From f2f080d43315eb72a4416f22bd13652ff2d01c2b Mon Sep 17 00:00:00 2001
From: Dan Jaglowski <jaglows3@gmail.com>
Date: Tue, 5 Mar 2024 08:53:18 -0600
Subject: [PATCH] [pkg/stanza/fileconsumer] Establish options pattern for Build

---
 .../pkg-stanza-fileconsumer-build-opts.yaml   | 27 +++++++++
 pkg/stanza/fileconsumer/config.go             | 60 +++++++++++--------
 2 files changed, 61 insertions(+), 26 deletions(-)
 create mode 100755 .chloggen/pkg-stanza-fileconsumer-build-opts.yaml

diff --git a/.chloggen/pkg-stanza-fileconsumer-build-opts.yaml b/.chloggen/pkg-stanza-fileconsumer-build-opts.yaml
new file mode 100755
index 0000000000000..49f89c266642c
--- /dev/null
+++ b/.chloggen/pkg-stanza-fileconsumer-build-opts.yaml
@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/stanza
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Deprecate fileconsumer.BuildWithSplitFunc in favor of Build with options pattern
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: []
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]
diff --git a/pkg/stanza/fileconsumer/config.go b/pkg/stanza/fileconsumer/config.go
index ec2a4cd555b7a..1c59dfeed02ed 100644
--- a/pkg/stanza/fileconsumer/config.go
+++ b/pkg/stanza/fileconsumer/config.go
@@ -87,20 +87,35 @@ type HeaderConfig struct {
 	MetadataOperators []operator.Config `mapstructure:"metadata_operators"`
 }
 
-// Build will build a file input operator from the supplied configuration
-func (c Config) Build(logger *zap.SugaredLogger, emit emit.Callback) (*Manager, error) {
+// Deprecated [v0.97.0] Use Build and WithSplitFunc option instead
+func (c Config) BuildWithSplitFunc(logger *zap.SugaredLogger, emit emit.Callback, splitFunc bufio.SplitFunc) (*Manager, error) {
+	return c.Build(logger, emit, WithSplitFunc(splitFunc))
+}
+
+func (c Config) Build(logger *zap.SugaredLogger, emit emit.Callback, opts ...Option) (*Manager, error) {
 	if err := c.validate(); err != nil {
 		return nil, err
 	}
+	if emit == nil {
+		return nil, fmt.Errorf("must provide emit function")
+	}
+
+	o := new(options)
+	for _, opt := range opts {
+		opt(o)
+	}
 
 	enc, err := decode.LookupEncoding(c.Encoding)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to find encoding: %w", err)
 	}
 
-	splitFunc, err := c.SplitConfig.Func(enc, false, int(c.MaxLogSize))
-	if err != nil {
-		return nil, err
+	splitFunc := o.splitFunc
+	if splitFunc == nil {
+		splitFunc, err = c.SplitConfig.Func(enc, false, int(c.MaxLogSize))
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	trimFunc := trim.Nop
@@ -108,21 +123,6 @@ func (c Config) Build(logger *zap.SugaredLogger, emit emit.Callback) (*Manager,
 		trimFunc = c.TrimConfig.Func()
 	}
 
-	return c.buildManager(logger, emit, splitFunc, trimFunc)
-}
-
-// BuildWithSplitFunc will build a file input operator with customized splitFunc function
-func (c Config) BuildWithSplitFunc(logger *zap.SugaredLogger, emit emit.Callback, splitFunc bufio.SplitFunc) (*Manager, error) {
-	if err := c.validate(); err != nil {
-		return nil, err
-	}
-	return c.buildManager(logger, emit, splitFunc, c.TrimConfig.Func())
-}
-
-func (c Config) buildManager(logger *zap.SugaredLogger, emit emit.Callback, splitFunc bufio.SplitFunc, trimFunc trim.Func) (*Manager, error) {
-	if emit == nil {
-		return nil, fmt.Errorf("must provide emit function")
-	}
 	var startAtBeginning bool
 	switch c.StartAt {
 	case "beginning":
@@ -133,11 +133,6 @@ func (c Config) buildManager(logger *zap.SugaredLogger, emit emit.Callback, spli
 		return nil, fmt.Errorf("invalid start_at location '%s'", c.StartAt)
 	}
 
-	enc, err := decode.LookupEncoding(c.Encoding)
-	if err != nil {
-		return nil, fmt.Errorf("failed to find encoding: %w", err)
-	}
-
 	var hCfg *header.Config
 	if c.Header != nil {
 		hCfg, err = header.NewConfig(c.Header.Pattern, c.Header.MetadataOperators, enc)
@@ -232,3 +227,16 @@ func (c Config) validate() error {
 
 	return nil
 }
+
+type options struct {
+	splitFunc bufio.SplitFunc
+}
+
+type Option func(*options)
+
+// WithSplitFunc overrides the split func which is normally built from other settings on the config
+func WithSplitFunc(f bufio.SplitFunc) Option {
+	return func(o *options) {
+		o.splitFunc = f
+	}
+}