refactor: Add config file writers to v2

Cargo.toml

@@ -38,6 +38,7 @@ insta = { version = "1.40", features = ["glob"] }
 hyper = { version = "1.4.1", features = ["full"] }
 hyper-util = "0.1.8"
 itertools = "0.14.0"
+java-properties = "2.0"
 json-patch = "4.0.0"
 k8s-openapi = { version = "0.27.0", default-features = false, features = ["schemars", "v1_35"] }
 # We use rustls instead of openssl for easier portability, e.g. so that we can build stackablectl without the need to vendor (build from source) openssl
@@ -89,6 +90,7 @@ url = { version = "2.5.2", features = ["serde"] }
 uuid = "1.23"
 winnow = "1.0.3"
 x509-cert = { version = "0.2.5", features = ["builder"] }
+xml = "1.3"
 zeroize = "1.8.1"
 
 [workspace.lints.clippy]

crates/stackable-operator/Cargo.toml

@@ -36,6 +36,7 @@ educe.workspace = true
 futures.workspace = true
 http.workspace = true
 indexmap.workspace = true
+java-properties.workspace = true
 jiff.workspace = true
 json-patch = { workspace = true, features = ["schemars"] }
 k8s-openapi.workspace = true
@@ -57,6 +58,7 @@ tracing-subscriber.workspace = true
 url.workspace = true
 uuid.workspace = true
 winnow = { workspace = true, optional = true }
+xml.workspace = true
 
 [dev-dependencies]
 indoc.workspace = true

crates/stackable-operator/src/crd/scaler/mod.rs

@@ -31,8 +31,8 @@ pub mod versioned {
         ///
         /// Upstream issues:
         ///
-        /// - https://github.com/kubernetes/kubernetes/issues/105533
-        /// - https://github.com/Arnavion/k8s-openapi/issues/136
+        /// - <https://github.com/kubernetes/kubernetes/issues/105533>
+        /// - <https://github.com/Arnavion/k8s-openapi/issues/136>
         pub replicas: u16,
     }
 }

crates/stackable-operator/src/v2/builder/meta.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 
 /// Infallible variant of
-/// [`stackable_operator::builder::meta::ObjectMetaBuilder::ownerreference_from_resource`]
+/// [`crate::builder::meta::ObjectMetaBuilder::ownerreference_from_resource`]
 pub fn ownerreference_from_resource(
     resource: &(impl Resource<DynamicType = ()> + HasName + HasUid),
     block_owner_deletion: Option<bool>,

crates/stackable-operator/src/v2/builder/pdb.rs

@@ -9,7 +9,7 @@ use crate::{
 };
 
 /// Infallible variant of
-/// [`stackable_operator::builder::pdb::PodDisruptionBudgetBuilder::new_with_role`]
+/// [`crate::builder::pdb::PodDisruptionBudgetBuilder::new_with_role`]
 pub fn pod_disruption_budget_builder_with_role(
     owner: &(impl Resource<DynamicType = ()> + HasName + NameIsValidLabelValue + HasUid),
     product_name: &ProductName,

crates/stackable-operator/src/v2/builder/pod/container.rs

@@ -23,7 +23,7 @@ pub enum Error {
     ParseEnvVarName { env_var_name: String },
 }
 
-/// Infallible variant of [`stackable_operator::builder::pod::container::ContainerBuilder::new`]
+/// Infallible variant of [`crate::builder::pod::container::ContainerBuilder::new`]
 pub fn new_container_builder(container_name: &ContainerName) -> ContainerBuilder {
     ContainerBuilder::new(container_name.as_ref()).expect("should be a valid container name")
 }

crates/stackable-operator/src/v2/builder/pod/volume.rs

@@ -5,7 +5,7 @@ use crate::{
     v2::types::kubernetes::{ListenerClassName, ListenerName, PersistentVolumeClaimName},
 };
 
-/// Infallible variant of [`stackable_operator::builder::pod::volume::ListenerReference`]
+/// Infallible variant of [`crate::builder::pod::volume::ListenerReference`]
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum ListenerReference {
     ListenerClass(ListenerClassName),
@@ -26,7 +26,7 @@ impl From<&ListenerReference> for crate::builder::pod::volume::ListenerReference
 }
 
 /// Infallible variant of
-/// [`stackable_operator::builder::pod::volume::ListenerOperatorVolumeSourceBuilder::build_pvc`]
+/// [`crate::builder::pod::volume::ListenerOperatorVolumeSourceBuilder::build_pvc`]
 pub fn listener_operator_volume_source_builder_build_pvc(
     listener_reference: &ListenerReference,
     labels: &Labels,

crates/stackable-operator/src/v2/cluster_resources.rs

@@ -9,7 +9,7 @@ use crate::{
     v2::{NameIsValidLabelValue, macros::attributed_string_type::MAX_LABEL_VALUE_LENGTH},
 };
 
-/// Infallible variant of [`stackable_operator::cluster_resources::ClusterResources::new`]
+/// Infallible variant of [`crate::cluster_resources::ClusterResources::new`]
 #[allow(clippy::too_many_arguments)]
 pub fn cluster_resources_new<'a>(
     product_name: &ProductName,

crates/stackable-operator/src/v2/config_file_writer.rs

@@ -0,0 +1,144 @@
+//! Writers for Hadoop XML config files and Java `.properties` files.
+
+use std::{fmt::Write as _, io::Write};
+
+use java_properties::{PropertiesError, PropertiesWriter};
+use snafu::{ResultExt, Snafu};
+use xml::escape::escape_str_attribute;
+
+#[derive(Debug, Snafu)]
+pub enum PropertiesWriterError {
+    #[snafu(display("failed to create properties file"))]
+    Properties { source: PropertiesError },
+
+    #[snafu(display("failed to convert properties file byte array to UTF-8"))]
+    FromUtf8 { source: std::string::FromUtf8Error },
+}
+
+/// Creates a common Java properties file string in the format:
+/// `property_1=value_1\nproperty_2=value_2\n`.
+pub fn to_java_properties_string<'a, T>(properties: T) -> Result<String, PropertiesWriterError>
+where
+    T: Iterator<Item = (&'a String, &'a Option<String>)>,
+{
+    let mut output = Vec::new();
+    write_java_properties(&mut output, properties)?;
+    String::from_utf8(output).context(FromUtf8Snafu)
+}
+
+/// Writes Java properties to the given writer. A `None` value is written as an
+/// empty value (`key=`).
+fn write_java_properties<'a, W, T>(writer: W, properties: T) -> Result<(), PropertiesWriterError>
+where
+    W: Write,
+    T: Iterator<Item = (&'a String, &'a Option<String>)>,
+{
+    let mut writer = PropertiesWriter::new(writer);
+    for (k, v) in properties {
+        let property_value = v.as_deref().unwrap_or_default();
+        writer.write(k, property_value).context(PropertiesSnafu)?;
+    }
+    writer.flush().context(PropertiesSnafu)?;
+    Ok(())
+}
+
+/// Converts properties into a Hadoop configuration XML, including the wrapping
+/// `<configuration>...</configuration>` elements. Properties with a `None` value
+/// are skipped. Keys and values are XML-escaped.
+pub fn to_hadoop_xml<'a, T>(properties: T) -> String
+where
+    T: Iterator<Item = (&'a String, &'a Option<String>)>,
+{
+    let mut snippet = String::new();
+    for (k, v) in properties {
+        let escaped_value = match v {
+            Some(value) => escape_str_attribute(value),
+            None => continue,
+        };
+        let escaped_key = escape_str_attribute(k);
+        write!(
+            snippet,
+            "  <property>\n    <name>{escaped_key}</name>\n    <value>{escaped_value}</value>\n  </property>\n"
+        )
+        .expect("writing to a String is infallible");
+    }
+    format!("<?xml version=\"1.0\"?>\n<configuration>\n{snippet}</configuration>")
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::BTreeMap;
+
+    use super::*;
+
+    fn xml(pairs: &[(&str, Option<&str>)]) -> String {
+        let map: BTreeMap<String, Option<String>> = pairs
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.map(str::to_string)))
+            .collect();
+        to_hadoop_xml(map.iter())
+    }
+
+    fn props(pairs: &[(&str, Option<&str>)]) -> String {
+        let map: BTreeMap<String, Option<String>> = pairs
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.map(str::to_string)))
+            .collect();
+        to_java_properties_string(map.iter()).unwrap()
+    }
+
+    #[test]
+    fn hadoop_xml_wraps_empty_configuration() {
+        assert_eq!(
+            xml(&[]),
+            "<?xml version=\"1.0\"?>\n<configuration>\n</configuration>"
+        );
+    }
+
+    #[test]
+    fn hadoop_xml_renders_single_property() {
+        assert_eq!(
+            xml(&[("fs.defaultFS", Some("hdfs://hdfs/"))]),
+            "<?xml version=\"1.0\"?>\n<configuration>\n  \
+             <property>\n    <name>fs.defaultFS</name>\n    \
+             <value>hdfs://hdfs/</value>\n  </property>\n</configuration>"
+        );
+    }
+
+    #[test]
+    fn hadoop_xml_skips_none_values() {
+        assert_eq!(
+            xml(&[("kept", Some("1")), ("dropped", None)]),
+            "<?xml version=\"1.0\"?>\n<configuration>\n  \
+             <property>\n    <name>kept</name>\n    \
+             <value>1</value>\n  </property>\n</configuration>"
+        );
+    }
+
+    #[test]
+    fn hadoop_xml_escapes_special_characters() {
+        let rendered = xml(&[("k", Some("<a>&b"))]);
+        assert!(
+            rendered.contains("<value>&lt;a&gt;&amp;b</value>"),
+            "{rendered}"
+        );
+    }
+
+    #[test]
+    fn java_properties_renders_key_value() {
+        assert_eq!(props(&[("a", Some("1")), ("b", Some("2"))]), "a=1\nb=2\n");
+    }
+
+    #[test]
+    fn java_properties_renders_none_as_empty() {
+        assert_eq!(props(&[("none", None)]), "none=\n");
+    }
+
+    #[test]
+    fn java_properties_escapes_colon_in_value() {
+        assert_eq!(
+            props(&[("url", Some("file://this/location/file.abc"))]),
+            "url=file\\://this/location/file.abc\n"
+        );
+    }
+}

crates/stackable-operator/src/v2/config_overrides.rs

@@ -9,7 +9,7 @@ use crate::{
     config::merge::Merge, k8s_openapi::DeepMerge, schemars, utils::crds::raw_object_schema,
 };
 
-// Variant of [`stackable_operator::config_overrides::KeyValueConfigOverrides`] that implements
+// Variant of [`crate::config_overrides::KeyValueConfigOverrides`] that implements
 // Merge
 /// Flat key-value overrides for `*.properties`, Hadoop XML, etc.
 ///
@@ -22,7 +22,7 @@ pub struct KeyValueConfigOverrides {
     pub overrides: BTreeMap<String, Option<String>>,
 }
 
-// Variant of [`stackable_operator::config_overrides::JsonConfigOverrides`] with the following
+// Variant of [`crate::config_overrides::JsonConfigOverrides`] with the following
 // changes:
 // - Implements Default
 // - Implements Merge by using a Sequence variant which is not exposed in the CRD
@@ -63,7 +63,7 @@ pub enum JsonConfigOverrides {
 }
 
 impl JsonConfigOverrides {
-    // Infallible variant of [`stackable_operator::config_overrides::JsonConfigOverrides::apply`]
+    // Infallible variant of [`crate::config_overrides::JsonConfigOverrides::apply`]
     pub fn apply(&self, base: &serde_json::Value) -> serde_json::Value {
         match self {
             Self::JsonMergePatch(patch) => {