chore: add jit package conditionally to standard images (#311)

Ensure recommended PostgreSQL packages are included in the  
`standard` image only when required by the version. Starting  
with PostgreSQL 18, the PGDG Debian packages split `jit` into  
its own package, so it needs to be added separately.

Closes #288

Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
Signed-off-by: Niccolò Fei <niccolo.fei@enterprisedb.com>
Co-authored-by: Niccolò Fei <niccolo.fei@enterprisedb.com>

Dockerfile

@@ -22,9 +22,10 @@ USER 26
 
 FROM minimal AS standard
 ARG EXTENSIONS
+ARG STANDARD_ADDITIONAL_POSTGRES_PACKAGES
 USER root
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends locales-all ${EXTENSIONS} && \
+    apt-get install -y --no-install-recommends locales-all ${STANDARD_ADDITIONAL_POSTGRES_PACKAGES} ${EXTENSIONS} && \
     apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false && \
     rm -rf /var/lib/apt/lists/* /var/cache/* /var/log/*
 

docker-bake.hcl

@@ -40,6 +40,7 @@ postgreSQLPreviewVersions = [
 # renovate: datasource=github-releases depName=EnterpriseDB/barman versioning=loose
 barmanVersion = "3.14.0"
 
+// Extensions to be included in the `standard` image
 extensions = [
   "pgaudit",
   "pgvector",
@@ -82,6 +83,7 @@ target "default" {
     PG_MAJOR = "${getMajor(pgVersion)}"
     BASE = "${base}"
     EXTENSIONS = "${getExtensionsString(pgVersion, extensions)}"
+    STANDARD_ADDITIONAL_POSTGRES_PACKAGES = "${getStandardAdditionalPostgresPackagesPerMajorVersion(getMajor(pgVersion))}"
     BARMAN_VERSION = "${barmanVersion}"
   }
   attest = [
@@ -155,6 +157,17 @@ function getExtensionsString {
     result = (isPreview(version) == true) ? "" : join(" ", formatlist("postgresql-%s-%s", getMajor(version), extensions))
 }
 
+// This function conditionally adds recommended PostgreSQL packages based on
+// the version. For example, starting with version 18, PGDG moved `jit` out of
+// the main package and into a separate one.
+function getStandardAdditionalPostgresPackagesPerMajorVersion {
+    params = [ majorVersion ]
+    // Add PostgreSQL jit package from version 18
+    result = join(" ", [
+      majorVersion < 18 ? "" : format("postgresql-%s-jit", majorVersion)
+    ])
+}
+
 function isMajorPresent {
   params = [major, pgVersions]
   result = contains([for v in pgVersions : getMajor(v)], major)