feat(elasticsearch): support @elastic/elasticsearch client

BREAKING: Support new elasticsearch configuration format.

As part of updating to elasticsearch 8, I'm updating pelias from the
deprecated `elastic` package to it's successor `@elastic/elasticsearch`
which supports both es7 and 8 (and some older versions too, but I think we
only care about 7+).

Note that this is a backwards incompatible change - old pelias code
using the `elasticsearch` package will not be able to use these new
configs.

apiVersion is determined by the client version, so it's no longer
necessary.

`keepAlive` is true by default, you need to set `agent: false` to
disable it:

    const client = new Client({
      node: 'http://localhost:9200',
      // Disable agent and keep-alive
      agent: false
    })

`hosts` is now `nodes` (or `node`) and has a different format.

Deleted parameters that aren't used in the new client:

 - `env`: I'm not sure what it's for. I suspect it's a pelias thing, not
   an elasticsearch thing, which seems like a conflation of the
   responsibilities of 'esclient config' vs 'pelias env mgmt'. Maybe I'm
   confused though.

 - `log`: The new elasticsearch client emits events instead of logging.

config/defaults.json

@@ -1,19 +1,7 @@
 {
   "esclient": {
-    "apiVersion": "7.x",
-    "keepAlive": true,
     "requestTimeout": "120000",
-    "hosts": [{
-      "env": "development",
-      "protocol": "http",
-      "host": "localhost",
-      "port": 9200
-    }],
-    "log": [{
-      "type": "stdio",
-      "json": false,
-      "level": [ "error", "warning" ]
-    }]
+    "nodes": ["http://localhost:9200"]
   },
   "elasticsearch": {
     "settings": {

config/env.json

@@ -1,19 +1,6 @@
 {
   "esclient": {
-    "hosts": [
-      {
-        "env": "production",
-        "protocol": "http",
-        "host": "localhost",
-        "port": 9200
-      },
-      {
-        "env": "production",
-        "protocol": "http",
-        "host": "localhost",
-        "port": 9300
-      }
-    ]
+    "nodes": ["http://localhost:9200", "http://localhost:9300"]
   },
   "imports": {
     "geonames": {

test/expected-deep.json

@@ -1,24 +1,7 @@
 {
   "esclient": {
-    "apiVersion": "7.x",
-    "keepAlive": true,
     "requestTimeout": "120000",
-    "hosts": [{
-       "env": "production",
-       "protocol": "http",
-       "host": "localhost",
-       "port": 9200
-     },{
-       "env": "production",
-       "protocol": "http",
-       "host": "localhost",
-       "port": 9300
-    }],
-    "log": [{
-      "type": "stdio",
-      "json": false,
-      "level": [ "error", "warning" ]
-    }]
+    "nodes": ["http://localhost:9200", "http://localhost:9300"]
   },
   "elasticsearch": {
     "settings": {

test/generate.js

@@ -16,8 +16,8 @@ module.exports.generate.development = function(test) {
     t.equal(typeof config, 'object', 'valid function');
     t.deepEqual(c, defaults, 'defaults');
     t.equal(typeof c.esclient, 'object', 'valid property');
-    t.equal(Object.keys(c.esclient).length, 5, 'copied all default properties');
-    t.equal(c.esclient.hosts.length, 1, 'defaults');
+    t.equal(Object.keys(c.esclient).length, 2, 'copied all default properties');
+    t.equal(c.esclient.nodes.length, 1, 'defaults');
     t.end();
 
     // reset localpath
@@ -37,7 +37,7 @@ module.exports.generate.production = function(test) {
     t.notDeepEqual(c, defaults, 'valid function');
     t.equal(typeof c.esclient, 'object', 'valid property');
     t.equal(Object.keys(c.esclient).length, 1, 'deleted all default properties');
-    t.equal(c.esclient.hosts.length, 2, 'shallow merge');
+    t.equal(c.esclient.nodes.length, 2, 'shallow merge');
     t.end();
 
     // unset the PELIAS_CONFIG env var
@@ -52,8 +52,8 @@ module.exports.generate.production = function(test) {
     t.equal(typeof config, 'object', 'valid function');
     t.notDeepEqual(c, defaults, 'valid function');
     t.equal(typeof c.esclient, 'object', 'valid property');
-    t.equal(Object.keys(c.esclient).length, 5, 'keep all default properties');
-    t.equal(c.esclient.hosts.length, 2, 'deep merge should set two hosts');
+    t.equal(Object.keys(c.esclient).length, 2, 'keep all default properties');
+    t.equal(c.esclient.nodes.length, 2, 'deep merge should set two nodes');
     t.end();
 
     // unset the PELIAS_CONFIG env var
@@ -68,8 +68,8 @@ module.exports.generate.production = function(test) {
     t.equal(typeof config, 'object', 'valid function');
     t.notDeepEqual(c, defaults, 'valid function');
     t.equal(typeof c.esclient, 'object', 'valid property');
-    t.equal(Object.keys(c.esclient).length, 5, 'keep all default properties');
-    t.equal(c.esclient.hosts.length, 2, 'deep merge should set two hosts');
+    t.equal(Object.keys(c.esclient).length, 2, 'keep all default properties');
+    t.equal(c.esclient.nodes.length, 2, 'deep merge should set two nodes');
     t.end();
 
     // unset the PELIAS_CONFIG env var
@@ -103,7 +103,7 @@ module.exports.generate.local = function(test) {
     t.equal(typeof config, 'object', 'valid function');
     t.notDeepEqual(c, defaults, 'valid function');
     t.equal(typeof c.esclient, 'object', 'valid property');
-    t.equal(Object.keys(c.esclient).length, 5, 'keep all default properties');
+    t.equal(Object.keys(c.esclient).length, 2, 'keep all default properties');
     t.equal(c.interpolation.client.adapter, 'http', 'interpolation client');
     t.equal(c.interpolation.client.host, 'http://localhost:9999', 'interpolation client');
     t.equal(c.imports.geonames.datapath, '/media/hdd', 'local paths');