[pbs-devel] [PATCH proxmox-backup 3/5] fix #3067: api: add multi-line comments to node.cfg

[Stefan Sterz <s.sterz@proxmox.com>]

add support for multiline comments to node.cfg, similar to how pve
handles multi-line comments

Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>
---
 pbs-api-types/src/lib.rs |  9 ++++++
 src/config/node.rs       |  4 +--
 src/tools/config.rs      | 62 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/pbs-api-types/src/lib.rs b/pbs-api-types/src/lib.rs
index 754e7b22..3892980d 100644
--- a/pbs-api-types/src/lib.rs
+++ b/pbs-api-types/src/lib.rs
@@ -137,6 +137,8 @@ const_regex! {
 
     pub SINGLE_LINE_COMMENT_REGEX = r"^[[:^cntrl:]]*$";
 
+    pub MULTI_LINE_COMMENT_REGEX = r"(?m)^([[:^cntrl:]]*)\s*$";
+
     pub BACKUP_REPO_URL_REGEX = concat!(
         r"^^(?:(?:(",
         USER_ID_REGEX_STR!(), "|", APITOKEN_ID_REGEX_STR!(),
@@ -273,6 +275,13 @@ pub const SINGLE_LINE_COMMENT_SCHEMA: Schema = StringSchema::new("Comment (singl
     .format(&SINGLE_LINE_COMMENT_FORMAT)
     .schema();
 
+pub const MULTI_LINE_COMMENT_FORMAT: ApiStringFormat =
+    ApiStringFormat::Pattern(&MULTI_LINE_COMMENT_REGEX);
+
+pub const MULTI_LINE_COMMENT_SCHEMA: Schema = StringSchema::new("Comment (multiple lines).")
+    .format(&MULTI_LINE_COMMENT_FORMAT)
+    .schema();
+
 pub const SUBSCRIPTION_KEY_SCHEMA: Schema = StringSchema::new("Proxmox Backup Server subscription key.")
     .format(&SUBSCRIPTION_KEY_FORMAT)
     .min_length(15)
diff --git a/src/config/node.rs b/src/config/node.rs
index 9ca44a52..bb915f94 100644
--- a/src/config/node.rs
+++ b/src/config/node.rs
@@ -9,7 +9,7 @@ use proxmox_schema::{api, ApiStringFormat, ApiType, Updater};
 use proxmox_http::ProxyConfig;
 
 use pbs_api_types::{EMAIL_SCHEMA, OPENSSL_CIPHERS_TLS_1_2_SCHEMA, OPENSSL_CIPHERS_TLS_1_3_SCHEMA,
-    SINGLE_LINE_COMMENT_SCHEMA};
+    MULTI_LINE_COMMENT_SCHEMA};
 use pbs_buildcfg::configdir;
 use pbs_config::{open_backup_lockfile, BackupLockGuard};
 
@@ -171,7 +171,7 @@ pub enum Translation {
         },
         "comment" : {
             optional: true,
-            schema: SINGLE_LINE_COMMENT_SCHEMA,
+            schema: MULTI_LINE_COMMENT_SCHEMA,
         }
     },
 )]
diff --git a/src/tools/config.rs b/src/tools/config.rs
index f666a8ab..738ab541 100644
--- a/src/tools/config.rs
+++ b/src/tools/config.rs
@@ -32,6 +32,20 @@ pub fn value_from_str(input: &str, schema: &'static Schema) -> Result<Value, Err
 
     let mut config = Object::new();
 
+    // parse first n lines starting with '#' as multi-line comment
+    let comment = input.lines()
+        .take_while(|l| l.starts_with('#'))
+        .map(|l| {
+            let mut ch = l.chars();
+            ch.next();
+            ch.as_str()
+        })
+        .fold(String::new(), |acc, l| acc + l + "\n");
+
+    if !comment.is_empty() {
+        config.insert("comment".to_string(), Value::String(comment));
+    }
+
     for (lineno, line) in input.lines().enumerate() {
         let line = line.trim();
         if line.starts_with('#') || line.is_empty() {
@@ -133,10 +147,23 @@ pub fn value_to_bytes(value: &Value, schema: &'static Schema) -> Result<Vec<u8>,
 
 /// 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 `comment` for multi-line notes
+    if object.contains_key("comment") {
+        let comment = match object.get("comment") {
+            Some(Value::String(v)) => v,
+            _ => bail!("only strings can be comments"),
+        };
+
+        for lines in comment.lines() {
+            writeln!(output, "#{}", lines)?;
+        }
+    }
+
     for (key, value) in object.iter() {
         match value {
             Value::Null => continue, // delete this entry
             Value::Bool(v) => writeln!(output, "{}: {}", key, v)?,
+            Value::String(_) if key == "comment" => continue, // skip comment as we handle it above
             Value::String(v) => {
                 if v.as_bytes().contains(&b'\n') {
                     bail!("value for {} contains newlines", key);
@@ -172,3 +199,38 @@ fn test() {
 
     assert_eq!(config, NODE_CONFIG.as_bytes());
 }
+
+#[test]
+fn test_with_comment() {
+    use proxmox_schema::ApiType;
+
+    // let's just reuse some schema we actually have available:
+    use crate::config::node::NodeConfig;
+
+    const NODE_INPUT: &str = "\
+        #this should\n\
+        #be included\n\
+        acme: account=pebble\n\
+        # this should not\n\
+        acmedomain0: test1.invalid.local,plugin=power\n\
+        acmedomain1: test2.invalid.local\n\
+    ";
+
+    const NODE_OUTPUT: &str = "\
+        #this should\n\
+        #be included\n\
+        acme: account=pebble\n\
+        acmedomain0: test1.invalid.local,plugin=power\n\
+        acmedomain1: test2.invalid.local\n\
+    ";
+
+    let data: NodeConfig = from_str(NODE_INPUT, &NodeConfig::API_SCHEMA)
+        .expect("failed to parse multi-line notes node config");
+
+    println!("{}", data.comment.as_ref().expect("no comment was parsed"));
+
+    let config = to_bytes(&data, &NodeConfig::API_SCHEMA)
+        .expect("failed to serialize multi-line notes node config");
+
+    assert_eq!(config, NODE_OUTPUT.as_bytes());
+}
-- 
2.30.2