Add support for tailing Kubernetes pod logs

This introduces support for reading logs via the Kubernetes API server
using the `kubectl logs` utility.

config/config.go

@@ -108,6 +108,9 @@ type ServerConfig struct {
 	AivenProjectID string `ini:"aiven_project_id"`
 	AivenServiceID string `ini:"aiven_service_id"`
 
+	K8sKubeConfigPath string `ini:"k8s_kubeconfig_path"`
+	K8sApiServerUrl   string `ini:"k8s_api_server_url"`
+
 	SectionName string
 	Identifier  ServerIdentifier
 
@@ -133,6 +136,13 @@ type ServerConfig struct {
 	// on the specifed "hostname:port" for Postgres log messages
 	LogSyslogServer string `ini:"db_log_syslog_server"`
 
+	// Configure the collector to tail a container within a Kubernetes pod
+	LogKubernetesPod string `ini:"db_log_kubernetes_pod"`
+	// The container name within the kubernetes pod to tail
+	LogKubernetesContainer string `ini:"db_log_kubernetes_container"`
+	// The namespace of the pod to tail, if not set will be "default"
+	LogKubernetesNamespace string `ini:"db_log_kubernetes_namespace"`
+
 	// Configures the collector to use the "pg_read_file" (superuser) or
 	// "pganalyze.read_log_file" (helper) function to retrieve log data
 	// directly over the Postgres connection. This only works when superuser

config/read.go

@@ -216,6 +216,12 @@ func getDefaultConfig() *ServerConfig {
 	if logSyslogServer := os.Getenv("LOG_SYSLOG_SERVER"); logSyslogServer != "" {
 		config.LogSyslogServer = logSyslogServer
 	}
+	if logKubernetesPodName := os.Getenv("LOG_KUBERNETES_POD"); logKubernetesPodName != "" {
+		config.LogKubernetesPod = logKubernetesPodName
+	}
+	if logKubernetesContainerName := os.Getenv("LOG_KUBERNETES_CONTAINER"); logKubernetesContainerName != "" {
+		config.LogKubernetesContainer = logKubernetesContainerName
+	}
 	if alwaysCollectSystemData := os.Getenv("PGA_ALWAYS_COLLECT_SYSTEM_DATA"); alwaysCollectSystemData != "" {
 		config.AlwaysCollectSystemData = parseConfigBool(alwaysCollectSystemData)
 	}

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/go-ini/ini v1.62.0
 	github.com/go-ole/go-ole v0.0.0-20160708033836-be49f7c07711 // indirect
 	github.com/golang-jwt/jwt/v4 v4.1.0 // indirect
-	github.com/golang/protobuf v1.4.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/gopherjs/gopherjs v0.0.0-20181103185306-d547d1d9531e // indirect
 	github.com/gorhill/cronexpr v0.0.0-20160318121724-f0984319b442
 	github.com/guregu/null v0.0.0-20160228005316-41961cea0328
@@ -30,7 +30,6 @@ require (
 	github.com/jtolds/gls v4.2.0+incompatible // indirect
 	github.com/juju/syslog v0.0.0-20150205155936-6be94e8b7187
 	github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515
-	github.com/kr/pretty v0.2.1 // indirect
 	github.com/kylelemons/godebug v0.0.0-20170224010052-a616ab194758
 	github.com/lib/pq v1.10.7
 	github.com/mitchellh/mapstructure v1.4.2 // indirect
@@ -44,14 +43,16 @@ require (
 	golang.org/x/crypto v0.6.0 // indirect
 	golang.org/x/net v0.7.0
 	google.golang.org/api v0.32.0
-	google.golang.org/protobuf v1.25.0
+	google.golang.org/protobuf v1.28.1
 	gopkg.in/ini.v1 v1.62.0 // indirect
 	gopkg.in/mcuadros/go-syslog.v2 v2.3.0
 )
 
 require (
 	github.com/pganalyze/pg_query_go/v4 v4.2.0
 	github.com/prometheus/procfs v0.7.3
+	k8s.io/api v0.26.2
+	k8s.io/client-go v0.26.2
 )
 
 require (
@@ -62,31 +63,59 @@ require (
 	github.com/Azure/go-autorest/autorest/validation v0.3.1 // indirect
 	github.com/Azure/go-autorest/logger v0.2.1 // indirect
 	github.com/Azure/go-autorest/tracing v0.6.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/devigned/tab v0.1.1 // indirect
-	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
-	github.com/google/go-cmp v0.5.4 // indirect
+	github.com/emicklei/go-restful/v3 v3.9.0 // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.20.0 // indirect
+	github.com/go-openapi/swag v0.19.14 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/google/gnostic v0.5.7-v3refs // indirect
+	github.com/google/go-cmp v0.5.9 // indirect
+	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/googleapis/gax-go/v2 v2.0.5 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.1 // indirect
+	github.com/imdario/mergo v0.3.6 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/jstemmer/go-junit-report v0.9.1 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
+	github.com/mailru/easyjson v0.7.6 // indirect
 	github.com/mattn/go-colorable v0.1.2 // indirect
 	github.com/mattn/go-isatty v0.0.8 // indirect
 	github.com/mgutz/ansi v0.0.0-20170206155736-9520e82c474b // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/tklauser/go-sysconf v0.3.9 // indirect
 	github.com/tklauser/numcpus v0.3.0 // indirect
 	go.opencensus.io v0.22.4 // indirect
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect
 	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
-	golang.org/x/oauth2 v0.0.0-20200902213428-5d25da1a8d43 // indirect
+	golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b // indirect
 	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4 // indirect
 	golang.org/x/sys v0.5.0 // indirect
 	golang.org/x/term v0.5.0 // indirect
 	golang.org/x/text v0.7.0 // indirect
+	golang.org/x/time v0.0.0-20220210224613-90d013bbcef8 // indirect
 	golang.org/x/tools v0.1.12 // indirect
-	google.golang.org/appengine v1.6.6 // indirect
-	google.golang.org/genproto v0.0.0-20201002142447-3860012362da // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/genproto v0.0.0-20201019141844-1ed22bb0c154 // indirect
 	google.golang.org/grpc v1.32.0 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/apimachinery v0.26.2 // indirect
+	k8s.io/klog/v2 v2.80.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20221012153701-172d655c2280 // indirect
+	k8s.io/utils v0.0.0-20221107191617-1a15be271d1d // indirect
+	sigs.k8s.io/json v0.0.0-20220713155537-f223a00ba0e2 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
+	sigs.k8s.io/yaml v1.3.0 // indirect
 )
 
 go 1.19