Revert "app/vlselect: introduce -vmalert.proxyURL flag to proxy /select/vmalert requests to VMAlert (#5)"

This reverts commit 2d4b343.

Reason for revert: this commit mixes two unrelated features:

- Proxying vmalert requests ( #90 )
- Introducing vmui config handler at /select/vmui/config.json ( there should be a separate feature request with the explanation why this handler is needed )
- Returning AccountID and ProjectID response headers ( #656 )

It is better from the maintenance and git history investigation PoV to split the implementation of these features into separate pull requests.

This commit also has a few issues in the code, which must be addressed in the follow-up pull requests:

- The description of the `-vmalert.proxyURL` command-line flag misses a whitespace between the `vmalert.` and `See`.
- The description of the `-vmalert.proxyURL` command-line flag contains non-canonical link to docs - https://docs.victoriametrics.com/victorialogs#vmalert .
  It must be https://docs.victoriametrics.com/victorialogs/#vmalert
- The `r.URL.Path = strings.TrimPrefix(path, "/select")` line isn't needed in the code block, which returns vmui config to the client.

Updates #5

Author: valyala

app/vlselect/main.go

@@ -3,16 +3,12 @@ package vlselect
 import (
 	"context"
 	"embed"
-	"encoding/json"
 	"flag"
 	"fmt"
 	"net/http"
-	nethttputil "net/http/httputil"
-	"net/url"
 	"strings"
 	"time"
 
-	"github.com/VictoriaMetrics/VictoriaMetrics/lib/buildinfo"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httputil"
@@ -33,9 +29,6 @@ var (
 
 	disableSelect   = flag.Bool("select.disable", false, "Whether to disable /select/* HTTP endpoints")
 	disableInternal = flag.Bool("internalselect.disable", false, "Whether to disable /internal/select/* HTTP endpoints")
-
-	vmalertProxyURL = flag.String("vmalert.proxyURL", "", "Optional URL for proxying requests to vmalert."+
-		"See https://docs.victoriametrics.com/victorialogs#vmalert.")
 )
 
 func getDefaultMaxConcurrentRequests() int {
@@ -55,8 +48,6 @@ func getDefaultMaxConcurrentRequests() int {
 // Init initializes vlselect
 func Init() {
 	concurrencyLimitCh = make(chan struct{}, *maxConcurrentRequests)
-	initVMUIConfig()
-	initVMAlertProxy()
 
 	internalselect.Init()
 }
@@ -125,22 +116,6 @@ func selectHandler(w http.ResponseWriter, r *http.Request, path string) bool {
 		return true
 	}
 	if strings.HasPrefix(path, "/select/vmui/") {
-		if path == "/select/vmui/config.json" {
-			w.Header().Set("Content-Type", "application/json")
-			r.URL.Path = strings.TrimPrefix(path, "/select")
-			if disableTenantControls := r.Header.Get("VL-Disable-Tenant-Controls"); disableTenantControls == "true" {
-				w.Header().Set("VL-Disable-Tenant-Controls", "true")
-			} else {
-				if accountID := r.Header.Get("AccountID"); len(accountID) > 0 {
-					w.Header().Set("AccountID", accountID)
-				}
-				if projectID := r.Header.Get("ProjectID"); len(projectID) > 0 {
-					w.Header().Set("ProjectID", projectID)
-				}
-			}
-			fmt.Fprint(w, vmuiConfig)
-			return true
-		}
 		if strings.HasPrefix(path, "/select/vmui/static/") {
 			// Allow clients caching static contents for long period of time, since it shouldn't change over time.
 			// Path to static contents (such as js and css) must be changed whenever its contents is changed.
@@ -242,17 +217,6 @@ func decRequestConcurrency() {
 func processSelectRequest(ctx context.Context, w http.ResponseWriter, r *http.Request, path string) bool {
 	httpserver.EnableCORS(w, r)
 	startTime := time.Now()
-	if strings.HasPrefix(path, "/select/vmalert/") {
-		vmalertRequests.Inc()
-		if len(*vmalertProxyURL) == 0 {
-			w.Header().Set("Content-Type", "application/json")
-			w.WriteHeader(http.StatusBadRequest)
-			fmt.Fprintf(w, "%s", `{"status":"error","msg":"for accessing vmalert flag '-vmalert.proxyURL' must be configured"}`)
-			return true
-		}
-		proxyVMAlertRequests(w, r)
-		return true
-	}
 	switch path {
 	case "/select/logsql/facets":
 		logsqlFacetsRequests.Inc()
@@ -327,72 +291,6 @@ func getMaxQueryDuration(r *http.Request) time.Duration {
 	return d
 }
 
-func proxyVMAlertRequests(w http.ResponseWriter, r *http.Request) {
-	defer func() {
-		err := recover()
-		if err == nil || err == http.ErrAbortHandler {
-			// Suppress http.ErrAbortHandler panic.
-			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1353
-			return
-		}
-		// Forward other panics to the caller.
-		panic(err)
-	}()
-	r.URL.Path = strings.TrimPrefix(r.URL.Path, "/select")
-	r.Host = vmalertProxyHost
-	vmalertProxy.ServeHTTP(w, r)
-}
-
-func initVMUIConfig() {
-	var cfg struct {
-		Version string `json:"version"`
-		License struct {
-			Type string `json:"type"`
-		} `json:"license"`
-		VMAlert struct {
-			Enabled bool `json:"enabled"`
-		} `json:"vmalert"`
-	}
-	cfg.Version = buildinfo.ShortVersion()
-	if cfg.Version == "" {
-		// buildinfo.ShortVersion() may return empty result for builds without tags
-		cfg.Version = buildinfo.Version
-	}
-	data, err := vmuiFiles.ReadFile("vmui/config.json")
-	if err != nil {
-		logger.Fatalf("cannot read vmui default config: %s", err)
-	}
-	err = json.Unmarshal(data, &cfg)
-	if err != nil {
-		logger.Fatalf("cannot parse vmui default config: %s", err)
-	}
-	cfg.VMAlert.Enabled = len(*vmalertProxyURL) != 0
-	data, err = json.Marshal(&cfg)
-	if err != nil {
-		logger.Fatalf("cannot create vmui config: %s", err)
-	}
-	vmuiConfig = string(data)
-}
-
-// initVMAlertProxy must be called after flag.Parse(), since it uses command-line flags.
-func initVMAlertProxy() {
-	if len(*vmalertProxyURL) == 0 {
-		return
-	}
-	proxyURL, err := url.Parse(*vmalertProxyURL)
-	if err != nil {
-		logger.Fatalf("cannot parse -vmalert.proxyURL=%q: %s", *vmalertProxyURL, err)
-	}
-	vmalertProxyHost = proxyURL.Host
-	vmalertProxy = nethttputil.NewSingleHostReverseProxy(proxyURL)
-}
-
-var (
-	vmalertProxyHost string
-	vmalertProxy     *nethttputil.ReverseProxy
-	vmuiConfig       string
-)
-
 var (
 	logsqlFacetsRequests = metrics.NewCounter(`vl_http_requests_total{path="/select/logsql/facets"}`)
 	logsqlFacetsDuration = metrics.NewSummary(`vl_http_request_duration_seconds{path="/select/logsql/facets"}`)
@@ -429,6 +327,4 @@ var (
 
 	// no need to track duration for tail requests, as they usually take long time
 	logsqlTailRequests = metrics.NewCounter(`vl_http_requests_total{path="/select/logsql/tail"}`)
-
-	vmalertRequests = metrics.NewCounter(`vl_http_requests_total{path="/select/vmalert"}`)
 )

docs/victorialogs/CHANGELOG.md

@@ -19,7 +19,6 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 ## tip
 
 * FEATURE: [querying](https://docs.victoriametrics.com/victorialogs/querying/): add an ability to return partial responses in [VictoriaLogs cluster setup](https://docs.victoriametrics.com/victorialogs/cluster/) when some of `vlstorage` nodes are unavailable. See [these docs](https://docs.victoriametrics.com/victorialogs/querying/#partial-responses) for details. See [#72](https://github.com/VictoriaMetrics/VictoriaLogs/issues/72).
-* FEATURE: proxy VMAlert requests at `/select/vmalert` path, when `-vmalert.proxyURL` flag is set. See [#90](https://github.com/VictoriaMetrics/VictoriaLogs/issues/90).
 * FEATURE: [vlselect](https://docs.victoriametrics.com/victorialogs/cluster/): add `-storageNode.usernameFile` command-line flag for dynamically reloading basic auth username for the corresponding `-storageNode` from the given file. See [#459](https://github.com/VictoriaMetrics/VictoriaLogs/issues/459).
 
 * BUGFIX: [LogsQL](https://docs.victoriametrics.com/victorialogs/logsql/): disallow incorrectly written filters such as `foo = bar`, `foo != bar`, `foo > bar`, etc. They must be written as `foo:=bar`, `foo:!=bar`, `foo:>bar`. See [#590](https://github.com/VictoriaMetrics/VictoriaLogs/issues/590).

docs/victorialogs/README.md

@@ -339,13 +339,6 @@ The following steps must be performed for restoring the partition data from back
 
 It is also possible to use **the disk snapshot** feature provided by the operating system or cloud provider in order to perform a backup.
 
-## vmalert
-
-VictoriaLogs is capable of proxying requests to [VMAlert](https://docs.victoriametrics.com/victorialogs/vmalert/)
-when `-vmalert.proxyURL` flag is set. Use this feature for accessing VMAlert API through VictoriaLogs Web interface.
-
-For accessing VMAlert API through VictoriaLogs configure `-vmalert.proxyURL` flag. All VMAlert endpoints become available at `http://<victorialogs-addr>:9428/select/vmalert`.
-
 ## Multitenancy
 
 VictoriaLogs supports multitenancy. A tenant is identified by `(AccountID, ProjectID)` pair, where `AccountID` and `ProjectID` are arbitrary 32-bit unsigned integers.

docs/victorialogs/vmalert.md

@@ -18,9 +18,6 @@ and [`/select/logsql/stats_query_range`](https://docs.victoriametrics.com/victor
 These endpoints return the log stats in a format compatible with [Prometheus querying API](https://prometheus.io/docs/prometheus/latest/querying/api/#instant-queries).
 It allows using VictoriaLogs as the datasource in vmalert, creating alerting and recording rules via [LogsQL](https://docs.victoriametrics.com/victorialogs/logsql/).
 
-Configure `-vmalert.proxyURL` on [VictoriaLogs](https://docs.victoriametrics.com/victorialogs/#vmalert){{% available_from "#" %}} to proxy requests to `vmalert`.
-Proxying is needed to access `vmalert`'s UI through [vmui](https://docs.victoriametrics.com/#vmui).
-
 > This page provides only integration instructions for vmalert and VictoriaLogs. See the full textbook for vmalert [here](https://docs.victoriametrics.com/victoriametrics/vmalert/).
 
 ## Quick Start