Merge pull request #124 from noapinsler/master

adding db auto discovery support to postgres

Author: dewey

job.go

@@ -243,6 +243,49 @@ func (j *Job) updateConnections() {
 				conn = strings.Replace(conn, "AUTHTOKEN", url.QueryEscape(token), 1)
 			}
 
+			if strings.HasPrefix(conn, "postgres://") || strings.HasPrefix(conn, "pg://") {
+				u, err := url.Parse(conn)
+				var filteredDBs []string
+				if err != nil {
+					level.Error(j.log).Log("msg", "Failed to parse URL", "url", conn, "err", err)
+					continue
+				}
+				if strings.Contains(u.Path, "include") || strings.Contains(u.Path, "exclude") {
+					if strings.Contains(u.Path, "include") && strings.Contains(u.Path, "exclude") {
+						level.Error(j.log).Log("msg", "You cannot use exclude and include:", "url", conn, "err", err)
+						return 
+					} else {
+						extractedPath := u.Path //save pattern
+						u.Path = "/postgres"
+						dsn := u.String()
+						databases, err := listDatabases(dsn) 
+						if err != nil {
+							level.Error(j.log).Log("msg", "Error listing databases", "url", conn, "err", err)
+							continue
+						}
+						filteredDBs, err = filterDatabases(databases, extractedPath)
+						if err != nil {
+							level.Error(j.log).Log("msg", "Error filtering databases", "url", conn, "err", err)
+							continue
+						}
+
+						for _, db := range filteredDBs {
+							u.Path = "/" + db // Set the path to the filtered database name
+							newUserDSN := u.String()
+							j.conns = append(j.conns, &connection{
+								conn:     nil, 
+								url:      newUserDSN,
+								driver:   u.Scheme,
+								host:     u.Host,
+								database: db,
+								user:     u.User.Username(),
+							})
+						}
+						continue
+					}
+				}
+			}
+
 			u, err := url.Parse(conn)
 			if err != nil {
 				level.Error(j.log).Log("msg", "Failed to parse URL", "url", conn, "err", err)

postgresql.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"regexp"
+	"strings"
+
+	_ "github.com/lib/pq"
+)
+
+const (
+	INCLUDE_DBS = "/include:"
+	EXCLUDE_DBS = "/exclude:"
+)
+
+func listDatabases(connStr string) ([]string, error) {
+
+	db, err := sql.Open("postgres", connStr)
+	if err != nil {
+		return nil, err
+	}
+	defer db.Close()
+
+	rows, err := db.Query("SELECT datname FROM pg_database WHERE datistemplate = false;")
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var databases []string
+	for rows.Next() {
+		var dbname string
+		if err := rows.Scan(&dbname); err != nil {
+			return nil, err
+		}
+		databases = append(databases, dbname)
+	}
+
+	return databases, nil
+}
+
+func filterDatabases(databases []string, pattern string) ([]string, error) {
+	var filtered []string
+	mode, dbs := parsePattern(pattern)
+
+	// Split the dbs string into individual patterns
+	dbPatterns := strings.Split(dbs, ",")
+
+	// Process each database name against the patterns
+	for _, dbname := range databases {
+		include := false
+
+		for _, dbPattern := range dbPatterns {
+			matched, err := regexp.MatchString(dbPattern, dbname)
+			if err != nil {
+				return nil, fmt.Errorf("invalid pattern: %s", dbPattern)
+			}
+			if matched {
+				include = true
+				break
+			}
+		}
+
+		if (mode == INCLUDE_DBS && include) || (mode == EXCLUDE_DBS && !include) {
+			filtered = append(filtered, dbname)
+		}
+	}
+
+	return filtered, nil
+}
+
+func parsePattern(pattern string) (mode string, dbs string) {
+	if strings.HasPrefix(pattern, INCLUDE_DBS) {
+		return INCLUDE_DBS, pattern[len(INCLUDE_DBS):]
+	} else if strings.HasPrefix(pattern, EXCLUDE_DBS) {
+		return EXCLUDE_DBS, pattern[len(EXCLUDE_DBS):]
+	}
+	return "", ""
+}