Add hostname and service labels (#12)

* Add hostname and service labels

* Update prometheus example config

* No logs

index.js

@@ -93,7 +93,7 @@ class PrometheusDhtBridge extends ReadyResource {
     if (this.opened) await this._writeAliases()
   }
 
-  putAlias (alias, targetPubKey, { write = true } = {}) {
+  putAlias (alias, targetPubKey, hostname, service, { write = true } = {}) {
     if (!this.opened && write) throw new Error('Cannot put aliases before ready')
 
     targetPubKey = idEnc.decode(idEnc.normalize(targetPubKey))
@@ -111,10 +111,13 @@ class PrometheusDhtBridge extends ReadyResource {
 
     const entry = new AliasesEntry(
       new ScraperClient(this.swarm, targetPubKey),
+      hostname,
+      service,
       Date.now() + this.entryExpiryMs
     )
 
     this.aliases.set(alias, entry)
+    // TODO: just emit entry?
     this.emit('set-alias', { alias, publicKey: targetPubKey, scrapeClient: entry.scrapeClient })
     const updated = true
 
@@ -192,11 +195,12 @@ class PrometheusDhtBridge extends ReadyResource {
   async _loadAliases () { // should never throw
     try {
       const aliases = await readPromTargets(this.promTargetsLoc)
-      for (const [alias, pubKey] of aliases) {
+
+      for (const [alias, { z32PubKey, hostname, service }] of aliases) {
         // Write false since we load an existing state
         // (otherwise we overwrite them 1 by 1, and can lose
         // entries if we restart/crash during setup)
-        this.putAlias(alias, pubKey, { write: false })
+        this.putAlias(alias, z32PubKey, hostname, service, { write: false })
       }
     } catch (e) {
       this.emit('load-aliases-error', e)
@@ -205,10 +209,12 @@ class PrometheusDhtBridge extends ReadyResource {
 }
 
 class AliasesEntry extends ReadyResource {
-  constructor (scrapeClient, expiry) {
+  constructor (scrapeClient, hostname, service, expiry) {
     super()
 
     this.scrapeClient = scrapeClient
+    this.hostname = hostname
+    this.service = service
     this.expiry = expiry
   }
 

lib/prom-targets.js

@@ -9,7 +9,9 @@ async function writePromTargets (location, aliases) {
   // than to extract the pubkey in the caller
   for (const [target, entry] of aliases) {
     const pubKey = idEnc.normalize(entry.targetKey)
-    targets.push(`${target}:${pubKey}`)
+    const hostname = entry.hostname.replaceAll(':', '-')
+    const service = entry.service.replaceAll(':', '-')
+    targets.push(`${target}:${pubKey}:${hostname}:${service}`)
   }
 
   const content = [
@@ -38,8 +40,8 @@ async function readPromTargets (location) {
 
   const aliases = new Map()
   for (const target of fullJson[0].targets) {
-    const [alias, z32PubKey] = target.split(':')
-    aliases.set(alias, z32PubKey)
+    const [alias, z32PubKey, hostname, service] = target.split(':')
+    aliases.set(alias, { z32PubKey, hostname, service })
   }
 
   return aliases

package.json

@@ -41,8 +41,8 @@
   "dependencies": {
     "b4a": "^1.6.6",
     "debounceify": "^1.1.0",
-    "dht-prom-alias-rpc": "^0.0.1-alpha.0",
-    "dht-prom-client": "^0.0.1-alpha.9",
+    "dht-prom-alias-rpc": "^0.0.1-alpha.1",
+    "dht-prom-client": "^0.0.1-alpha.10",
     "fastify": "^4.28.0",
     "graceful-goodbye": "^1.3.0",
     "hypercore-id-encoding": "^1.3.0",

prometheus/prometheus.yml

@@ -1,8 +1,8 @@
 # This is an example config.
 
 global:
-  scrape_interval:     5s
-  evaluation_interval: 5s
+  scrape_interval: 1s
+  evaluation_interval: 1s
 
 # Source for relabeling approach: https://stackoverflow.com/questions/59866342/prometheus-dynamic-metrics-path
 scrape_configs:
@@ -12,9 +12,17 @@ scrape_configs:
     - 'targets.json'
   relabel_configs:
     - source_labels: [__address__]
-      regex: "(.+):.{52}" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
+      regex: "(.+):.{52}:.+" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
       replacement: "/scrape/$1/metrics" # Captured part + /metrics appendix
       target_label: __metrics_path__ # => instead of default /metrics
     - source_labels: [__address__]
       replacement: "localhost:30000" # Replace with the port where the dht-prometheus http server runs
       target_label: __address__
+    - source_labels: [__address__]
+      regex: ".+:.{52}:([^:]+):.+:" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
+      replacement: "$1" # Captured part + /metrics appendix
+      target_label: hostname
+    - source_labels: [__address__]
+      regex: ".+:.{52}:[^:]+:(.+):" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
+      replacement: "$1" # Captured part + /metrics appendix
+      target_label: service

test/integration.js

@@ -323,7 +323,8 @@ function getClient (t, bootstrap, scraperPubKey, sharedSecret, { name = 'dummy'
     idEnc.decode(scraperPubKey),
     name,
     sharedSecret,
-    { bootstrap }
+    'my-service',
+    { bootstrap, hostname: 'my-hostname' }
   )
 
   t.teardown(async () => {
@@ -349,12 +350,20 @@ scrape_configs:
     - '${promTargetsLoc}'
   relabel_configs:
     - source_labels: [__address__]
-      regex: "(.+):.{52}" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the key
+      regex: "(.+):.{52}:.+" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
       replacement: "/scrape/$1/metrics" # Captured part + /metrics appendix
       target_label: __metrics_path__ # => instead of default /metrics
     - source_labels: [__address__]
-      replacement: "${bridgeHttpAddress}"
-      target_label: __address__       # => That's the actual address
+      replacement: "${bridgeHttpAddress}" # Replace with the port where the dht-prometheus http server runs
+      target_label: __address__
+    - source_labels: [__address__]
+      regex: ".+:.{52}:([^:]+):.+:" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
+      replacement: "$1" # Captured part + /metrics appendix
+      target_label: hostname
+    - source_labels: [__address__]
+      regex: ".+:.{52}:[^:]+:(.+):" # Targets are structured as <targetname>:<target z32 key>, and at prometheus level we only need the target name
+      replacement: "$1" # Captured part + /metrics appendix
+      target_label: service
 `
 
   await fs.promises.writeFile(loc, content)

test/test.js

@@ -256,7 +256,8 @@ async function setup (t, bridgeOpts = {}) {
     scraperPubKey,
     'dummy',
     sharedSecret,
-    { bootstrap }
+    'my-service',
+    { bootstrap, hostname: 'my-hostname' }
   )
 
   t.teardown(async () => {