archival: pull out adjacent segment run

There's some business logic in archival/types to generate path names. In
the effort to change how we assign paths to objects, this moves that
musiness logical out of archival/types, so that the business logic
doesn't need to muddy such a fundamental file.

src/v/archival/adjacent_segment_run.cc

@@ -0,0 +1,103 @@
+// Copyright 2024 Redpanda Data, Inc.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.md
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0
+#include "archival/adjacent_segment_run.h"
+
+#include "archival/logger.h"
+#include "base/vlog.h"
+#include "cloud_storage/partition_manifest.h"
+#include "cloud_storage/types.h"
+#include "model/metadata.h"
+
+#include <vector>
+
+namespace archival {
+
+bool adjacent_segment_run::maybe_add_segment(
+  const cloud_storage::segment_meta& s, size_t max_size) {
+    vlog(
+      archival_log.debug,
+      "{} Segments collected, looking at segment meta: {}, current run meta: "
+      "{}",
+      num_segments,
+      s,
+      meta);
+    if (num_segments == 1 && meta.size_bytes + s.size_bytes > max_size) {
+        // Corner case, we hit a segment which is smaller than the max_size
+        // but it's larger than max_size when combined with its neighbor. In
+        // this case we need to skip previous the segment.
+        num_segments = 0;
+        segments.clear();
+        meta = {};
+    }
+    if (num_segments == 0) {
+        // Find the begining of the small segment
+        // run.
+        if (s.size_bytes < max_size) {
+            meta = s;
+            num_segments = 1;
+            segments.push_back(
+              cloud_storage::partition_manifest::generate_remote_segment_path(
+                ntp, s));
+        }
+    } else {
+        if (
+          meta.segment_term == s.segment_term
+          && meta.size_bytes + s.size_bytes <= max_size) {
+            // Cross term merging is disallowed. Because of that we need to stop
+            // if the term doesn't match the previous term.
+            if (model::next_offset(meta.committed_offset) != s.base_offset) {
+                // In case if we're dealing with one of the old manifests
+                // with inconsistencies (overlapping offsets, etc).
+                num_segments = 0;
+                meta = {};
+                segments.clear();
+                vlog(
+                  archival_log.debug,
+                  "Reseting the upload, current committed offset: {}, next "
+                  "base offset: {}, meta: {}",
+                  meta.committed_offset,
+                  s.base_offset,
+                  meta);
+                return false;
+            }
+            // Move the end of the small segment run forward
+            meta.committed_offset = s.committed_offset;
+            meta.max_timestamp = s.max_timestamp;
+            num_segments++;
+            meta.size_bytes += s.size_bytes;
+            segments.push_back(
+              cloud_storage::partition_manifest::generate_remote_segment_path(
+                ntp, s));
+        } else {
+            return num_segments > 1;
+        }
+    }
+    return false;
+}
+
+std::ostream& operator<<(std::ostream& os, const adjacent_segment_run& run) {
+    std::vector<ss::sstring> names;
+    names.reserve(run.segments.size());
+    std::transform(
+      run.segments.begin(),
+      run.segments.end(),
+      std::back_inserter(names),
+      [](const cloud_storage::remote_segment_path& rsp) {
+          return rsp().native();
+      });
+    fmt::print(
+      os,
+      "{{meta: {}, num_segments: {}, segments: {}}}",
+      run.meta,
+      run.num_segments,
+      names);
+    return os;
+}
+
+} // namespace archival

src/v/archival/adjacent_segment_run.h

@@ -0,0 +1,46 @@
+// Copyright 2024 Redpanda Data, Inc.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.md
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0
+#pragma once
+
+#include "cloud_storage/types.h"
+#include "model/metadata.h"
+
+#include <vector>
+
+namespace archival {
+
+/// Represents a series of adjacent segments
+/// The object is used to compute a possible reupload
+/// candidate. The series of segment is supposed to be
+/// merged and reuploaded. The object produces metadata
+/// for the reuploaded segment.
+struct adjacent_segment_run {
+    explicit adjacent_segment_run(model::ntp ntp)
+      : ntp(std::move(ntp)) {}
+
+    model::ntp ntp;
+    cloud_storage::segment_meta meta{};
+    size_t num_segments{0};
+    std::vector<cloud_storage::remote_segment_path> segments;
+
+    /// Try to add segment to the run
+    ///
+    /// The subsequent calls are successful until the total size
+    /// of the run is below the threshold. The object keeps track
+    /// of all segment names.
+    ///
+    /// \return true if the run is assembled, false if more segments can be
+    ///         added to the run
+    bool
+    maybe_add_segment(const cloud_storage::segment_meta& s, size_t max_size);
+};
+
+std::ostream& operator<<(std::ostream& o, const adjacent_segment_run& run);
+
+} // namespace archival

src/v/archival/types.cc

@@ -121,86 +121,4 @@ get_archival_service_config(ss::scheduling_group sg, ss::io_priority_class p) {
     return cfg;
 }
 
-bool adjacent_segment_run::maybe_add_segment(
-  const cloud_storage::segment_meta& s, size_t max_size) {
-    vlog(
-      archival_log.debug,
-      "{} Segments collected, looking at segment meta: {}, current run meta: "
-      "{}",
-      num_segments,
-      s,
-      meta);
-    if (num_segments == 1 && meta.size_bytes + s.size_bytes > max_size) {
-        // Corner case, we hit a segment which is smaller than the max_size
-        // but it's larger than max_size when combined with its neighbor. In
-        // this case we need to skip previous the segment.
-        num_segments = 0;
-        segments.clear();
-        meta = {};
-    }
-    if (num_segments == 0) {
-        // Find the begining of the small segment
-        // run.
-        if (s.size_bytes < max_size) {
-            meta = s;
-            num_segments = 1;
-            segments.push_back(
-              cloud_storage::partition_manifest::generate_remote_segment_path(
-                ntp, s));
-        }
-    } else {
-        if (
-          meta.segment_term == s.segment_term
-          && meta.size_bytes + s.size_bytes <= max_size) {
-            // Cross term merging is disallowed. Because of that we need to stop
-            // if the term doesn't match the previous term.
-            if (model::next_offset(meta.committed_offset) != s.base_offset) {
-                // In case if we're dealing with one of the old manifests
-                // with inconsistencies (overlapping offsets, etc).
-                num_segments = 0;
-                meta = {};
-                segments.clear();
-                vlog(
-                  archival_log.debug,
-                  "Reseting the upload, current committed offset: {}, next "
-                  "base offset: {}, meta: {}",
-                  meta.committed_offset,
-                  s.base_offset,
-                  meta);
-                return false;
-            }
-            // Move the end of the small segment run forward
-            meta.committed_offset = s.committed_offset;
-            meta.max_timestamp = s.max_timestamp;
-            num_segments++;
-            meta.size_bytes += s.size_bytes;
-            segments.push_back(
-              cloud_storage::partition_manifest::generate_remote_segment_path(
-                ntp, s));
-        } else {
-            return num_segments > 1;
-        }
-    }
-    return false;
-}
-
-std::ostream& operator<<(std::ostream& os, const adjacent_segment_run& run) {
-    std::vector<ss::sstring> names;
-    names.reserve(run.segments.size());
-    std::transform(
-      run.segments.begin(),
-      run.segments.end(),
-      std::back_inserter(names),
-      [](const cloud_storage::remote_segment_path& rsp) {
-          return rsp().native();
-      });
-    fmt::print(
-      os,
-      "{{meta: {}, num_segments: {}, segments: {}}}",
-      run.meta,
-      run.num_segments,
-      names);
-    return os;
-}
-
 } // namespace archival

src/v/archival/types.h

@@ -10,6 +10,7 @@
 
 #pragma once
 
+#include "archival/adjacent_segment_run.h"
 #include "base/seastarx.h"
 #include "cloud_storage/types.h"
 #include "seastar/core/lowres_clock.hh"
@@ -171,34 +172,6 @@ class housekeeping_job {
 /// Number of segment reuploads the job can do per housekeeping run
 static constexpr int max_reuploads_per_run = 4;
 
-/// Represents a series of adjacent segments
-/// The object is used to compute a possible reupload
-/// candidate. The series of segment is supposed to be
-/// merged and reuploaded. The object produces metadata
-/// for the reuploaded segment.
-struct adjacent_segment_run {
-    explicit adjacent_segment_run(model::ntp ntp)
-      : ntp(std::move(ntp)) {}
-
-    model::ntp ntp;
-    cloud_storage::segment_meta meta{};
-    size_t num_segments{0};
-    std::vector<cloud_storage::remote_segment_path> segments;
-
-    /// Try to add segment to the run
-    ///
-    /// The subsequent calls are successful until the total size
-    /// of the run is below the threshold. The object keeps track
-    /// of all segment names.
-    ///
-    /// \return true if the run is assembled, false if more segments can be
-    ///         added to the run
-    bool
-    maybe_add_segment(const cloud_storage::segment_meta& s, size_t max_size);
-};
-
-std::ostream& operator<<(std::ostream& o, const adjacent_segment_run& run);
-
 enum class error_outcome {
     unexpected_failure = 1,
     timed_out,

src/v/cluster/CMakeLists.txt

@@ -212,6 +212,7 @@ v_cc_library(
     ../archival/retention_calculator.cc
     ../archival/upload_housekeeping_service.cc
     ../archival/adjacent_segment_merger.cc
+    ../archival/adjacent_segment_run.cc
     ../archival/purger.cc
     ../archival/scrubber.cc
     ../archival/archiver_manager.cc