custom formatters (metrico#217)

* protobuf ingestion test

* debug

* fix test node14

* remove logs

Co-authored-by: Lorenzo Mangani <[email protected]>

Author: akvlad

lib/handlers/common.js

@@ -0,0 +1,59 @@
+const eng = require('../../plugins/engine')
+const { parseCliQL } = require('../cliql')
+const { Transform } = require('stream')
+const { scanClickhouse, scanFingerprints } = require('../db/clickhouse')
+
+module.exports.checkCustomPlugins = async (options) => {
+  options.API = options.API || {
+    logql: async (query, start, end, limit) => {
+      const params = {
+        query,
+        start,
+        end,
+        limit,
+        direction: 'backward',
+        step: '60s'
+      }
+      const req = {
+        query: params
+      }
+      const res = new Transform({
+        transform (chunk, encoding, callback) {
+          callback(null, chunk)
+        }
+      })
+      res.writeHead = () => {}
+      const cliqlParams = parseCliQL(req.query.query)
+      if (cliqlParams) {
+        scanClickhouse(cliqlParams, { res }, params)
+      } else {
+        await scanFingerprints(
+          req.query,
+          { res: res }
+        )
+      }
+      let str = ''
+      res.on('data', (d) => {
+        str += d
+      })
+      await new Promise((resolve, reject) => {
+        res.once('error', reject)
+        res.once('close', resolve)
+        res.once('end', resolve)
+      })
+      return JSON.parse(str)
+    }/* ,
+    promql: async () => {
+
+    } */
+  }
+  const plugins = eng.getPlg({ type: 'custom_processor' })
+  for (const plugin of Object.values(plugins)) {
+    for (const e of Object.entries(options)) {
+      plugin[e[0]] = e[1]
+    }
+    if (plugin.check()) {
+      return await plugin.process()
+    }
+  }
+}

lib/handlers/query_range.js

@@ -10,6 +10,7 @@
 */
 
 const { parseCliQL } = require('../cliql')
+const { checkCustomPlugins } = require('./common')
 
 async function handler (req, res) {
   req.log.debug('GET /loki/api/v1/query_range')
@@ -28,17 +29,22 @@ async function handler (req, res) {
   const cliqlParams = parseCliQL(req.query.query)
   if (cliqlParams) {
     this.scanClickhouse(cliqlParams, res, params)
-  } else {
-    try {
-      await this.scanFingerprints(
-        req.query,
-        { res: res.raw }
-      )
-      res.hijack()
-    } catch (err) {
-      req.log.error({ err })
-      res.send(resp)
-    }
+    return
+  }
+  const pluginOut = await checkCustomPlugins(req.query)
+  if (pluginOut) {
+    res.header('Content-Type', pluginOut.type)
+    return res.send(pluginOut.out)
+  }
+  try {
+    await this.scanFingerprints(
+      req.query,
+      { res: res.raw }
+    )
+    res.hijack()
+  } catch (err) {
+    req.log.error({ err })
+    res.send(resp)
   }
 }
 

plugins/base/custom_processor/index.js

@@ -0,0 +1,11 @@
+const { PluginTypeLoaderBase } = require('plugnplay')
+module.exports = class extends PluginTypeLoaderBase {
+  exportSync (opts) {
+    return {
+      props: ['check', 'process'],
+      validate: (exports) => {
+        return exports
+      }
+    }
+  }
+}

plugins/base/custom_processor/plugnplay.yml

@@ -0,0 +1,4 @@
+id: custom_processor
+name: Custom Processor Plugin
+description: plugin to custom process a logql / promql request
+loader: index.js

plugins/output_format/index.js

@@ -0,0 +1,54 @@
+const { PluginLoaderBase } = require('plugnplay')
+
+/**
+ * @class Plugin
+ * @property {string} query
+ * @property start {number} start in NS
+ * @property end {string} end in NS
+ * @property type {string} promql or logql
+ * @property limit {number}
+ * @property {{
+ *   logql: (query: string, startNS: number, endNS: number, limit: number) => Promise<Object>
+ * }} API
+ *   promql: (query: string, startNS: number, endNS: number, limit: number) => Promise<Object> //not implemented
+ */
+class Plugin {
+  /**
+   * @method
+   * @name check
+   * @this {Plg}
+   * @returns {boolean} if this plugin is usable for the query
+   */
+  check () {
+    return this.query.match(/^toCsv\(.+\)\s*$/)
+  }
+
+  /**
+   * @method
+   * @name process
+   * @this {Plg}
+   * @returns {Promise<{type: string, out: string}>} The raw output
+   */
+  async process () {
+    const match = this.query.match(/^toCsv\((.+)\)$/)
+    const response = await this.API.logql(match[1], this.start, this.end, this.limit)
+    let res = ''
+    for (const stream of response.data.result) {
+      const labels = JSON.stringify(stream.stream)
+      for (const val of stream.values) {
+        res += `${labels}\t${val[0]}\t${val[1]}\n`
+      }
+    }
+    return {
+      type: 'text/csv',
+      out: res
+    }
+  }
+}
+class Plg extends PluginLoaderBase {
+  exportSync (api) {
+    return new Plugin()
+  }
+}
+
+module.exports = Plg

plugins/output_format/plugnplay.yml

@@ -0,0 +1,5 @@
+id: output_format
+name: Format Output
+description: Change output format
+loader: index.js
+type: custom_processor