Implement functionality in order to generate report directly from the artifacts folder.

report_generator/commands/generate.py

@@ -1,4 +1,9 @@
-"""report_generator generate command."""
+"""The two ways to ask for a report: out of the store, or out of a folder.
+
+Two commands rather than one with a mode switch, because the two need different things and a
+command that demands a database host in order to read a directory is a command nobody will use for
+that. What they share is everything after the artifacts are in hand, which is :func:`_report`.
+"""
 
 from pathlib import Path
 from uuid import UUID
@@ -7,10 +12,12 @@ from pydantic import BaseModel, Field
 
 from cc_common.api import PipelineError, context
 from cc_common.utils import print
+
+# Imported for the properties model; the store half of the tool is the only part that needs it.
 from persistent_storage.shared import StorageConfiguration
 
 from ..rendering import render
-from ..sources import collect
+from ..sources import ReportSources, collect, collect_from_directory
 
 # Where the report goes when the caller names no path.
 DEFAULT_DIRECTORY = Path("reports")
@@ -20,7 +27,7 @@ class GenerateProperties(BaseModel):
     """Configuration properties for the generate CLI command.
 
     Attributes:
-        scan_id: The scan to report on.
+        scan_id: The scan to report on. The store is keyed by it.
         path: Where to write the PDF. A directory is written into under the name
             the renderer chose; leaving it out writes into ``reports/``.
         storage_config: The store the scan's artifacts are read from.
@@ -31,6 +38,23 @@ class GenerateProperties(BaseModel):
     storage_config: StorageConfiguration
 
 
+class FolderProperties(BaseModel):
+    """Configuration properties for the from-folder CLI command.
+
+    Attributes:
+        artifacts: The folder holding the artifacts, as the pipeline exported them.
+        scan_id: The scan to report under. Read out of the artifacts when not
+            given -- an export names its own run.
+        path: Where to write the PDF, as above.
+    """
+
+    artifacts: Path = Field(description="Folder of exported artifacts to build the report from.")
+    scan_id: UUID | None = Field(
+        default=None, description="The scan to report under. Read from the artifacts when omitted."
+    )
+    path: Path | None = Field(default=None, description="Where to write the PDF report.")
+
+
 class GeneratedReport(BaseModel):
     """The report that was written.
 
@@ -51,10 +75,10 @@ class GeneratedReport(BaseModel):
 
 
 def generate(properties: GenerateProperties) -> GeneratedReport:
-    """Build the PDF report of one scan and write it.
+    """Build the report of a scan held in the store.
 
     Args:
-        properties: Parsed command properties naming the scan and the destination.
+        properties: The scan, the store and the destination.
 
     Returns:
         The report that was written.
@@ -63,9 +87,45 @@ def generate(properties: GenerateProperties) -> GeneratedReport:
         PipelineError: The scan cannot be read, is missing an input the report
             needs, or the destination cannot be written.
     """
-    sources = collect(properties.storage_config, properties.scan_id)
+    return _report(collect(properties.storage_config, properties.scan_id), properties.path)
+
+
+def from_folder(properties: FolderProperties) -> GeneratedReport:
+    """Build the report of a scan that was exported to a folder.
+
+    Neither Postgres nor the bucket is touched. The same report, from a directory somebody was sent.
+
+    Args:
+        properties: The folder, optionally the scan to report under, and the destination.
+
+    Returns:
+        The report that was written.
+
+    Raises:
+        PipelineError: The folder cannot be read, names no scan, is missing an
+            input the report needs, or the destination cannot be written.
+    """
+    return _report(collect_from_directory(properties.artifacts, properties.scan_id), properties.path)
+
+
+def _report(sources: ReportSources, path: Path | None) -> GeneratedReport:
+    """Render the collected artifacts and write the result.
+
+    Everything after the artifacts are in hand, which is the same whichever of the two collected
+    them -- and the reason the two commands are two callbacks rather than two pipelines.
+
+    Args:
+        sources: The scan and its files.
+        path: Where the caller asked for the PDF, if anywhere in particular.
+
+    Returns:
+        The report that was written.
+
+    Raises:
+        PipelineError: The report cannot be built or the destination not written.
+    """
     name, content = render(sources)
-    destination = _destination(properties.path, name)
+    destination = _destination(path, name)
 
     try:
         destination.parent.mkdir(parents=True, exist_ok=True)