Enhance the tedge_apt_plugin error message to be more verbose (#1341)

* Enhance the error message to be more precise

Signed-off-by: Pradeep Kumar K J <pradeepkumar.kj@softwareag.com>

3 files changed, 51 insertions, 35 deletions

diff --git a/plugins/tedge_apt_plugin/src/error.rs b/plugins/tedge_apt_plugin/src/error.rs
index 07c8399a..c9332cf3 100644
--- a/plugins/tedge_apt_plugin/src/error.rs
+++ b/plugins/tedge_apt_plugin/src/error.rs
@@ -9,17 +9,18 @@ pub enum InternalError {
     #[error(transparent)]
     FromUtf8(#[from] std::string::FromUtf8Error),
 
-    #[error("Parsing Debian package failed for `{file}`")]
-    ParsingError { file: String },
-
     #[error(transparent)]
     FromCsv(#[from] csv::Error),
 
-    #[error("Validation of {package} failed with version mismatch. Installed version: {installed}, Expected version: {expected}")]
-    VersionMismatch {
+    #[error("Parsing Debian package failed for `{file}`, Error: {error}")]
+    ParsingError { file: String, error: String },
+
+    #[error("Validation of {package} metadata failed, expected value for the {expected_key} is {expected_value}, but provided {provided_value}")]
+    MetaDataMismatch {
         package: String,
-        installed: String,
-        expected: String,
+        expected_key: String,
+        expected_value: String,
+        provided_value: String,
     },
 }
 
diff --git a/plugins/tedge_apt_plugin/src/main.rs b/plugins/tedge_apt_plugin/src/main.rs
index 5d503aeb..8fada405 100644
--- a/plugins/tedge_apt_plugin/src/main.rs
+++ b/plugins/tedge_apt_plugin/src/main.rs
@@ -207,10 +207,11 @@ fn validate_version(module_name: &str, module_version: &str) -> Result<(), Inter
         // Value at index 0 is the package name
         {
             if installed_version != module_version {
-                return Err(InternalError::VersionMismatch {
+                return Err(InternalError::MetaDataMismatch {
                     package: module_name.into(),
-                    installed: installed_version.into(),
-                    expected: module_version.into(),
+                    expected_key: "Version".into(),
+                    expected_value: installed_version.into(),
+                    provided_value: module_version.into(),
                 });
             }
         }
diff --git a/plugins/tedge_apt_plugin/src/module_check.rs b/plugins/tedge_apt_plugin/src/module_check.rs
index ecb20497..69ccb84e 100644
--- a/plugins/tedge_apt_plugin/src/module_check.rs
+++ b/plugins/tedge_apt_plugin/src/module_check.rs
@@ -1,5 +1,5 @@
 use crate::error::InternalError;
-use std::process::{Command, Stdio};
+use std::process::Command;
 use std::{
     ffi::OsStr,
     path::{Path, PathBuf},
@@ -22,41 +22,55 @@ impl PackageMetadata {
         })
     }
 
-    fn metadata_contains_all(&self, patterns: &[&str]) -> bool {
+    fn metadata_contains_all(&self, patterns: &[&str]) -> Result<(), InternalError> {
         for pattern in patterns {
             if !&self.metadata.contains(pattern) {
-                return false;
-            };
+                let given_metadata_split: Vec<&str> = pattern.split(':').collect();
+                // Extract the expected meta data value for the given key
+                // For example Package name, Version etc.
+                let expected_metadata_split: Vec<&str> = self
+                    .metadata
+                    .split(&given_metadata_split[0])
+                    .collect::<Vec<&str>>()[1]
+                    .split('\n')
+                    .collect::<Vec<&str>>()[0]
+                    .split(':')
+                    .collect();
+
+                return Err(InternalError::MetaDataMismatch {
+                    package: self.file_path().to_string_lossy().to_string(),
+                    expected_key: given_metadata_split[0].to_string(),
+                    expected_value: expected_metadata_split[1].to_string(),
+                    provided_value: given_metadata_split[1].to_string(),
+                });
+            }
         }
-        true
+        Ok(())
     }
 
     fn get_module_metadata(file_path: &str) -> Result<Vec<u8>, InternalError> {
-        Ok(Command::new("dpkg")
-            .arg("-I")
-            .arg(file_path)
-            .stdout(Stdio::piped())
-            .output()?
-            .stdout)
+        let res = Command::new("dpkg").arg("-I").arg(file_path).output()?;
+        match res.status.success() {
+            true => Ok(res.stdout),
+            false => Err(InternalError::ParsingError {
+                file: file_path.to_string(),
+                error: String::from_utf8_lossy(&res.stderr).to_string(),
+            }),
+        }
     }
 
     pub fn validate_package(&mut self, contain_args: &[&str]) -> Result<(), InternalError> {
-        if self.metadata_contains_all(contain_args) {
-            // In the current implementation using `apt-get` it is required that the file has '.deb' extension (if we use dpkg extension doesn't matter).
-            if self.file_path.extension() != Some(OsStr::new("deb")) {
-                let new_path = PathBuf::from(format!("{}.deb", self.file_path().to_string_lossy()));
+        self.metadata_contains_all(contain_args)?;
+        // In the current implementation using `apt-get` it is required that the file has '.deb' extension (if we use dpkg extension doesn't matter).
+        if self.file_path.extension() != Some(OsStr::new("deb")) {
+            let new_path = PathBuf::from(format!("{}.deb", self.file_path().to_string_lossy()));
 
-                let _res = std::os::unix::fs::symlink(self.file_path(), &new_path);
-                self.file_path = new_path;
-                self.remove_modified = true;
-            }
-
-            Ok(())
-        } else {
-            Err(InternalError::ParsingError {
-                file: self.file_path().to_string_lossy().to_string(),
-            })
+            let _res = std::os::unix::fs::symlink(self.file_path(), &new_path);
+            self.file_path = new_path;
+            self.remove_modified = true;
         }
+
+        Ok(())
     }
 
     pub fn file_path(&self) -> &Path {