Better Error Handling and Logging

Summary

Better error handling (less exceptions, more error codes) and logging (for more detailed error handling and configuration issues).

Issue: https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/390

See also the tests in caosdb-cppinttest!2 (merged)

Focus

• The TransactionStatus class represents the current status of a Transaction instance.
• The TransactionCode is a numeric representation of the status and intended for c-compatible error handling.
• Messages and Message classes handle the errors, warnings and info messages that come from the server.
• Logging: The logging can be configured via a json file. Otherwise the default configuration is in place.
• A lot of code was moved in order to comply with -pedantic flag. Don't waste your time

Test Environment

Unit tests should run as described in README_SETUP

Integration tests should run against a linkahead in the f-grpc branch

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

caosdb-client-configuration-schema.json

@@ -24,6 +24,30 @@
         "$ref": "#/definitions/connection_configuration"
       }
     },
+    "logging": {
+      "type": "object",
+      "description": "Configuration of logging",
+      "properties": {
+        "level": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/log_level_configuration"
+            },
+            {
+            "default": "warn",
+            "description": "Global severity filter. Only log messages with at least the given severity are processed by the logging framework. 'off' means that the logging frame work is turned off entirely. Defaults to "
+            }
+          ]
+        },
+        "sinks": {
+          "type": "object",
+          "description": "Configuration of sinks, i.e. the log files, console or other logging frame works where the log messages are supposed to end up eventually.",
+          "additionalProperties": {
+            "$ref": "#/definitions/sink_configuration"
+          }
+        }
+      }
+    },
     "extension": {
       "type": "object",
       "description": "A reserved configuration object which may be used to store additional options for particular clients and special extensions.",
@@ -31,6 +55,58 @@
     }
   },
   "definitions": {
+    "log_level_configuration": {
+      "type": "string",
+      "enum": ["all", "trace", "debug", "info", "warn", "error", "fatal", "off"]
+    },
+    "sink_configuration": {
+      "type": "object",
+      "description": "A single sink configuration.",
+      "additionalProperties": false,
+      "properties": {
+        "level": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/log_level_configuration"
+            },
+            {
+            "description": "Sink severity filter. Only log messages with at least the given severity are passed to this sink. 'off' means that this sink is turned off entirely. Defaults to the global log level."
+            }
+          ]
+        },
+        "destination": {
+          "type": "string",
+          "enum": [ "console", "file", "syslog"],
+          "description": "The type of sink-backend. 'console' writes to the STDERR, 'file' to a text file and 'syslog' uses the syslog API."
+        },
+        "directory": {
+          "type": "string",
+          "description": "Path to local directory. All log files are being stored to this directory. If not specified, the current working directory will be used."
+        },
+        "local_address": {
+          "type": "string",
+          "description": "Local IP address to initiate connection to the syslog server. If not specified, the default local address will be used."
+        },
+        "target_address": {
+          "type": "string",
+          "description": "Remote IP address of the syslog server. If not specified, the local address will be used. "
+        }
+      },
+      "required": [ "destination" ],
+      "allOf": [ {
+          "if": {"properties": {"destination": { "const": "console" } } },
+          "then": {"propertyNames" : { "enum": ["level", "destination"] } }
+        },
+        {
+          "if": {"properties": {"destination": { "const": "file" } } },
+          "then": {"propertyNames" : { "enum": ["level", "destination", "directory"] } }
+        },
+        {
+          "if": {"properties": {"destination": { "const": "syslog" } } },
+          "then": {"propertyNames" : { "enum": ["level", "destination", "target_address", "local_address"] } }
+        }
+      ]
+    },
     "connection_configuration": {
       "type": "object",
       "description": "A single connection configuration.",