+            Value::Object(_) => bail!("complex objects are not supported in config files"),
+        }
+    }
+    Ok(())
+}