PSA


layout: true
class: animated fadeIn middle numbers

.footnote[
`PSA` - N. Dubray - ENSIIE - 2024 - [:book:](../index.html)
]

---

# MongoDB

.hcenter.w40[![](images/mongodb_logo.svg)]

## History
* **10gen software** started the development in **2007**
* Open source development model in **2009** (paid support and services)
* **10gen software** renamed to **MongoDB inc.** in **2013**
* October 2018, publicly-traded company (`MDB`)

## In an nutshell
* is a **NoSQL** database program (document database)
* can use schemas **or not**
* is **scalable** and **replicable** (with load-balancing)
* can execute javascript **server-side** (e.g. `mapreduce`)
* can do **transactions** (02/2018)
* one of the main databases for **Big Data**

.block[
* Repository: [https://github.com/mongodb/mongo](https://github.com/mongodb/mongo)
* Website: [https://www.mongodb.com](https://www.mongodb.com)
* License: `AGPLv3` + `Apache` license
]

---

# MongoDB - Characteristics

## Built-in capabilities

:+: Queries: field, range, regexp, javaScript (server-side)...  
:+: Indexing: **optional**, primary and secondary keys  
:+: Replication: **automatic election** of a new master in case of failure  
:+: Load balancing: **sharding** uses a **shard key** to distribute data over `MongoDB` instances  
:+: File storage: `MongoDB` can act as a **load-balanced**, **replicated** file system (`GridFS`)  
:+: Aggregation: allows to perform e.g. `mapreduce` operations  
:+: Capped collections: some collections can be capped and become **circular queues** when filled  
:+: Transactions: `ACID` since `v4.0`

---

# MongoDB - Scalability

:arrow_right: How to increase the performances of a given `DBMS` ?

.row[
.column.w65[
## Vertical scaling
:arrow_right: **Add resources to existing servers**  
:+: nothing to change in the servers config  
:warning: may cause some indisponibility  
:warning: is limited by the hardware  
]
.column.w30[
.mermaid[
  graph TD
  A(Master) --> B(Slave 0)
  A(Master) --> C(Slave 1)
  A(Master) --> D(Slave 2)
  style A fill:#2A2
  style B fill:#2A2
  style C fill:#2A2
  style D fill:#2A2
]
]
]

.row[
.column.w55[
## Horizontal scaling
:arrow_right: **Add more servers**  
:+: nothing to change in the servers config  
:+: can be transparent  
:+: is not limited by the hardware  
]
.column.w40[
.mermaid[
  graph TD
  A(Master) --> B(Slave 0)
  A(Master) --> C(Slave 1)
  A(Master) --> D(Slave 2)
  A(Master) -.-> E(Slave 3)
  style E fill:#2A2
]
]
]


## Horizontal scaling with `SQL`-type `DBMS`
:warning: is often done **manualy**  
:warning: **may break transactions integrity**

## Horizontal scaling with `MongoDB` (**sharding**)
:+: is a built-in mechanism  
:+: is almost transparent to the admin  
:+: can use different hardware  

---

# MongoDB - Schemas ?

## `SQL`-type `DBMS`
:warning: a schema has to be defined **before inserting data**  
:warning: **new data has to follow the existing schema**  
:warning: to change the schema, existing data must be **migrated**

.vspace[]

## `MongoDB`
:+: schemas can be used **or not**  
:+: if no schema is used, new data can have **any attributes**  
:+: a schema can be created, changed or removed at any time, **no migration needed**  
:arrow_right: a schema can be used for **updating** or **inserting** data

---

# MongoDB - Overview

## Data hierarchy
.mermaid[
  graph LR
  A(MongoDB instance) --> B
  B(Database) --> C
  C(Collection) --> D
  D(Document) --> E(Field)
]

## Example
.tree.hcenter[
`MongoDB` instance
* Database: `test_db`
   * Collection: `MusicRecords`
      * Document:
         * Field `"_id"`: `ObjectId("5b05cfb3c6256b28f54bf25e")`
         * Field `"band"`: `"Pink Floyd"`
         * Field `"song"`: `"Wish You Were Here"`
      * Document:
         * Field `"_id"`: `ObjectId("5b05cfb3c6256b28f54bf25f")`
         * Field `"band"`: `"Pink Floyd"`
         * Field `"song"`: `"Have a Cigar"`
         * Field `"year"`: `1975`
* Database: `other_db`

]

---

# MongoDB - Installation

## Ubuntu 17.10

```shell
*$ apt update
Hit:1 http://fr.archive.ubuntu.com/ubuntu artful InRelease
Hit:2 http://fr.archive.ubuntu.com/ubuntu artful-updates InRelease      
Hit:3 http://security.ubuntu.com/ubuntu artful-security InRelease       
Hit:4 http://fr.archive.ubuntu.com/ubuntu artful-backports InRelease
Reading package lists... Done                     
Building dependency tree       
Reading state information... Done
All packages are up to date.
*$ apt install mongodb-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libboost-chrono1.62.0 mongo-tools mongodb-clients
The following NEW packages will be installed:
  libboost-chrono1.62.0 mongo-tools mongodb-clients mongodb-server
0 upgraded, 4 newly installed, 0 to remove and 3 not upgraded.
Need to get 47.8 MB of archives.
After this operation, 207 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Get:1 http://fr.archive.ubuntu.com/ubuntu artful/main amd64 libboost-chrono1.62.0 amd64 1.62.0+dfsg-4build3 [11.8 kB]
Get:2 http://fr.archive.ubuntu.com/ubuntu artful/universe amd64 mongo-tools amd64 3.2.11-1 [9,993 kB]
Get:3 http://fr.archive.ubuntu.com/ubuntu artful/universe amd64 mongodb-clients amd64 1:3.4.7-1 [18.7 MB]
Get:4 http://fr.archive.ubuntu.com/ubuntu artful/universe amd64 mongodb-server amd64 1:3.4.7-1 [19.2 MB]
Fetched 47.8 MB in 20s (2,293 kB/s)                                                           
[...]
Setting up libboost-chrono1.62.0:amd64 (1.62.0+dfsg-4build3) ...
Setting up mongo-tools (3.2.11-1) ...
Setting up mongodb-clients (1:3.4.7-1) ...
Setting up mongodb-server (1:3.4.7-1) ...
Processing triggers for libc-bin (2.26-0ubuntu2.1) ...
```

---

# MongoDB - Installation

## Ubuntu >= 20.10

```shell
*$ wget -qO - https://www.mongodb.org/static/pgp/server-4.4.asc | sudo apt-key add -
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
OK
*$ echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.4.list
deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 multiverse
*$ sudo apt update
[...]
Get:18 https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4 Release.gpg [801 B]
Get:21 https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4/multiverse amd64 Packages [9 029 B]
Get:22 https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/4.4/multiverse arm64 Packages [6 951 B]
[...]
*$ sudo apt install -y mongodb-org
[...]
```

Follow [installation instructions](https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/#install-community-ubuntu-pkg).

---

# MongoDB - Configuration file

.row[
.column.w48[
:arrow_right: **Old format**

## .hcenter[\[/etc/mongodb.conf\]]
```ini
# mongodb.conf

# Where to store the data.
*dbpath=/home/mongodb

#where to log
*logpath=/home/mongodb/mongodb.log

logappend=true

bind_ip = 127.0.0.1
#port = 27017

# Enable journaling, http://www.mongodb.org/display/DOCS/Journaling
*journal=false

# Enables periodic logging of CPU utilization and I/O wait
#cpu = true

# Turn on/off security.  Off is currently the default
#noauth = true
#auth = true

[...]
```
]

.column.w48[
:arrow_right: **New format**

## .hcenter[\[/etc/mongodb.conf\]]
```ini
storage:
* dbPath: "/home/mongodb"
  journal:
*   enabled: false
systemLog:
  destination: file
* path: "/home/mongodb/mongodb.log"
  logAppend: true
net:
  bindIp: 127.0.0.1
  port: 27017
* maxIncomingConnections: 20000
security:
  authorization: disabled
```
]
]

---

# MongoDB - Start a server instance

:arrow_right: With `Systemd`, use `systemctl start unit.service`.

## .hcenter[\[Shell session\]]
```shell
*$ systemctl start mongodb.service
*$ systemctl status mongodb.service
● mongodb.service - An object/document-oriented database
   Loaded: loaded (/lib/systemd/system/mongodb.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2018-05-22 21:12:24 CEST; 55s ago
     Docs: man:mongod(1)
 Main PID: 748 (mongod)
    Tasks: 16 (limit: 4915)
   CGroup: /system.slice/mongodb.service
           └─748 /usr/bin/mongod --unixSocketPrefix=/run/mongodb --config /etc/mongodb.conf

May 22 21:12:24 dell-e5450 systemd[1]: Started An object/document-oriented database.
*$ journalctl -u mongodb
May 22 21:12:24 dell-e5450 systemd[1]: Started An object/document-oriented database.
```

---

# MongoDB - Insert some documents

:arrow_right: To use a database: `use dbName`  
:arrow_right: To create a collection: `db.createCollection('collectionName')`  
:arrow_right: To remove a collection: `db.dbName.drop()`  
:arrow_right: To insert a document: `db.dbName.insertOne(document)`  

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://127.0.0.1
MongoDB shell version v3.4.7
connecting to: mongodb://127.0.0.1
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.createCollection('MusicRecords')
{ "ok": 1 }
> db.createCollection('Movies')
{ "ok": 1 }
> db.Movies.drop()
true
> db.MusicRecords.insertOne({band:'Pink Floyd', song:'Wish You Were Here'})
{
        "acknowledged" : true,
        "insertedId" : ObjectId("5b05cfb3c6256b28f54bf25e")
}
> db.MusicRecords.insertOne({band:'Pink Floyd', song:'Have a Cigar', year: 1975})
{
        "acknowledged" : true,
        "insertedId" : ObjectId("5b05cfb3c6256b28f54bf25f")
}
```

---

# MongoDB - Retrieve some documents

:arrow_right: To retrieve one document: `db.dbName.findOne()`  
:arrow_right: To retrieve all documents: `db.dbName.find()`  
:arrow_right: To retrieve all documents matching a query: `db.dbName.find(query)`  

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://127.0.0.1
MongoDB shell version v3.4.7
connecting to: mongodb://127.0.0.1
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.MusicRecords.findOne()
{
        "_id" : ObjectId("5b05cfb3c6256b28f54bf25e"),
        "band" : "Pink Floyd",
        "song" : "Wish You Were Here"
}
> db.MusicRecords.find()
{ "_id" : ObjectId("5b05cfb3c6256b28f54bf25e"), "band" : "Pink Floyd", "song" : "Wish You Were Here" }
{ "_id" : ObjectId("5b05cfb3c6256b28f54bf25f"), "band" : "Pink Floyd", "song" : "Have a Cigar", "year" : 1975 }
> db.MusicRecords.find({year: 1975})
{ "_id" : ObjectId("5b05cfb3c6256b28f54bf25f"), "band" : "Pink Floyd", "song" : "Have a Cigar", "year" : 1975 }
```

---

# MongoDB - Users

## Database user
:arrow_right: Several users can be defined **for each database**  
:warning: Different users with the same name can exist for different databases  
:arrow_right: A user will have to be identified **for a given database**

.vspace[]

## User's roles
:arrow_right: User permitted actions are defined in **`roles`**  
:warning: Some roles can allow modifications **to other databases**  
:arrow_right: Several **built-in roles** exist, but **custom roles** can be constructed

.vspace[]

## Privileges
:arrow_right: A role is a set of **privileges**  
:arrow_right: Example of privileges for the `read` built-in role in database `test_db`:  
* `collStats`, `dbHash`, `dbStats`, `find`, `killCursors`, `listCollections`, `listIndexes`, `planCacheRead` for `test_db.*` collections.

---

# MongoDB - Built-in roles

.row[
.column.w48[
## Database User Roles
* `read`
* `readWrite`

## Database Administration Roles
* `dbAdmin`
* `dbOwner`
* `userAdmin`

## Cluster Administration Roles
* `clusterAdmin`
* `clusterManager`
* `clusterMonitor`
* `hostManager`
]

.column.w48[
## Backup and Restoration Roles
* `backup`
* `restore`

## :warning: All-Database Roles
* `readAnyDatabases`
* `readWriteAnyDatabase`
* `userAdminAnyDatabase`
* `dbAdminAnyDatabase`

## :warning: Superuser Roles
* `root`

## Internal Role
* `__system`: do not use :warning:
]
]

---

# MongoDB - Admin user

:warning: **Disable authorization** in the configuration file first !  

:arrow_right: Create a `root` user with `db.createUser()`.

## .hcenter[\[Shell session\]]
```shell
*$ mongo
> use admin
switched to db admin
> db.createUser({user:"toto", pwd: "toto123", roles: ["root"]})
Successfully added user: { "user" : "toto", "roles" : [ "root" ] }
```

---

# MongoDB - Database user

:arrow_right: Create a user with `readWrite` built-in role.

## .hcenter[\[Shell session\]]
```shell
*$ mongo
> use test_db
switched to db test_db
> db.createUser({user:"user0", pwd: "pwd0", roles: ["readWrite"]})
Successfully added user: { "user" : "user0", "roles" : [ "readWrite" ] }
```

---

# MongoDB - Configuration file with authorization

.row[
.column.w48[
:arrow_right: **Old format**

## .hcenter[\[/etc/mongodb.conf\]]
```ini
# mongodb.conf

# Where to store the data.
dbpath=/home/mongodb

#where to log
logpath=/home/mongodb/mongodb.log

logappend=true

bind_ip = 127.0.0.1
#port = 27017

# Enable journaling, http://www.mongodb.org/display/DOCS/Journaling
journal=false

# Enables periodic logging of CPU utilization and I/O wait
#cpu = true

# Turn on/off security.  Off is currently the default
#noauth = true
*auth = true

[...]
```
]

.column.w48[
:arrow_right: **New format**

## .hcenter[\[/etc/mongodb.conf\]]
```ini
storage:
  dbPath: "/home/mongodb"
  journal:
    enabled: false
systemLog:
  destination: file
  path: "/home/mongodb/mongodb.log"
  logAppend: true
net:
  bindIp: 127.0.0.1
  port: 27017
  maxIncomingConnections: 20000
security:
* authorization: enabled
```
]
]

---

# MongoDB - Restart a server instance

:arrow_right: With `Systemd`, use `systemctl restart unit.service`.

## .hcenter[\[Shell session\]]
```shell
*$ systemctl restart mongodb.service
*$ systemctl status mongodb.service
● mongodb.service - An object/document-oriented database
   Loaded: loaded (/lib/systemd/system/mongodb.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2018-05-22 23:21:40 CEST; 2s ago
     Docs: man:mongod(1)
 Main PID: 5868 (mongod)
    Tasks: 16 (limit: 4915)
   CGroup: /system.slice/mongodb.service
           └─5868 /usr/bin/mongod --unixSocketPrefix=/run/mongodb --config /etc/mongodb.conf

May 22 23:21:40 dell-e5450 systemd[1]: Started An object/document-oriented database.
*$ journalctl -u mongodb
May 22 21:12:24 dell-e5450 systemd[1]: Started An object/document-oriented database.
May 22 23:21:40 dell-e5450 systemd[1]: Stopping An object/document-oriented database...
May 22 23:21:40 dell-e5450 systemd[1]: Stopped An object/document-oriented database.
May 22 23:21:40 dell-e5450 systemd[1]: Started An object/document-oriented database.
```

---

# MongoDB - Login as admin

## Using CLI options

:arrow_right: Syntax: `mongo mongodb://user:passwd@host/db`

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://toto:toto123@127.0.0.1/admin
MongoDB server version: 3.4.7
> 
```

## Using `mongo` commands

:arrow_right: Command: `db.auth({user: 'user', pwd: 'pwd'})`

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://127.0.0.1
MongoDB shell version v3.4.7
connecting to: mongodb://127.0.0.1
MongoDB server version: 3.4.7
> use admin
switched to db admin
> db.auth({user:'toto', pwd:'WRONGPASSWORD'})
Error: Authentication failed.
0
> db.auth({user:'toto', pwd:'toto123'})
1
>
```

---

# MongoDB - Login as user

## Using CLI options

:arrow_right: Syntax: `mongo mongodb://user:passwd@host/db`

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
> 
```

## Using `mongo` commands

:arrow_right: Command: `db.auth({user: 'user', pwd: 'pwd'})`

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://127.0.0.1
MongoDB shell version v3.4.7
connecting to: mongodb://127.0.0.1
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.auth({user:'user0', pwd:'WRONGPASSWORD'})
Error: Authentication failed.
0
> db.auth({user:'user0', pwd:'pwd0'})
1
>
```

---

# MongoDB - Multiple authentications

:arrow_right: It is possible to authenticate as **different users at the same time**.

:arrow_right: Display connectionStatus with `db.runcommand({connectionStatus: 1})`.

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://toto:toto123@127.0.0.1/admin
MongoDB server version: 3.4.7
> db.runCommand({connectionStatus: 1})
{
        "authInfo" : {
                "authenticatedUsers" : [
                        {
*                               "user" : "toto",
                                "db" : "admin"
                        }
                ],
                "authenticatedUserRoles" : [
                        {
                                "role" : "root",
                                "db" : "admin"
                        }
                ]
        },
        "ok" : 1
}
```

---

# MongoDB - Multiple authentications

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://toto:toto123@127.0.0.1/admin
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.auth({user:'user0', pwd:'pwd0'})
1
> db.runCommand({connectionStatus: 1})
{
        "authInfo" : {
                "authenticatedUsers" : [
                        {
*                               "user" : "toto",
                                "db" : "admin"
                        },
                        {
*                               "user" : "user0",
                                "db" : "test_db"
                        }
                ],
                "authenticatedUserRoles" : [
                        {
                                "role" : "root",
                                "db" : "admin"
                        },
                        {
                                "role" : "read",
                                "db" : "test_db"
                        }
                ]
        },
        "ok" : 1
}
```

---

# MongoDB - List users

:arrow_right: Use `show users` to list users of a given database.

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
> show users
2018-05-22T23:44:56.226+0200 E QUERY    [thread1] Error: not authorized on test_db to execute command { usersInfo: 1.0 } :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
DB.prototype.getUsers@src/mongo/shell/db.js:1539:1
shellHelper.show@src/mongo/shell/utils.js:752:9
shellHelper@src/mongo/shell/utils.js:659:15
@(shellhelp2):1:1
```

:warning: Not authorized !

---

# MongoDB - List users

:arrow_right: Recreate user `user0` with `dbOwner` role.  
:arrow_right: Use command `db.dropUser('username')` to remove a user.

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://toto:toto123@127.0.0.1/admin
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.dropUser('user0')
true
> db.createUser({user:'user0', pwd:'pwd0', roles:["dbOwner"]})
Successfully added user: { "user" : "user0", "roles" : [ "dbOwner" ] }
> exit
bye
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
*> show users
{
        "_id" : "test_db.user0",
        "user" : "user0",
        "db" : "test_db",
        "roles" : [
                {
                        "role" : "dbOwner",
                        "db" : "test_db"
                }
        ]
}
```

---

# MongoDB - List databases / collections

:arrow_right: Use command `show databases` to list databases.  
:arrow_right: Use command `show collections` to list collections of the current database.  

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://toto:toto123@127.0.0.1/admin
MongoDB server version: 3.4.7
*> show databases
admin         0.000GB
local         0.000GB
test_db       0.000GB
```

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
*> show collections
MusicRecords
```

---

# MongoDB - View user's roles

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
*> show roles
{
        "role" : "dbAdmin",
        "db" : "test_db",
        "isBuiltin" : true,
        "roles" : [ ],
        "inheritedRoles" : [ ]
}
{
        "role" : "dbOwner",
        "db" : "test_db",
        "isBuiltin" : true,
        "roles" : [ ],
        "inheritedRoles" : [ ]
}
[...]
{
        "role" : "readWrite",
        "db" : "test_db",
        "isBuiltin" : true,
        "roles" : [ ],
        "inheritedRoles" : [ ]
}
{
        "role" : "userAdmin",
        "db" : "test_db",
        "isBuiltin" : true,
        "roles" : [ ],
        "inheritedRoles" : [ ]
}
```

---

# MongoDB - View user's roles (other way)

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
> db.auth({user:'user0',pwd:'pwd0'})
1
> db.getRoles()
[ ]
*> db.getRoles({showBuiltinRoles: true})
[
        {
                "role" : "__system",
                "db" : "admin",
                "isBuiltin" : true,
                "roles" : [ ],
                "inheritedRoles" : [ ]
        },
[...]
]
> use test_db
switched to db test_db
*> db.getRoles({showBuiltinRoles: true})
[
        {
                "role" : "dbAdmin",
                "db" : "test_db",
                "isBuiltin" : true,
                "roles" : [ ],
                "inheritedRoles" : [ ]
        },
[...]
]
```


---

# MongoDB - View user's privileges

:arrow_right: Use command `db.getRole('read', {showPrivileges: true})` to get privileges.

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
> db.getRole('read', {showPrivileges: true})
{
        "role" : "read",
        "db" : "test_db",
        "isBuiltin" : true,
        "roles" : [ ],
        "inheritedRoles" : [ ],
        "privileges" : [
[...]
                {
                        "resource" : {
                                "db" : "test_db",
                                "collection" : "system.indexes"
                        },
                        "actions" : [
                                "collStats",
                                "dbHash",
                                "dbStats",
                                "find",
                                "killCursors",
                                "listCollections",
                                "listIndexes",
                                "planCacheRead"
                        ]
                },
[...]
```

---

# MongoDB - Change user's password

:arrow_right: Use command `db.changeUserPassword` to change a password.

## .hcenter[\[Shell session\]]
```shell
*$ mongo mongodb://toto:toto123@127.0.0.1/admin
MongoDB shell version v3.4.7
connecting to: mongodb://user0:pwd0@127.0.0.1/test_db
MongoDB server version: 3.4.7
> use test_db
switched to db test_db
*> db.changeUserPassword("user0", "plop")
> db.auth({user:'user0', pwd:'pwd0'})
Error: Authentication failed.
0
> db.auth({user:'user0', pwd:'plop'})
1
```

---

# MonoDB - `GridFS`

:arrow_right: Use a mongoDB database as a file system.

## .hcenter[\[Shell session\]]
```shell
$ # put a file
$ mongofiles --verbose=-1 -u user0 -p pwd0 -d test_db put test_numpy.py
added file: test_numpy.py
$ # list files (and sizes)
$ mongofiles --verbose=-1 -u user0 -p pwd0 -d test_db list
test_numpy.py   976
$ # get a file
$ mongofiles --verbose=-1 -u user0 -p pwd0 -d test_db get test_numpy.py
finished writing to test_numpy.py
$ # delete a file
$ mongofiles --verbose=-1 -u user0 -p pwd0 -d test_db delete test_numpy.py
successfully deleted all instances of 'test_numpy.py' from GridFS
```

---

# MongoDB - Logs

:arrow_right: The path for the log file is specified in the `systemLog` section of the config file.

## .hcenter[\[/etc/mongodb.conf\]]
```json
storage:
  dbPath: "/home/mongodb"
  journal:
    enabled: false
systemLog:
  destination: file
* path: "/home/mongodb/mongodb.log"
  logAppend: true
net:
  bindIp: 127.0.0.1
  port: 27017
  maxIncomingConnections: 20000
security:
  authorization: enabled
```

---

# MongoDB - Logs

## .hcenter[\[/home/mongodb/mongodb.log\]]
.nowrap[
```accesslog
2018-05-21T00:02:48.089+0200 I CONTROL  [initandlisten] MongoDB starting : pid=3882 port=27017 dbpath=/home/mongodb 64-bit host=dell-e5450
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] db version v3.4.7
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] git version: cf38c1b8a0a8dca4a11737581beafef4fe120bcd
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.2g  1 Mar 2016
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] allocator: tcmalloc
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] modules: none
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] build environment:
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten]     distarch: x86_64
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten]     target_arch: x86_64
2018-05-21T00:02:48.090+0200 I CONTROL  [initandlisten] options: { config: "/etc/mongodb.conf", net: { bindIp: "127.0.0.1", unixDomainSocket: { pathPrefix: "/run/mongodb" } }, storage: { dbPath: "/home/mongodb", journal: { enabled: true } }, systemLog: { destination: "file", logAppend: true, path: "/home/mongodb/mongodb.log" } }
[...]
2018-05-23T00:15:20.591+0200 I NETWORK  [thread1] connection accepted from 127.0.0.1:35158 #21 (1 connection now open)
2018-05-23T00:15:20.591+0200 I NETWORK  [conn21] received client metadata from 127.0.0.1:35158 conn21: { application: { name: "MongoDB Shell" }, driver: { name: "MongoDB Internal Client", version: "3.4.7" }, os: { type: "Linux", name: "Ubuntu", architecture: "x86_64", version: "17.10" } }
2018-05-23T00:15:20.603+0200 I ACCESS   [conn21] Successfully authenticated as principal toto on admin
2018-05-23T00:15:20.604+0200 I ACCESS   [conn21] Unauthorized: not authorized on admin to execute command { getLog: "startupWarnings" }
2018-05-23T00:15:20.606+0200 I ACCESS   [conn21] Unauthorized: not authorized on admin to execute command { replSetGetStatus: 1.0, forShell: 1.0 }
2018-05-23T00:15:27.230+0200 I ACCESS   [conn21] Unauthorized: not authorized on test_db to execute command { listCollections: 1.0, filter: {} }
2018-05-23T00:16:14.463+0200 I ACCESS   [conn21] SCRAM-SHA-1 authentication failed for user0 on test_db from client 127.0.0.1:35158 ; AuthenticationFailed: SCRAM-SHA-1 authentication failed, storedKey mismatch
2018-05-23T00:16:26.888+0200 I ACCESS   [conn21] Successfully authenticated as principal user0 on test_db
2018-05-23T00:16:26.889+0200 I ACCESS   [conn21] Unauthorized: not authorized on admin to execute command { replSetGetStatus: 1.0, forShell: 1.0 }
2018-05-23T00:18:23.326+0200 I -        [conn21] end connection 127.0.0.1:35158 (1 connection now open)
```
]

---

# MongoDB - `GUI` ?

:arrow_right: Several MongoDB GUIs exist.
* [`robo3t`](https://github.com/Studio3T/robomongo) (former `Robomongo`): `GPLv3`, enhanced shell.
* [`studio3t`](https://studio3t.com/) (former `MongoChef`): **free for non-commercial use**, full GUI.
* [`adminMongo`](https://adminmongo.markmoffat.com/): `MIT` license, web-interface.
* many others (non-free, windows or macOS only, etc...)

---

# MongoDB - `adminMongo`

## .hcenter[\[Shell session\]]
```shell
$ git clone https://github.com/mrvautin/adminMongo.git && cd adminMongo
[...]
$ npm install
[...]
$ npm start

> admin-mongo@0.0.23 start /home/dubrayn/temp/adminMongo
> node app.js

adminMongo listening on host: http://0.0.0.0:1234
```

:arrow_right: `adminMongo` is [active](http://0.0.0.0:1234).

---

# MongoDB - `adminMongo`

.hcenter.shadow.w100[![](images/adminMongo0.png)]

---

# MongoDB - `adminMongo`

.hcenter.shadow.w100[![](images/adminMongo1.png)]

---

# MongoDB - `adminMongo`

.hcenter.shadow.w100[![](images/adminMongo2.png)]

---

# MongoDB - `adminMongo`

.hcenter.shadow.w100[![](images/adminMongo3.png)]

---

class: top

.vspace[]

.vspace[]

# MongoDB - Conclusions

.hcenter.w40[![](images/mongodb_logo.svg)]

:arrow_right: We have just seen a **tiny part** of what MongoDB is capable of.  
:bulb: Browse more doc/examples/tutorials at [https://www.mongodb.com](https://www.mongodb.com).

## Interactive use
There are two ways to **interactively** use a MongoDB database:
* connect with the mongo shell CLI tool, or
* use a GUI/webGUI.

## Non-interactive use
How to let a **`Python` program** use a MongoDB database ?  
:arrow_right: Connect to the server listening socket, write mongo shell commands and parse results

--
? :warning: **NO** :warning:  
:arrow_right: Use MongoDB `Python` bindings ? :v: **YES** :v:  
:bulb: Can even work with interactive use from `Python`...

---

# `PyMongo`

## In a nutshell
:arrow_right: Full-featured MongoDB `Python` bindings  
:+: The recommended way to use MongoDB from `Python`  
:+: Compatible with `CPython` `2.6`, `2.7`, `3.4+`, `PyPy`, and `PyPy3`

.vspace[]

.block[
* Repository: [https://github.com/mongodb/mongo-python-driver](https://github.com/mongodb/mongo-python-driver)
* Website: [http://api.mongodb.com/python/current/](http://api.mongodb.com/python/current/)
* License: `Apache` license
]

---

# `PyMongo` - Hello world

## .hcenter[\[mongodb/hello_world.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'admin0', 'pwd0', '127.0.0.1', 'admin'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  print(client.list_database_names()) # list databases

  db = client['test_db']
  print(db.list_collection_names()) # list collections

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/hello_world.py
['admin', 'config', 'local', 'test_db']
['MusicRecords']
```

---

# `PyMongo` - Insert document

## .hcenter[\[mongodb/insert_document.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']

  for i in range(3):
    data = { "run": 0, "time": 0.01 * i, "norm": 1.0}
    data_id = pycollection.insert_one(data).inserted_id

    print("id: %s" % (str(data_id)))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/insert_document.py
id: 6063439e1c836443066c6ff4
id: 6063439e1c836443066c6ff5
id: 6063439e1c836443066c6ff6
```

---

# `PyMongo` - Retrieve documents

## .hcenter[\[mongodb/retrieve_documents.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db.pycollection

  print("### find_one()")
  print(pycollection.find_one())
  print("### find()")
  for document in pycollection.find(): print(document)
  print("### find({'time': 0.01})")
  for document in pycollection.find({'time': 0.01}): print(document)

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/retrieve_documents.py
### find_one()
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
### find()
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
### find({'time': 0.01})
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
```

---

# `PyMongo` - Search document by `_id`

:arrow_right: Construct an `ObjectId` instance from the `_id` string value.

## .hcenter[\[mongodb/retrieve_by_id.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
from bson.objectid import ObjectId

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']
  myId = ObjectId('6063439e1c836443066c6ff5')
  print(pycollection.find_one({'_id': myId}))

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/retrieve_by_id.py
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
```

---

# `PyMongo` - Insert multiple documents

## .hcenter[\[mongodb/insert_documents.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']
  data = [{"pipo": i} for i in range(3)]
  pycollection.insert_many(data)
  for d in pycollection.find(): print(str(d))
  for i in range(3): pycollection.delete_one({"pipo": i})
  print("after...")
  for d in pycollection.find(): print(str(d))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/insert_documents.py
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
{'_id': ObjectId('606345904c49d6d63af42fa3'), 'pipo': 0}
{'_id': ObjectId('606345904c49d6d63af42fa4'), 'pipo': 1}
{'_id': ObjectId('606345904c49d6d63af42fa5'), 'pipo': 2}
after...
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
```

---

# `PyMongo` - Replace a document

## .hcenter[\[mongodb/replace_document.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
from bson.objectid import ObjectId

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']
  pycollection.replace_one({'time': 0.01}, {'toto': 'tutu'})
  for d in pycollection.find(): print(str(d))
  pycollection.replace_one({'toto': 'tutu'}, {'run': 0, 'time': 0.01, 'norm': 1.0})
  print('after...')
  for d in pycollection.find(): print(str(d))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/replace_document.py
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'toto': 'tutu'}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
after...
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
```

---

# `PyMongo` - Update a document

## .hcenter[\[mongodb/update_document.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
from bson.objectid import ObjectId

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']
  pycollection.update_one({'time': 0.01}, {'$inc': {'run': 3}})
  for d in pycollection.find(): print(str(d))
  pycollection.update_one({'time': 0.01}, {'$inc': {'run': -3}})
  print('after...')
  for d in pycollection.find(): print(str(d))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/update_document.py
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 3, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
after...
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff6'), 'run': 0, 'time': 0.02, 'norm': 1.0}
```

---

# `PyMongo` - Count

:arrow_right: Get the number of documents matching a criterion.
## .hcenter[\[mongodb/count.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
from bson.objectid import ObjectId

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db['pycollection']
  print(pycollection.count_documents({'time': 0.01}))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/count.py
1
```

---

# `PyMongo` - Range queries

:arrow_right: Use [query selectors](https://docs.mongodb.com/manual/reference/operator/query/)
to use **advanced queries**.  
:bulb: Use `sort()` to sort results.  

## .hcenter[\[mongodb/range_queries.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db.pycollection

  for document in pycollection.find({"time": {"$lt": 0.015}}).sort('time'):
    print(document)

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/range_queries.py
{'_id': ObjectId('6063439e1c836443066c6ff4'), 'run': 0, 'time': 0.0, 'norm': 1.0}
{'_id': ObjectId('6063439e1c836443066c6ff5'), 'run': 0, 'time': 0.01, 'norm': 1.0}
```

---

# `PyMongo` - Indexing

:arrow_right: Use `create_index()` to identify a key as an index for a collection.


## .hcenter[\[mongodb/create_index.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db.pycollection

  pycollection.create_index('time', unique = True)

  pycollection.insert_one({'time': 0.01})

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/create_index.py
ERROR: E11000 duplicate key error collection: test_db.pycollection index: time_1 dup key: { time: 0.01 }, full error: {'index': 0, 'code': 11000, 'keyPattern': {'time': 1}, 'keyValue': {'time': 0.01}, 'errmsg': ' E11000 duplicate key error collection: test_db.pycollection index: time_1 dup key: { time: 0.01 }'}
```

---

# `PyMongo` - Indexing

:arrow_right: Use `drop_index()` to remove an existing index for a collection.  
:bulb: Use `list_indexes()` to get a list of indexes.  

## .hcenter[\[mongodb/remove_index.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client.test_db
  pycollection = db.pycollection

  pycollection.drop_index('time_1')

  for i in pycollection.list_indexes():
    print(i)

except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/remove_index.py
SON([('v', 2), ('key', SON([('_id', 1)])), ('name', '_id_')])
```

---

# `PyMongo` - Numpy arrays

## .hcenter[\[mongodb/numpy_to_mongodb.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
import numpy as np
import bson
import pickle

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  for i in range(3):
    mat = np.eye(3) * i
    bindat = bson.binary.Binary(pickle.dumps(mat, protocol = 2))
    data_id = client['test_db']['numpy_test'].insert_one({'mat': bindat}).inserted_id
    print("id: %s" % (str(data_id)))
    print(mat)
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/numpy_to_mongodb.py
id: 606347c23629cec2ce762e84
[[0. 0. 0.]
 [0. 0. 0.]
 [0. 0. 0.]]
id: 606347c23629cec2ce762e85
[[1. 0. 0.]
 [0. 1. 0.]
 [0. 0. 1.]]
id: 606347c23629cec2ce762e86
[[2. 0. 0.]
 [0. 2. 0.]
 [0. 0. 2.]]
```

---

# `PyMongo` - Numpy arrays

## .hcenter[\[mongodb/mongodb_to_numpy.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
import numpy as np
import bson
import pickle

username, password, host, dbname = 'user0', 'pwd0', '127.0.0.1', 'test_db'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  for data in client['test_db']['numpy_test'].find():
    bindat = data["mat"]
    data_id = data["_id"]
    mat = pickle.loads(bindat)
    print("id: %s" % (str(data_id)))
    print(mat)
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

## .hcenter[\[Shell session\]]
```shell
$ mongodb/mongodb_to_numpy.py
id: 606347c23629cec2ce762e84
[[0. 0. 0.]
 [0. 0. 0.]
 [0. 0. 0.]]
id: 606347c23629cec2ce762e85
[[1. 0. 0.]
 [0. 1. 0.]
 [0. 0. 1.]]
id: 606347c23629cec2ce762e86
[[2. 0. 0.]
 [0. 2. 0.]
 [0. 0. 2.]]
```

---

# `PyMongo` - `GridFS`

## .hcenter[\[mongodb/gridfs_example.py\]]
```Python
#!/usr/bin/env python3

from pymongo import MongoClient
import pymongo.errors
from bson.objectid import ObjectId
import hashlib
import gridfs

def hash_content(content):
  m = hashlib.md5()
  m.update(content)
  return m.hexdigest()

username, password, host, dbname = 'admin0', 'pwd0', '127.0.0.1', 'admin'
client = MongoClient('mongodb://%s:%s@%s/%s' % (username, password, host, dbname))

try:
  db = client['test_gridfs']
  gridfs = gridfs.GridFS(db)
  filename = 'toto'
  content = '12f18481bh192d0 08 d h2j011jp'.encode('utf-8')
  print(hash_content(content))
  # save content as a GridFS file
  gridfs.put(content, filename = filename)
  # load content from a GridFS file
  fp = gridfs.get_last_version(filename = filename)
  print(hash_content(fp.read()))
except pymongo.errors.OperationFailure as e:
  print("ERROR: %s" % (e))
```

---

# `PyMongo` - `GridFS`

## .hcenter[\[Shell session\]]
```shell
$ mongodb/gridfs_example.py
4d5e1510e879cf18a2b05e89529a847b
4d5e1510e879cf18a2b05e89529a847b
```
:arrow_right: Use the CLI program `mongofiles` to list, get, put, delete... gridFS files.

## .hcenter[\[Shell session\]]
```shell
$ # list files
$ mongofiles --verbose=-1 -h 127.0.0.1 -u admin0 -p pwd0 --authenticationDatabase=admin -d test_gridfs list
toto    29
$ # get file
$ mongofiles --verbose=-1 -h 127.0.0.1 -u admin0 -p pwd0 --authenticationDatabase=admin -d test_gridfs get toto
$ # compute MD5
$ md5sum toto
4d5e1510e879cf18a2b05e89529a847b  toto
$ # delete file
$ mongofiles --verbose=-1 -h 127.0.0.1 -u admin0 -p pwd0 --authenticationDatabase=admin -d test_gridfs delete toto
```