Hello Crate¶

To get started let’s have a quick look on how Crate Data can be accessed via the bare HTTP-Endpoints. This tutorial uses the Curl command-line utility to do the requests.

To check if Crate Data is running, we can do a GET on the root, which displays basic system information:

sh$ curl -sS '127.0.0.1:4200/?pretty=1'
{
  "ok" : true,
  "status" : 200,
  "name" : "crate",
  "version" : {
    "number" : "...",
    "build_hash" : "...",
    "build_timestamp" : "...",
    "build_snapshot" : ...,
    "es_version" : "...",
    "lucene_version" : "..."
  }
}

Note

The pretty query parameter used above tells Crate Data to pretty print results. This works for every endpoint.

In this guide we want to create a database for quotes. Let’s create the index and the quote type, which will contain information about the author of the quote and the quote itself:

sh$ curl -sSX POST 'http://127.0.0.1:4200/_sql?pretty=1&refresh=true' -d @- <<EOF
... {
... "stmt": "create table quotes (author string, content string)"
... }
... EOF
{
  "cols" : [ ],
  "rows" : [ ],
  "rowcount" : 1,
  "duration" : ...
}

Now we can add the first quote to the database:

sh$ curl -sSX POST '127.0.0.1:4200/_sql?pretty=1&refresh=true' -d @- <<EOF
... {
... "stmt": "insert into quotes values('Me', 'Hello Crate!')"
... }
... EOF
{
  "cols" : [ ],
  "rows" : [ ],
  "rowcount" : 1,
  "duration" : ...
}

Refresh in order to make the result immediately visible in subsequent queries:

sh$ curl -sSX POST '127.0.0.1:4200/quotes/_refresh?pretty=1'
{
  "_shards" : {
    "total" : 10,
    "successful" : 5,
    "failed" : 0
  }
}

We can now view what we have just inserted like this:

sh$ curl -sSX POST '127.0.0.1:4200/_sql?pretty=1' -d @- <<EOF
... {
... "stmt": "select author, content from quotes order by author"
... }
... EOF
{
  "cols" : [ "author", "content" ],
  "rows" : [ [ "Me", "Hello Crate!" ] ],
  "rowcount" : 1,
  "duration" : ...
}

Let’s add another quote:

sh$ curl -sSX POST '127.0.0.1:4200/_sql?pretty=1&refresh=true' -d @- <<EOF
... {
... "stmt": "insert into quotes values('Ford', 'Don''t panic... don''t panic...')"
... }
... EOF
{
  "cols" : [ ],
  "rows" : [ ],
  "rowcount" : 1,
  "duration" : ...
}

Refresh again:

sh$ curl -sSX POST '127.0.0.1:4200/quotes/_refresh?pretty=1'
{
  "_shards" : {
    "total" : 10,
    "successful" : 5,
    "failed" : 0
  }
}

Looking up only Ford’s quotes:

sh$ curl -sSX POST '127.0.0.1:4200/_sql?pretty=1' -d @- <<EOF
... {
... "stmt": "select content from quotes where author='Ford'"
... }
... EOF
{
  "cols" : [ "content" ],
  "rows" : [ [ "Don't panic... don't panic..." ] ],
  "rowcount" : 1,
  "duration" : ...
}