From 63f82f7fe85afc5f126d3b3366d07305d0c4e8d5 Mon Sep 17 00:00:00 2001
From: Conor Nosal <cnosal@vmware.com>
Date: Fri, 9 Jun 2023 12:13:31 -0700
Subject: [PATCH] Add source.tag_regex

Match arbitrary tags. Takes precendence over pre_releases.

Signed-off-by: Conor Nosal <cnosal@vmware.com>
---
 README.md         |  9 ++++++++
 check_test.go     | 57 +++++++++++++++++++++++++++++++++++++++++++++++
 commands/check.go | 55 ++++++++++++++++++++++++++++-----------------
 types.go          |  1 +
 4 files changed, 102 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index bb6c09f..c5c2318 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,15 @@ differences:
     on digest).
     </td>
   </tr>
+  <tr>
+    <td><code>tag_regex</code> <em>(Optional)</em></td>
+    <td>
+    Monitor semver tags that match the provided regular expression.
+    Results are sorted in semver order.
+    <br>
+    Takes precedence over <code>pre_releases</code>
+    </td>
+  </tr>
   <tr>
     <td><code>variant</code> <em>(Optional)</em></td>
     <td>
diff --git a/check_test.go b/check_test.go
index 6224522..15ef1d6 100644
--- a/check_test.go
+++ b/check_test.go
@@ -1111,6 +1111,60 @@ var _ = DescribeTable("tracking semver tags",
 			Versions: []string{"1.0.0", "1.2.1", "2.0.0"},
 		},
 	),
+	Entry("tag regex for final versions",
+		SemverTagCheckExample{
+			Tags: map[string]string{
+				"1.0.0":         "random-1",
+				"1.0.0-alpha.1": "random-2",
+				"1.2.1":         "random-3",
+				"2.0.0":         "random-5",
+			},
+
+			TagRegex: "^[0-9].[0-9].[0-9]$",
+
+			Versions: []string{
+				"1.0.0",
+				"1.2.1",
+				"2.0.0",
+			},
+		},
+	),
+	Entry("tag regex for arbitrary prerelease",
+		SemverTagCheckExample{
+			Tags: map[string]string{
+				"1.0.0":         "random-1",
+				"1.0.0-alpha.1": "random-2",
+				"1.2.0-dev.1-built.123": "random-3",
+				"1.2.1":         "random-4",
+				"2.0.0":         "random-5",
+			},
+
+			TagRegex: "^[0-9]\\.[0-9]\\.[0-9]-dev\\.[0-9]+.built\\.[0-9]+$",
+
+			Versions: []string{
+				"1.2.0-dev.1-built.123",
+			},
+		},
+	),
+	Entry("combine tag regex, semver constraint, and variant",
+		SemverTagCheckExample{
+			Tags: map[string]string{
+				"1.1.0-dev.1-built.123-foo": "random-1",
+				"1.2.0-dev.1-built.123-foo": "random-2",
+				"1.3.0-dev.1-built.123-foo": "random-3",
+				"1.3.0-dev.1-built.123-bar": "random-4",
+			},
+
+			TagRegex: "^[0-9]\\.[0-9]\\.[0-9]-dev\\.[0-9]+.built\\.[0-9]+.*$",
+			Variant: "foo",
+			SemverConstraint: ">= 1.2.0-0",
+
+			Versions: []string{
+				"1.2.0-dev.1-built.123-foo",
+				"1.3.0-dev.1-built.123-foo",
+			},
+		},
+	),
 )
 
 type SemverTagCheckExample struct {
@@ -1122,6 +1176,8 @@ type SemverTagCheckExample struct {
 
 	SemverConstraint string
 
+	TagRegex string
+
 	Repository     string
 	RegistryMirror string
 	WorkingMirror  bool
@@ -1159,6 +1215,7 @@ func (example SemverTagCheckExample) Run() {
 			PreReleasePrefixes: example.PreReleasePrefixes,
 			Variant:            example.Variant,
 			SemverConstraint:   example.SemverConstraint,
+			TagRegex:           example.TagRegex,
 		},
 	}
 
diff --git a/commands/check.go b/commands/check.go
index 49768e6..c5f9192 100644
--- a/commands/check.go
+++ b/commands/check.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"sort"
 	"strings"
+	"regexp"
 
 	"github.com/Masterminds/semver/v3"
 	resource "github.com/concourse/registry-image-resource"
@@ -137,6 +138,14 @@ func checkRepository(repo name.Repository, source resource.Source, from *resourc
 		}
 	}
 
+	var regex *regexp.Regexp
+	if source.TagRegex != "" {
+		regex, err = regexp.Compile(source.TagRegex)
+		if err != nil {
+			return resource.CheckResponse{}, fmt.Errorf("parse tag regex: %w", err)
+		}
+	}
+
 	for _, identifier := range tags {
 		var ver *semver.Version
 		if identifier == bareTag {
@@ -162,32 +171,38 @@ func checkRepository(repo name.Repository, source resource.Source, from *resourc
 				continue
 			}
 
-			pre := ver.Prerelease()
-			if pre != "" {
-				// pre-releases not enabled; skip
-				if !source.PreReleases {
+			if regex != nil {
+				if ! regex.MatchString(identifier) {
 					continue
 				}
-
-				preReleasePrefixes := []string{"alpha", "beta", "rc"}
-				if source.PreReleasePrefixes != nil && len(source.PreReleasePrefixes) > 0 {
-					preReleasePrefixes = append(preReleasePrefixes, source.PreReleasePrefixes...)
-				} else {
-					if strings.Contains(pre, "-") {
-						// contains additional variant
+			} else {
+				pre := ver.Prerelease()
+				if pre != "" {
+					// pre-releases not enabled; skip
+					if !source.PreReleases {
 						continue
 					}
-				}
 
-				match := false
-				for _, prefix := range preReleasePrefixes {
-					if strings.HasPrefix(pre, prefix) {
-						match = true
+					preReleasePrefixes := []string{"alpha", "beta", "rc"}
+					if source.PreReleasePrefixes != nil && len(source.PreReleasePrefixes) > 0 {
+						preReleasePrefixes = append(preReleasePrefixes, source.PreReleasePrefixes...)
+					} else {
+						if strings.Contains(pre, "-") {
+							// contains additional variant
+							continue
+						}
+					}
+
+					match := false
+					for _, prefix := range preReleasePrefixes {
+						if strings.HasPrefix(pre, prefix) {
+							match = true
+						}
+					}
+					if ! match {
+						// additional variant, not a prerelease segment
+						continue
 					}
-				}
-				if ! match {
-					// additional variant, not a prerelease segment
-					continue
 				}
 			}
 
diff --git a/types.go b/types.go
index 2d0d055..d21e1ba 100644
--- a/types.go
+++ b/types.go
@@ -95,6 +95,7 @@ type Source struct {
 	SemverConstraint string `json:"semver_constraint,omitempty"`
 
 	Tag Tag `json:"tag,omitempty"`
+	TagRegex string `json:"tag_regex,omitempty"`
 
 	BasicCredentials
 	AwsCredentials