Support custom placeholders in templates

src/graphql/mod.rs

@@ -14,6 +14,7 @@
 
 use std::any;
 use std::borrow::Cow;
+use std::collections::HashMap;
 use std::future::Future;
 use std::io::Write;
 use std::path::{Component, PathBuf};
@@ -145,6 +146,7 @@ struct DirectoryPath {
 struct ScanPaths {
     directory: DirectoryPath,
     subdirectory: Subdirectory,
+    metadata: HashMap<String, String>,
 }
 
 /// GraphQL type to provide current configuration for an instrument
@@ -153,6 +155,12 @@ struct CurrentConfiguration {
     high_file: Option<u32>,
 }
 
+#[derive(Debug, InputObject)]
+struct MetaKeyValue {
+    key: String,
+    value: String,
+}
+
 /// Error to be returned when a path contains non-unicode characters
 #[derive(Debug, Display, Error)]
 #[display("Path contains non-unicode characters")]
@@ -308,6 +316,12 @@ impl FieldSource<ScanField> for ScanPaths {
             ScanField::Subdirectory => self.subdirectory.to_string().into(),
             ScanField::ScanNumber => self.directory.info.scan_number().to_string().into(),
             ScanField::Directory(dir) => self.directory.resolve(dir),
+            ScanField::Custom(key) => self
+                .metadata
+                .get(key)
+                .map(|s| s.as_str())
+                .unwrap_or("")
+                .into(),
         }
     }
 }
@@ -397,6 +411,7 @@ impl Mutation {
         instrument: String,
         instrument_session: String,
         sub: Option<Subdirectory>,
+        meta: Option<Vec<MetaKeyValue>>,
     ) -> async_graphql::Result<ScanPaths> {
         check_auth(ctx, |policy, token| {
             policy.check_access(token, &instrument, &instrument_session)
@@ -420,11 +435,18 @@ impl Mutation {
             warn!("Failed to increment tracker file: {e}");
         }
 
+        let metadata = meta
+            .into_iter()
+            .flatten()
+            .map(|kv| (kv.key, kv.value))
+            .collect();
+
         Ok(ScanPaths {
             directory: DirectoryPath {
                 instrument_session,
                 info: next_scan,
             },
+            metadata,
             subdirectory: sub.unwrap_or_default(),
         })
     }

src/paths.rs

@@ -32,17 +32,19 @@ pub enum DirectoryField {
     Instrument,
 }
 
-#[derive(Debug, Display, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Display, Clone, PartialEq, Eq, Hash)]
 pub enum ScanField {
     #[display("subdirectory")]
     Subdirectory,
     #[display("scan_number")]
     ScanNumber,
     #[display("{_0}")]
     Directory(DirectoryField),
+    #[display("{_0}")]
+    Custom(String),
 }
 
-#[derive(Debug, Display, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Display, Clone, PartialEq, Eq, Hash)]
 pub enum DetectorField {
     #[display("detector")]
     Detector,
@@ -73,7 +75,10 @@ impl TryFrom<String> for ScanField {
         match value.as_str() {
             "scan_number" => Ok(ScanField::ScanNumber),
             "subdirectory" => Ok(ScanField::Subdirectory),
-            _ => Ok(ScanField::Directory(DirectoryField::try_from(value)?)),
+            _ => match DirectoryField::try_from(value) {
+                Ok(bf) => Ok(ScanField::Directory(bf)),
+                Err(InvalidKey(value)) => Ok(ScanField::Custom(value)),
+            },
         }
     }
 }
@@ -235,7 +240,6 @@ mod paths_tests {
     #[case::invalid_path_incomplete("data/{unclosed", TemplateErrorType::Incomplete)]
     #[case::invalid_path_empty("data/{}", TemplateErrorType::Empty)]
     #[case::invalid_path_nested("data/{nes{ted}}", TemplateErrorType::Nested)]
-    #[case::invalid_path_unrecognised("data/{detector}", TemplateErrorType::Unrecognised)]
     fn invalid_scan<E: PartialEq<InvalidPathTemplate> + Debug>(
         #[case] template: &str,
         #[case] err: E,
@@ -251,7 +255,6 @@ mod paths_tests {
     #[case::invalid_path_incomplete("data/{unclosed", TemplateErrorType::Incomplete)]
     #[case::invalid_path_empty("data/{}", TemplateErrorType::Empty)]
     #[case::invalid_path_nested("data/{nes{ted}}", TemplateErrorType::Nested)]
-    #[case::invalid_path_unrecognised("data/{unknown}", TemplateErrorType::Unrecognised)]
     fn invalid_detector<E: PartialEq<InvalidPathTemplate> + Debug>(
         #[case] template: &str,
         #[case] err: E,

static/service_schema.graphql

@@ -112,14 +112,19 @@ A template describing the path to the data directory for a given instrument sess
 """
 scalar DirectoryTemplate
 
+input MetaKeyValue {
+	key: String!
+	value: String!
+}
+
 """
 Queries that modify the state of the numtracker configuration in some way
 """
 type Mutation {
 	"""
 	Generate scan file locations for the next scan
 	"""
-	scan(instrument: String!, instrumentSession: String!, sub: Subdirectory): ScanPaths!
+	scan(instrument: String!, instrumentSession: String!, sub: Subdirectory, meta: [MetaKeyValue!]): ScanPaths!
 	"""
 	Add or modify the stored configuration for an instrument
 	"""