Refactor exporter so that it can be used as a library.

collector/postgres_exporter_integration_test.go

@@ -0,0 +1,124 @@
+// These are specialized integration tests. We only build them when we're doing
+// a lot of additional work to keep the external docker environment they require
+// working.
+// +build integration
+
+package collector
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"testing"
+
+	_ "github.com/lib/pq"
+	"github.com/prometheus/client_golang/prometheus"
+	. "gopkg.in/check.v1"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { TestingT(t) }
+
+type IntegrationSuite struct {
+	e *Exporter
+}
+
+var _ = Suite(&IntegrationSuite{})
+
+func (s *IntegrationSuite) SetUpSuite(c *C) {
+	dsn := os.Getenv("DATA_SOURCE_NAME")
+	c.Assert(dsn, Not(Equals), "")
+
+	exporter := NewExporter(dsn, "")
+	c.Assert(exporter, NotNil)
+	// Assign the exporter to the suite
+	s.e = exporter
+
+	prometheus.MustRegister(exporter)
+}
+
+// TODO: it would be nice if cu didn't mostly just recreate the scrape function
+func (s *IntegrationSuite) TestAllNamespacesReturnResults(c *C) {
+	// Setup a dummy channel to consume metrics
+	ch := make(chan prometheus.Metric, 100)
+	go func() {
+		for range ch {
+		}
+	}()
+
+	// Open a database connection
+	db, err := sql.Open("postgres", s.e.dsn)
+	c.Assert(db, NotNil)
+	c.Assert(err, IsNil)
+	defer db.Close()
+
+	// Do a version update
+	err = s.e.checkMapVersions(ch, db)
+	c.Assert(err, IsNil)
+
+	err = querySettings(ch, db)
+	if !c.Check(err, Equals, nil) {
+		fmt.Println("## ERRORS FOUND")
+		fmt.Println(err)
+	}
+
+	// This should never happen in our test cases.
+	errMap := queryNamespaceMappings(ch, db, s.e.metricMap, s.e.queryOverrides)
+	if !c.Check(len(errMap), Equals, 0) {
+		fmt.Println("## NAMESPACE ERRORS FOUND")
+		for namespace, err := range errMap {
+			fmt.Println(namespace, ":", err)
+		}
+	}
+}
+
+// TestInvalidDsnDoesntCrash tests that specifying an invalid DSN doesn't crash
+// the exporter. Related to https://github.com/wrouesnel/postgres_exporter/issues/93
+// although not a replication of the scenario.
+func (s *IntegrationSuite) TestInvalidDsnDoesntCrash(c *C) {
+	queriesPath := os.Getenv("PG_EXPORTER_EXTEND_QUERY_PATH")
+
+	// Setup a dummy channel to consume metrics
+	ch := make(chan prometheus.Metric, 100)
+	go func() {
+		for range ch {
+		}
+	}()
+
+	// Send a bad DSN
+	exporter := NewExporter("invalid dsn", queriesPath)
+	c.Assert(exporter, NotNil)
+	exporter.scrape(ch)
+
+	// Send a DSN to a non-listening port.
+	exporter = NewExporter("postgresql://nothing:nothing@127.0.0.1:1/nothing", queriesPath)
+	c.Assert(exporter, NotNil)
+	exporter.scrape(ch)
+}
+
+// TestUnknownMetricParsingDoesntCrash deliberately deletes all the column maps out
+// of an exporter to test that the default metric handling code can cope with unknown columns.
+func (s *IntegrationSuite) TestUnknownMetricParsingDoesntCrash(c *C) {
+	// Setup a dummy channel to consume metrics
+	ch := make(chan prometheus.Metric, 100)
+	go func() {
+		for range ch {
+		}
+	}()
+
+	dsn := os.Getenv("DATA_SOURCE_NAME")
+	c.Assert(dsn, Not(Equals), "")
+
+	exporter := NewExporter(dsn, "")
+	c.Assert(exporter, NotNil)
+
+	// Convert the default maps into a list of empty maps.
+	emptyMaps := make(map[string]map[string]ColumnMapping, 0)
+	for k := range exporter.builtinMetricMaps {
+		emptyMaps[k] = map[string]ColumnMapping{}
+	}
+	exporter.builtinMetricMaps = emptyMaps
+
+	// scrape the exporter and make sure it works
+	exporter.scrape(ch)
+}