outputs/postgresql: change config param use_uint8 to uint64_type

In the future, there might be other options for handling uint8 types (e.g. using doubles). This change makes the config forward-compatible for such options.

plugins/outputs/postgresql/Dockerfile

@@ -0,0 +1,26 @@
+# This Dockerfile can be used to build an image including the pguint extension.
+#
+#   docker build -t postgres:pguint .
+#   docker run -d -t postgres -p 5432:5432 -e POSTGRES_HOST_AUTH_METHOD=trust postgres:pguint
+#   docker logs -f postgres 2>&1 | grep -q 'listening on IPv4 address "0.0.0.0", port 5432'
+#   go test -v
+
+# Tag from https://hub.docker.com/_/postgres?tab=tags
+ARG POSTGRES_TAG=latest
+
+ARG PGUINT_REPO
+ARG PGUINT_RELEASE
+
+FROM postgres:${POSTGRES_TAG}
+
+RUN apt-get update && apt-get install -y build-essential curl postgresql-server-dev-${PG_MAJOR}=${PG_VERSION}
+
+ENV PGUINT_REPO=${PGUINT_REPO:-phemmer/pguint}
+ENV PGUINT_REF=${PGUINT_REF:-fix-getmsgint64}
+RUN mkdir /pguint && cd /pguint && \
+    curl -L https://github.com/${PGUINT_REPO}/tarball/${PGUINT_REF} | tar -zx --strip-components=1 && \
+    make && make install && \
+    echo 'CREATE EXTENSION uint;' > /docker-entrypoint-initdb.d/uint.sql && \
+    echo '\\c template1' >> /docker-entrypoint-initdb.d/uint.sql && \
+    echo 'CREATE EXTENSION uint;' >> /docker-entrypoint-initdb.d/uint.sql
+

plugins/outputs/postgresql/README.md

@@ -67,8 +67,12 @@ The plugin manages the schema, automatically updating missing columns.
   #   '''ALTER TABLE {{.table}} ADD COLUMN IF NOT EXISTS {{.columns|join ", ADD COLUMN IF NOT EXISTS "}}''',
   # ]
 
-  ## Controls whether to use the uint8 data type provided by the pguint extension.
-  # use_uint8 = false
+  ## The postgres data type to use for storing unsigned 64-bit integer values as Postgres does not have a native
+  ## unsigned 64-bit integer type.
+  ## The value can be one of:
+  ##   numeric - Uses the PostgreSQL "numeric" data type.
+  ##   uint8 - Requires pguint extension (https://github.com/petere/pguint)
+  # uint64_type = "numeric"
 
   ## When using pool_max_conns>1, and a temporary error occurs, the query is retried with an incremental backoff. This
   ## controls the maximum backoff duration.

plugins/outputs/postgresql/datatypes.go

@@ -29,7 +29,7 @@ const (
 // DerivePgDatatype returns the appropriate PostgreSQL data type
 // that could hold the value.
 func (p *Postgresql) derivePgDatatype(value interface{}) string {
-	if p.UseUint8 {
+	if p.Uint64Type == PgUint8 {
 		if _, ok := value.(uint64); ok {
 			return PgUint8
 		}

plugins/outputs/postgresql/postgresql.go

@@ -89,8 +89,12 @@ var sampleConfig = `
   #   '''ALTER TABLE {{.table}} ADD COLUMN IF NOT EXISTS {{.columns|join ", ADD COLUMN IF NOT EXISTS "}}''',
   # ]
 
-  ## Controls whether to use the uint8 data type provided by the pguint extension.
-  # use_uint8 = false
+  ## The postgres data type to use for storing unsigned 64-bit integer values as Postgres does not have a native
+  ## unsigned 64-bit integer type.
+  ## The value can be one of:
+  ##   numeric - Uses the PostgreSQL "numeric" data type.
+  ##   uint8 - Requires pguint extension (https://github.com/petere/pguint)
+  # uint64_type = "numeric"
 
   ## When using pool_max_conns>1, and a temporary error occurs, the query is retried with an incremental backoff. This
   ## controls the maximum backoff duration.
@@ -117,7 +121,7 @@ type Postgresql struct {
 	AddColumnTemplates         []*sqltemplate.Template `toml:"add_column_templates"`
 	TagTableCreateTemplates    []*sqltemplate.Template `toml:"tag_table_create_templates"`
 	TagTableAddColumnTemplates []*sqltemplate.Template `toml:"tag_table_add_column_templates"`
-	UseUint8                   bool                    `toml:"use_uint8"`
+	Uint64Type                 string                  `toml:"uint64_type"`
 	RetryMaxBackoff            config.Duration         `toml:"retry_max_backoff"`
 	TagCacheSize               int                     `toml:"tag_cache_size"`
 	LogLevel                   string                  `toml:"log_level"`
@@ -223,8 +227,15 @@ func (p *Postgresql) Init() error {
 		}
 	}
 
-	if p.UseUint8 {
+	switch p.Uint64Type {
+	case "":
+		p.Uint64Type = PgNumeric
+		fallthrough
+	case PgNumeric:
+	case PgUint8:
 		p.dbConfig.AfterConnect = p.registerUint8
+	default:
+		return fmt.Errorf("invalid uint64_type")
 	}
 
 	return nil

plugins/outputs/postgresql/postgresql_test.go

@@ -717,7 +717,7 @@ func TestWrite_utf8(t *testing.T) {
 
 func TestWrite_UnsignedIntegers(t *testing.T) {
 	p := newPostgresqlTest(t)
-	p.UseUint8 = true
+	p.Uint64Type = PgUint8
 	_ = p.Init()
 	if err := p.Connect(); err != nil {
 		if strings.Contains(err.Error(), "retreiving OID for uint8 data type") {

plugins/outputs/postgresql/table_manager_test.go

@@ -195,7 +195,7 @@ func TestTableManager_MatchSource(t *testing.T) {
 
 func TestTableManager_MatchSource_UnsignedIntegers(t *testing.T) {
 	p := newPostgresqlTest(t)
-	p.UseUint8 = true
+	p.Uint64Type = PgUint8
 	_ = p.Init()
 	if err := p.Connect(); err != nil {
 		if strings.Contains(err.Error(), "retreiving OID for uint8 data type") {