According to this thread Göring supplied the Republicans with weapons, at the same time his airmen were fighting in Spain. Plus this makes Göring seem like he does not in the least care about his ideology and that Germany's fight against bolshevism is just hypocrisy.
I did some research about all this and i ended up in some conclusions. I shall present here the information that i have found and i will be pleased to here your opinions too or any information you have to share.
.Göring (who controlled Rheinmetall-Borsig) supplied arms to the Republicans; shipped to Greece supposedly for their use, the arms were transferred by Bodosakis to ships supposedly sailing to Mexico. He was also supplying the Nationalists, who got the best and latest weapons while the Republicans got the oldest and least serviceable. This supply peaked in 1937–38. Nationalists identified 18 vessels to Republican ports from 3 January 1937 and 11 May 1938, and estimated that Goering received the equivalent of one pound sterling per rifle. An earlier shipment from Hamburg to Alicante on 1 October 1936 by the Welsh ship Bramhill had 19,000 rifles, 101 machine guns and more than 20 million cartridges for the CNT militia in Barcelona
Beevor (2006).pp. 366–368, 538 note 4.
So the source is British historian Anthony Beevor and his book "The Battle of Spain". Im going to post some of the "incriminating" passages from the book.
You can find it here in PDF: https://www.pdfdrive.com/the-battle-for ... 26635.html
Spanish governments had purchased weapons from Germany since well
before the arrival of the Nazis in power. The colonial army in Morocco had
demanded mustard gas to use against the Riffian tribes, who later became their
most effective auxiliaries. Yet during the civil war the Republic purchased arms
from Nazi Germany, General Franco’s most important ally. Recent research 3 has now shown that what was long suspected is true: Colonel-General Hermann Göring, Minister President of Prussia and commander-in-chief of the Luftwaffe, was selling weapons to the Republic while his own men were fighting for Franco.
On 1 October 1936 the Welsh cargo ship Bramhill reached Alicante, having come from Hamburg with a consignment of 19,000 rifles, 101 machine-guns and
more than 28 million cartridges, all ordered by the CNT in Barcelona for its
militia columns. The presence of the Bramhill in Alicante was observed by
officers on HMS Woolwich. Her captain immediately informed the Foreign
Office, which investigated the matter. The German government made excuses,
saying that Hamburg was a free port, yet it was clear that this cargo had arrived with official blessing. The Foreign Office left the matter there. In fact, the architect of this secret sale of arms to the Republic was Hermann Göring. He used as intermediaries the well-known arms trafficker Josef Veltjens, who had already sold arms to General Mola before the rising, but above all Prodromos Bodosakis-Athanasiades, a piratical Greek on close terms with the country’s
Bodosakis-Athanasiades was the chief shareholder and chief executive of Poudreries et Cartoucheries Helléniques SA, whose main associate and backer was Rheinmetall-Borsig which, in turn, was controlled by Göring
Bodosakis passed the demands for weapons which he received to Rheinmetall-Borsig and the Metaxas government provided enduser certificates stating that the equipment was destined for the Greek army. When the shipment reached Greece, Bodosakis transferred it to another vessel supposedly sailing to Mexico, but in fact to Spain. As Bodosakis was dealing with the nationalists as well as the Republic, he had to split shipments between vessels, with the best and latest weapons destined for the nationalists and the oldest and least serviceable for the republicans.
In 1937 and 1938, when the sale of German weapons to the Republic was
reaching its peak, Bodosakis’s company was ordering shipments from
Rheinmetall-Borsig worth anything up to 40 million Reichmarks (£3.2 million at
the time). These consignments were almost all for the Republic and one can befairly sure that Bodosakis was charging five or six times what he had paid Göring. It is more than likely that he then had to pay a significant share of his
immense profits to Göring personally, rather than to Rheinmetall-Borsig, and this was on top of payments to the Metaxas regime and other officials.
There was even a Soviet angle to this very free market trade between Nazi
Germany and republican Spain. In November 1937 Bodosakis travelled to
Barcelona in a Soviet aircraft, accompanied by George Rosenberg, son of the purged Soviet ambassador. Rosenberg, who was a shipping agent and wheeler�dealer, and Bodosakis came to sign a contract with the Republic for £2.1 million to supply ammunition. On this occasion, as on all others, they insisted on full
payment in hard currency in advance. The supply of German weaponry to the
Republic continued until the very end of the war, as the international
commission for the repatriation of foreign volunteers established in January 1939.
So we have a Greek businessman named Bodosakis and Göring supposedly having an agreement with the latter. The agreement is about the transfer of weapons to the republican forces through the Greek Ammunition Industry (later named PYRKAL). The company allegedly is an intermediary between Göring and the Republican government, and the author claims that PYRKAL was a branch of Rheimmental-Borsig. This apparently is not true because owner (shareholder) and chief of the Company was Bodosakis himself.
The Wikipedia thread for PYRKAL:
In 1936-37 during the Spanish Civil War German arms were supplied to the Spanish Republicans from Rheinmetall-Borsig, then controlled by Hermann Göring, even though German forces were fighting with the Spanish Nationalists. Arms shipped to Greece with a Greek end-user certificate were split by Bodosakis, with arms for the Republicans transferred to ships supposedly sailing to Mexico
I haven't found any Greek source saying that Bodosakis made any agreement with Göring but that Bodosakis ordered German equipment with the permission of the Greek dictator. The weapons that were ordered supposedly would cover Greek army needs. With this in mind, we conclude that Göring did not had any agreement but Bodosakis made fools out of the German companies and sold the weapons to Spain.(We must note that Greek-German economic relations were strong during the years 1936-1939. Greece exported tobacco to Germany and Greece imported arms and other products from the Germans. For example the greek destroyer RHNS Vasilissa Olga, had a British hull, but its gun batteries were german 127mm Rheimmental-Borsig SK C/34, and it's anti-air were 4 german SK C/30.). It should be noted that PYRKAL had licensed equipment and produced 6.5x34mm Mannlicher cartridges and Schneider cannon shells.
Even though Greece had a conversative dictatorship (it was pro-British and more like of a British puppet which officially declared that it was neutral), the government gave permission to Bodosakis to send arms to the communists and i have also found out that Greek ships transported Soviet equipment loaded in Odessa to Spain.
 ( DGFP Vol.III, No. 118 ).
Moreover, Bodosakis received his first order from Republican Spain (they requested 5.000.000 cartridges) in mid-September of 1936. Later on, another order arrived which requested 20.000.000 cartridges. In order to complete these orders, the company increased it's work force and managedto reach a production of 400.000 cartridges per day. In 1937 the Republican orders started increasing, Bodosakis bought German machinery and made further increases in personnel. Production was increased to 2.000.0000 cartridges daily. In order to keep up with the Republican requests he made deals with German, Swedish and Austrian arms companies, bought empty cartridges and shells, brought the shipments in Athens (where his industry was), filled them with gunpowder and sent them off to Spain. 
He even proposed the government to send equipment to the Republicans, which would came from the Greek army stockpiles. 
 Sotiropoulos, "Bodosakis", Athens 1985, p. 153
 Ibid p.153-154
According to Greek Foreign Ministry documents, the ships which would transport the military supplies sailed off from Piraeus (port in Athens) while both sides have agreed that the iconic destination would be Mexico (a county that helped the republican cause greatly). After the equipment was loaded in ships stationed in Piraeus, they sailed in certain Aegean Islands where the ships were "camouflaged" and even changed names, so they wouldn't raise the suspicions of the Italians when passing Messina's Straits. When the Germans, Italians and the Spanish nationalists learned of these actions, they protested heavily, but Metaxas (the Greek dictator) answered that the upper claims were untrue and that the destination of the ships was Mexico.  
 Foreign Ministry Archives, Athens: AYE/1937/A/1/1/5: note of D. Kapsalis (23 July 1937)
(Original: Αρχεία Υπουργείου Εξωτερικών (ΑΥΕ), Αθήνα: ΑΥΕ/1937/A/1/1/5: σημείωμα Δ. Καψάλη (23 Ιουλίου 1937) )
 Sotiropoulos, "Bodosakis", Athens, 1985, p.156-157
The documents that were exchanged between the Greek and Spanish governments confirm that the Greeks supplied the Republicans. In the 9th of September 1937 the Immigration Office notified the Greek Foreign Ministry that a certain Sephardic Jew with Spanish citizen, Alberto Levy, who lived in Greece, was arrested while on a ship which was transporting military supplies. The ship was arrested by Spanish nationalists and the Jew had been accused of weapon smuggling and thus he was sentenced to death. According to the Immigration Office, Levy was indeed an intermediary for weapon smuggling, between the Greek and Spanish republican government. 
 Foreign Ministry Archives, Immigration Office to Foreign Office, 9 September 1937, 75/11/4/19
(Original: ΑΥΕ/1937/A/I/33/3: Υπηρεσία Αλλοδαπών προς υπουργείο Εξωτερικών, 9 Σεπτεμβρίου 1937, αρ. 75/11/4/19)
All in all, i have concluded that the Germans did not had a plan all along to supply the Reds in Spain, that it was the deeds of a certain Greek businessman (one of the most influential if his time) and that Germany supplied Greece with weaponry for it's army and not because Göring had everything agreed with the Greek industrialist.
I would like to hear your opinions too.
If you have any info about the weapon smuggle in the Spanish civil war and especially about Göring's role, i would like you to share it.